AN543 S i475 X P ROGRAMMING G UIDE 1. Introduction This document provides an overview of the programming requirements for the Si475x-A10/A20/A30/A40/A55 and Si475xC-A55 AM/FM receiver. The hardware control interface and software commands are detailed along with several examples of the required steps to configure the device for various modes of operation. Table 1 provides a programming guide cross-reference for each Si475x part released by Silicon Labs to date. This programming guide focuses on the Si475x/5xC-A55 release; however, features, properties, ranges, and defaults that differ from the Si475x-A10 to Si475x-A40 are noted as well. Refer to previous versions of this document for earlier firmware revisions. Table 1. Si475x Firmware Revisions Part # Part Revision FMRX Component AMRX Component Si475x-A10 1.0 3.2.3 3.2.3 Si475x-A20 2.0 8.0.8 7.0.5 Si475x-A30 3.0 10.0.8 9.0.6 Si475x-A40 4.0 13.0.11 12.0.10 Si475x-A55 5.5 15.0.2 14.0.1 Si475xC-A55 5.5 15.0.2 14.0.1 2. Overview This devices in this product family are programmed using commands and responses. To perform an action, the system controller writes a command byte and associated arguments, which cause the device to execute the given command. The device will, in turn, provide a response depending on the type of command that was sent. The device has a slave control interface that allows the system controller to send commands to and receive responses from the device using 2-wire mode (I2C compatible). 3. Terminology CTS--Clear to send STC--Seek/Tune Complete NVM--Non-volatile internal device memory Device--Refers to the AM/FM Receiver System Controller--Refers to the system microcontroller CMD--Command byte ARGn--Argument byte (n = 1 to 7) STATUS--Status byte RESPn--Response byte (n = 1 to 15) Rev. 0.9 10/16 Copyright (c) 2016 by Silicon Laboratories Silicon Laboratories Confidential. Information contained herein is covered under non-disclosure agreement (NDA). AN543 AN543 4. Control Interface The Si475x provides an I2C-compatible, 2-wire control interface. In powerdown mode, all circuitry is disabled except for the device control interface. The device comes out of powerdown mode when the POWER_UP command is written to the command register. Once in powerup mode, the device accepts additional commands such as tuning. The device will not accept commands while in powerdown mode, with the exception of the powerup command. If the system controller writes a command other than POWER_UP when in powerdown mode, the device does not respond, and the command is ignored. Setting the RSTB pin low places the device in reset mode. In reset mode, all circuitry is disabled including the device control interface; registers are set to their default settings, and the control bus is disabled. 4.1. 2-Wire Control Interface Figure 1 and Figure 2 show the 2-wire control interface read and write timing parameters and diagrams, respectively. Refer to the Si475x data sheet for timing parameter values. SCL SDA tSU:STA tHD:STA tLOW START tr:IN tHIGH tr:IN tf:IN tSP tSU:STO tBUF 70% 30% 70% 30% tHD:DAT tSU:DAT tf:IN, tf:OUT tPD:DAT STOP START Figure 1. I2C Control Interface Read and Write Timing Parameters SCL SDA (Write) Command 7-0 A6-A0, 0 START SDA (Read) ADDRESS + R/W ACK ADDRESS + R/W ACK Status 7-0 A6-A0, 1 START DATA Arg1 7-0 ACK DATA DATA Rev. 0.9 STOP ACK STOP Response 7-0 ACK DATA Figure 2. I2C Control Interface Read and Write Timing Diagram 2 ACK AN543 Two-wire bus mode uses the SCL and SDA pins for signaling. A transaction begins with the START condition, which occurs when SDA falls while SCL is high. Next, the system controller drives an 8-bit control word serially on SDA, which is captured by the device on rising edges of SCL. The control word consists of a seven-bit device address followed by a read/write bit (read = 1, write = 0). The device acknowledges the control word by driving SDA low on the next falling edge of SCL. For write operations, the system controller next sends a data byte on SDA, which is captured by the device on rising edges of SCL. The device acknowledges each data byte by driving SDA low for one cycle on the next falling edge of SCL. For each write transaction, the first byte is a command and the following bytes are arguments. For read operations, after the device has acknowledged the control byte, it will drive an eight-bit data byte on SDA, changing the state of SDA on the falling edges of SCL. The system controller acknowledges each data byte by driving SDA low for one cycle on the next falling edge of SCL. If a data byte is not acknowledged by the system controller, the transaction will end. For each read transaction, the first byte is the status byte and the following bytes are the response data from the receiver. A 2-wire transaction ends with the STOP condition, which occurs when SDA rises while SCL is high. 5. Powerup and Powerdown There are two procedures for powering up a receiver to move it from powerdown mode to the powerup mode. The first is a powerup from internal receiver memory. The second is a powerup from a firmware component patch that is stored in system controller memory. Patches can be applied to a firmware component by the system controller via a download mechanism to address field issues, errata, or adjust device behavior. Patches are encrypted and unique to a particular device firmware version, cannot be generated by customers, and can be used to replace a portion of the component (to address errata, for example) or to download an entirely new component. The user must verify that the device contains the correct base firmware to support the patch as described later in this section. It has been noted that some crystals require greater startup current and settling times than others. The procedure below is meant to apply to a wide variety of such crystals, providing maximum current and 40 ms for crystal oscillation to stabilize. If there are still difficulties with POWER-UP that may be related to your choice of crystal, please refer to the settings and hardware options in "AN750: Si475x 4 MHz Crystal Compatibility Power-Up Procedure". Rev. 0.9 3 AN543 5.1. Powerup Receiver from Internal Memory START Supply VA, VD, and VIO while keeping the RSTB = 0 After a minimum of 100 s, set RSTB = 1 After a minimum of 100 s, continue to the next step Send the POWER_UP command for desired function (AM, FM) Wait at least 100 ms Send command to force CTS = 1 Send second POWER_UP command for the desired function (AM, FM) Commence normal operation Send POWER_DOWN command 1. Supply VA, VD, and VIO while keeping the RSTB = 0. Power supplies may be sequenced in any order. 2. After a minimum of 100 s, set RSTB = 1. 3. After a minimum of 100 s, continue to the next step. 4. Send the POWER_UP command for the desired function (AM, FM). 4 Rev. 0.9 AN543 Example (with crystal 4 MHz, FM function): 1. Provide the initial POWER_UP Command: Action Data Description CMD 0x01 POWER_UP ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE Note: Change this value to the capacitance that matches the crystal in use. ARG3 0x27 SETS CRYSTAL BIAS = 7 w/ FASTBOOT ARG4 0x00 0x10 0x20 BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal ARG5 0x00 DIGITAL CORE DISABLED/CRYSTAL OSCILLATOR DISABLED STATUS NO CTS bit returned 2. Apply a wait time of at least 100 ms. 3. Apply the following command: Action Data Description CMD 0xFB CONTROL REGISTER WRITE COMMAND ARG1 0X06 CONTROL REGISTER ADDRESS ARG2 0x80 FORCES CTS = 1 STATUS NO CTS bit returned 4. Apply the following command: Action Data Description CMD 0x01 POWER_UP ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE Note: Change this value to the capacitance that matches the crystal in use. ARG3 0x23 SETS CRYSTAL BIAS = 3 w/ FASTBOOT ARG4 0x00 0x10 0x20 BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal ARG5 0x11 DIGITAL CORE ENABLED/CRYSTAL OSCILLATOR ENABLED STATUS CTS = 1 Note: For more details on the external circuit for the 4 MHz crystal, see "AN750: Si475x 4 MHz Crystal Circuit and Power-Up Procedure". 5. The device is ready to commence normal operation and accept additional commands. Refer to Figure 3. Rev. 0.9 5 AN543 VIO VD VA 100 s min RSTB 100 s min SCL SDA POWER_UP Command > 10 s Figure 3. Powerup Timing 6. If desired, send the POWER_DOWN command. Example: POWER_DOWN Command Action Data Description CMD 0x11 POWER_DOWN ARG1 0x00 Disable oscillator (ARG1 may be omitted with the same result) STATUS 0x80 CTS = 1 7. It is now possible to move to the powerup state by returning to step 4. 6 Rev. 0.9 AN543 5.2. Powerup Receiver from a Patch START A C Supply VA, VD , and VIO while keeping the RSTB = 0 Send the PO W ER _UP com m and for the desired function (AM , FM ) Send the POW ER _UP com m and w ith boot loader function After a m inim um of 100 s, set RSTB = 1 W ait at least 100 m s W ait at least 100 m s After a m inim um of 100 s, continue to the next step Send com m and to force CTS = 1 Send com m and to force CTS = 1 Send second PO W ER_UP com m and for the desired function (AM , FM ) Send second POW ER_UP com m and with bootloader function Send PART_INFO com m and Send patch data. Send PO W ER_DO W N com m and Send the POW ER _UP com m and for the desired function (AM , FM ) Verify Firm ware and ROM revision? A B C B Com m ence norm al operation. Send POW ER_DOW N com m and. B 1. Supply VA, VD, and VI0 while keeping the RSTB = 0. Power supplies may be sequenced in any order. 2. After a minimum of 100 s, set RSTB = 1. 3. After a minimum of 100 s, proceed to the next step. 4. (Optional - step 1 of 3 to verify part firmware revision and ROM revision.) Both part firmware revision and ROM revision must be compatible with a partial patch and ROM revision must be compatible with a full patch. Send the POWER_UP command for the desired function (AM, FM). Rev. 0.9 7 AN543 Example (with crystal 4 MHz, FM function): 1. Provide the initial POWER_UP Command: Action Data Description CMD 0x01 POWER_UP ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE Note: Change this value to the capacitance that matches the crystal in use. ARG3 0x27 SETS CRYSTAL BIAS = 7 w/ FASTBOOT ARG4 0x00 0x10 0x20 BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal ARG5 0x00 DIGITAL CORE DISABLED/CRYSTAL OSCILLATOR DISABLED STATUS NO CTS bit returned 2. Apply a wait time of at least 100 ms. 3. Apply the following command: Action Data Description CMD 0xFB CONTROL REGISTER WRITE COMMAND ARG1 0X06 CONTROL REGISTER ADDRESS ARG2 0x80 FORCES CTS = 1 STATUS NO CTS bit returned 4. Apply the following command: Action Data Description CMD 0x01 POWER_UP ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE Note: Change this value to the capacitance that matches the crystal in use. ARG3 0x23 SETS CRYSTAL BIAS = 3 w/ FASTBOOT ARG4 0x00 0x10 0x20 BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal ARG5 0x11 DIGITAL CORE ENABLED/CRYSTAL OSCILLATOR ENABLED STATUS CTS = 1 Note: For more details on the external circuit for the 4 MHz crystal, see "AN750: Si475x 4 MHz Crystal Circuit and Power-Up Procedure". 5. (Optional - step 2 of 3 to verify part firmware revision and ROM revision). Verify part firmware revision and ROM revision. Send the PART_INFO command. 8 Rev. 0.9 AN543 Example: PART_INFO Command Action Data Description CMD 0x02 PART_INFO STATUS 0x80 CTS = 1 RESP1 0x06 Chip revision, 6 RESP2 0x35 Part number (last two digits) 0x35 = 53, or Si4753 RESP3 0x32 Firmware major revision = ASCII character "2" RESP4 0x30 Firmware minor revision = ASCII character "0" RESP5 0x00 Firmware build version = 0 RESP6 0x00 Reserved, values will vary RESP7 0x00 Reserved, values will vary RESP8 0x04 ROM ID In this example, the part revision is 2.0.0 and the ROM ID is 4. Ensure that partial patches received from Silicon Labs are intended for use with the part firmware revision and ROM, and that full patches are intended for use with the ROM ID as shown in Table 2. It is possible to verify the FM and AM component firmware revisions with the FUNC_INFO command, however, this is not necessary because there is always a unique mapping of component revision to part revision. Table 2. Si475x Firmware and ROM Compatibility Part # Part Revision ROM ID FM Revision AM Revision Si475x-A10 1.0 2 3.2.3 3.2.3 Si475x-A20 2.0 4 8.0.8 7.0.5 Si475x-A30 3.0 5 10.0.8 9.0.6 6. (Optional--step 3 of 3 to verify part firmware revision and ROM revision.) Send the POWER_DOWN command. This step is required before proceeding with the patching procedure if steps 4 and 5 have been followed. Example POWER_DOWN Command Action Data Description CMD 0x11 POWER_DOWN ARG1 0x00 Disable oscillator (ARG1 may be omitted with the same result) STATUS 0x80 CTS = 1 7. Send the POWER_UP command for boot loader function. Rev. 0.9 9 AN543 Example (with crystal 4 MHz, boot loader function): 1. Provide the initial POWER_UP Command: Action Data Description CMD 0x01 POWER_UP ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE Note: Change this value to the capacitance that matches the crystal in use. ARG3 0x27 SETS CRYSTAL BIAS = 7 w/ FASTBOOT ARG4 0x00 0x10 0x20 BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal ARG5 0x00 DIGITAL CORE DISABLED/CRYSTAL OSCILLATOR DISABLED STATUS NO CTS bit returned 2. Apply a wait time of at least 100 ms. 3. Apply the following command: Action Data Description CMD 0xFB CONTROL REGISTER WRITE COMMAND ARG1 0X06 CONTROL REGISTER ADDRESS ARG2 0x80 FORCES CTS = 1 STATUS NO CTS bit returned 4. Apply the following command: Action Data Description CMD 0x01 POWER_UP ARG1 0X77 NORMAL OPERATION, 4 MHz Crystal ARG2 0x1F SETS CRYSTAL LOAD CAPACITANCE Note: Change this value to the capacitance that matches the crystal in use. ARG3 0x23 SETS CRYSTAL BIAS = 3 w/ FASTBOOT ARG4 0x00 0x10 0x20 BOOT LOADER FM Receive, 4 MHz Crystal AM Receive, 4 MHz Crystal ARG5 0x11 DIGITAL CORE ENABLED/CRYSTAL OSCILLATOR ENABLED STATUS CTS = 1 5. Send the patch data. The patch file provided by Silicon Labs typically has a .sg extension. The system controller must send each line of 8 bytes, wait for a CTS, then send the next line of 8 bytes, etc., until the entire patch has been sent. An example showing the first few lines and final line of a patch file is shown below. Note that the "#" character indicates a comment and the patch file indicates the required ROM ID for a partial or full download. If the checksum fails, the part issues an error code, ERR (bit 6 of the STATUS byte received after each 8-byte transfer), and halts. The part must be reset to recover from this error condition. 10 Rev. 0.9 AN543 The following is an example of a patch file: # COPYRIGHT=2011 Silicon Laboratories, Inc. # GENERATED=13:53 May 23 2011 # ROMID=0x04 # PATCHID=0x228C # REQUIRES=NONE # SIZE=8272 # FUNCTION=FMRX # MAJOR=8 # MINOR=0 # BUILD=8 # CRCT=0x81CF # CRCM=0x0A6C # CRCP=0xEC8D # CRCX=0x66EE # CRCY=0x6381 # CRCZ=0xA805 0x04,0x11,0x81,0xCF,0x00,0x00,0x0D,0xC6 0x05,0xAE,0xE1,0xBD,0xB4,0x90,0x07,0x33 0x06,0xD9,0x3D,0x11,0xF7,0x25,0xCB,0x06 0x17,0x7A,0xF8,0xD0,0x71,0x10,0x3F,0xB7 0x1F,0xBF,0xFF,0x7E,0x42,0xE7,0x53,0x05 ... [Additional Lines] ... 0x08,0x21,0xAB,0xB5,0xF1,0x7A,0xD6,0x5A 0x08,0x10,0x0E,0x9E,0x3B,0xD1,0x01,0xF4 0x08,0xBF,0x8D,0x94,0xB0,0x2D,0xCF,0xFF 0x05,0x8D,0xB1,0x22,0xF2,0x8D,0x22,0x8C # END Rev. 0.9 11 AN543 Example: First line of the patch file example Action Data CMD 0x04 ARG1 0x11 ARG2 0x81 ARG3 0xCF ARG4 0x00 ARG5 0x00 ARG6 0x0D ARG7 0xC6 STATUS 0x80 Description CTS = 1 Second line of the patch file example CMD 0x05 ARG1 0xAE ARG2 0xE1 ARG3 0xBD ARG4 0xB4 ARG5 0x90 ARG6 0x07 ARG7 0x33 STATUS 0x80 CTS = 1 6. Send the POWER_UP command for the desired function (AM, FM). Example (with crystal 4 MHz, FM function): POWER_UP Command Action Data Description CMD 0x01 POWER_UP ARG1 0x77 Normal operation ARG2 0x27 Crystal load capacitance = 15.803 pF each pin ARG3 0x23 Disables CTS interrupt, crystal bias = 3, enable fastboot ARG4 0x10 FM function, crystal frequency 4 MHz ARG5 0x11 Crystal STATUS 0x80 CTS = 1 Example (with external clock 4 MHz, FM function): 12 Rev. 0.9 AN543 POWER_UP Command Action Data Description CMD 0x01 POWER_UP ARG1 0x77 Normal operation ARG2 0x00 Crystal load capacitance = 5 pF each pin ARG3 0x23 Disables CTS interrupt, crystal bias = 3, enable fastboot ARG4 0x10 FM function, clock frequency 4 MHz ARG5 0x12 External clock STATUS 0x80 CTS = 1 7. The device is ready to commence normal operation and accept additional commands. 8. If desired, send the POWER_DOWN command. Example: POWER_DOWN Command Action Data Description CMD 0x11 POWER_DOWN ARG1 0x00 Disable oscillator (ARG1 may be omitted with the same result) STATUS 0x80 CTS = 1 9. It is now possible to move to the powerup state by returning to step 7. Rev. 0.9 13 AN543 6. Timing 6.1. Command and Property Timing When the user reads a response over the I2C bus, the first 8 bits returned are the STATUS register. Bit 7 of the STATUS register is the CTS bit (Clear to Send). When CTS is 1, it indicates that the chip is ready to receive a new command. Seek and Tune commands may take longer to complete than most other commands, so they also use the STC bit (Seek/Tune Complete) to indicate they have completed. STC is bit 0 of the STATUS register. When the user sends any command, the CTS bit will immediately reset to 0. CTS will remain 0 while the chip processes the command. When the chip is finished processing the command, the CTS bit will be set back to 1. Before sending another command, the user may poll CTS by reading the first byte of response until CTS = 1. If the user has enabled the optional CTS interrupt, then the INTB pin will pulse low immediately after CTS has been set to 1, to notify the user that the previous command has completed. For information on how to enable the CTS interrupt, see the INT_CTL_ENABLE property and CTSIEN bit in the arguments for the POWER_UP command. The commands for seek and tune (FM_TUNE_FREQ, FM_SEEK_START, etc.) will cause CTS to reset to 0 for a short time, but they will set CTS back to 1 after the seek or tune has started. The seek or tune is progressing even though CTS has been set back to 1. Although the user is free to send another command at this time, it is highly recommended to wait until the STC (Seek/Tune Complete) bit has been set to 1 before sending another command. The only exception is the AM/FM_RSQ_STATUS command, which may be sent at any time because it can be used to cancel the seek/tune in progress and check the status of which station seek is currently on. When the seek/tune completes, the STC bit will be set to 1. The user may poll STC by reading the first byte of response until STC = 1. If the user has enabled the optional STC interrupt, then the INTB pin will pulse low immediately after STC has been set to 1, to notify the user that the seek or tune has completed. For information on how to enable the STC interrupt, see the INT_CTL_ENABLE property. After the seek or tune has completed, the user may acknowledge the completion by sending the AM/ FM_RSQ_STATUS command with the STCACK bit set to 1. This will reset the STC bit back to 0. After this, the user may send another seek or tune command. Alternatively a new seek or tune command will also clear the STC bit when it begins. Figure 4 shows a seek or tune command with the optional CTS and STC interrupts enabled. The timing parameters are shown in Table 3. Control Bus Command Command FM_TUNE_FREQ FM_RSQ_STATUS CTS Bit STC Bit INTB tINT tCTS tSTC Figure 4. CTS and STC Timing Model 14 Rev. 0.9 AN543 Table 3. Command Timing Parameters for Common Commands Command tCTS tSTC tINT POWER_UP 100 ms -- 3 s POWER_DOWN <1000 s -- 3 s FUNC_INFO <200 s -- 3 s SET_PROPERTY <200 s -- 3 s GET_PROPERTY <200 s -- 3 s GET_INT_STATUS <200 s -- 3 s AGC_STATUS <200 s -- 3 s ANA_AUDIO_PIN_CFG <200 s -- 3 s Table 4. Command Timing Parameters for FM Receiver Command tCTS tSTC tINT FM_TUNE_FREQ <200 s 21 ms 3 s FM_TUNE_FREQ (fast tune) <200 s 5 ms 3 s FM_SEEK_START <200 s See Note below. 3 s FM_RSQ_STATUS <200 s -- 3 s FM_ACF_STATUS <200 s -- 3 s FM_RDS_STATUS <200 s -- 3 s FM_RDS_BLOCKCOUNT <200 s -- 3 s *Note: tSTC is seek time per channel. Total seek time depends on bandwidth, channel spacing, and number of channels to next valid channel. Worst case seek time complete for FM_SEEK_START is: FM_SEEK_BAND_TOP - FM_SEEK_BAND_BOTTOM ------------------------------------------------------------------------------------------------------------------------------------------------- + 1 t STC FM_SEEK_FREQ_SPACING For Si475x-A30, the seek time will require an additional tSTC + tSTC(FAST) for channel spacings other than 200 kHz. Table 5. Command Timing Parameters for AM Receiver Command tCTS tSTC tINT AM_TUNE_FREQ 100 s 40 ms 3 s AM_SEEK_START 100 s See Note below. 3 s AM_RSQ_STATUS 100 s -- 3 s AM_ACF_STATUS 100 s -- 3 s *Note: tSTC is seek time per channel. Total seek time depends on bandwidth, channel spacing, and number of channels to next valid channel. Rev. 0.9 15 AN543 6.2. Alternate Frequency (AF) Timing The Si4754/55/56/57 features a flexible FM tune command that allows for a number of operational choices. While tuned to the current station, the receiver can quickly tune to candidate FM stations and perform one of three operations. 1. Tune to the FM station and stay tuned. 2. Tune to the FM station; check the selected signal metrics, and jump back to the original station (AF check). 3. Tune to the FM station; check the selected signal metrics, and decide if the receiver is kept tuned to the FM station (AF Jump) or re-tuned to the original station. The timing diagrams for AF tune and AF check are shown in Figure 5 and Figure 6, respectively. F1 F2 F2 F2 } F1 Audio Audio T1 T2 AF Tune command issued T3 AF station metrics qualified: Above thresholds Tuner stays on AF station AF Tune Initiated T1 ~ 0.5 ms T2 ~ 1 ms T3 ~ 4.8 ms Figure 5. AF Tune Diagram 16 T1 Rev. 0.9 AN543 F2 F2 F2 F1 } F1 } F1 Audio F1 Audio T1 T2 AF Check command issued T4 T2 T1 AF Station metrics measured and qualified. Tuner jumps back to F1 AF Check Initiated T1 ~ 0.5 ms T2 ~ 1 ms T4 ~ 7 ms Figure 6. AF Check Timing Diagram Rev. 0.9 17 AN543 6.3. Fast Tune Timing The timing diagram for fast tune is shown in Figure 7. F1 } F1 F2 F2 Audio Audio T1 T1 T2 Fast Tune command issued Fast Tune Initiated T1 ~ 0.5 ms T2 ~ 1 ms Figure 7. Fast Tune Timing Diagram 18 Rev. 0.9 AN543 7. Commands and Properties 7.1. Common Commands and Properties The following properties and commands are common to all receiver modes. Table 6. Common Receiver Command Summary Number Name Summary 0x01 POWER_UP Power-up device and mode selection. Modes include operational function (AM, FM) and audio interface configuration. 0x02 PART_INFO Returns the part information of the device. 0x11 POWER_DOWN 0x12 FUNC_INFO 0x13 SET_PROPERTY Sets the value of a property. 0x14 GET_PROPERTY Retrieve a property's value. 0x15 GET_INT_STATUS Read interrupt status bits. 0x17 AGC_STATUS 0x1B ANA_AUDIO_PIN_CFG 0x1C INTB_PIN_CFG Power-down the device. Returns the firmware revision and patch revision. Reports the status of the AGC. Configures the analog audio pins. Configures behavior of INTB and A1 pins. Table 7. Common Receiver Property Summary Number Name 0x0000 INT_CTL_ENABLE 0x0300 AUDIO_ANALOG_VOLUME 0x0301 AUDIO_MUTE Default A10 A20 0x0000 0x0000 0 0 0x003F 63 A30 Summary A40 A55 0x0000 0x0000 0x0000 Interrupt enable property. 0 0 0 0x003F 0x003F 0x003F 0x003F Sets the analog audio volume. 63 63 63 63 0x0000 0x0000 0 0 Rev. 0.9 0x0000 0x0000 0x0000 0 0 0 Audio mute property. 19 AN543 Table 8. Status Response for the FM Receiver 20 Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT Bit Name Function 7 CTS Clear to Send. 0 = Wait before sending next command. 1 = Clear to send next command. 6 ERR Error. 0 = No error. 1 = Error. 5:4 Reserved Values may vary. 3 RSQINT Received Signal Quality Interrupt. 0 = Received Signal Quality measurement has not been triggered. 1 = Received Signal Quality measurement has been triggered. 2 RDSINT Radio Data System Interrupt. 0 = Radio data system interrupt has not been triggered. 1 = Radio data system interrupt has been triggered. 1 ACFINT Automatically Controlled Features Interrupt. 0 = ACF measurement has not been triggered. 1 = ACF measurement has been triggered. 0 STCINT Seek/Tune Complete Interrupt. 0 = Tune complete has not been triggered. 1 = Tune complete has been triggered. Rev. 0.9 AN543 Table 9. Status Response for the AM Receiver Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT X ACFINT STCINT Bit Name 7 CTS Clear to Send. 0 = Wait before sending next command. 1 = Clear to send next command. 6 ERR Error 0 = No error. 1 = Error. 5:4 Reserved Values may vary. 3 RSQINT Received Signal Quality Interrupt 0 = Received Signal Quality measurement has not been triggered. 1 = Received Signal Quality measurement has been triggered. 2 Reserved Value may vary. 1 ACFINT Automatically Controlled Features Interrupt. 0 = ACF measurement has not been triggered. 1 = ACF measurement has been triggered. STCINT Seek/Tune Complete Interrupt. 0 = Tune complete has not been triggered. Do not send a new TUNE/SEEK command. 1 = Tune complete has been triggered. It is safe to send a new TUNE/ SEEK command. 0 Function Rev. 0.9 21 AN543 If the ERR bit in the STATUS response is set for a command or property, the response is redefined as follows: Table 10. Response When ERR Bit is Set Bit STATUS 7 6 CTS 1 5 XX RESP1 3 2 1 0 RSQINT RDSINT ACFINT STCINT ERROR RESP 1 22 4 Bit Name 7:0 ERROR Rev. 0.9 Function Error definitions. 0x10 = Bad command. 0x11 = Bad ARG1. 0x12 = Bad ARG2. 0x13 = Bad ARG3. 0x14 = Bad ARG4. 0x18 = Command busy. 0x20 = Bad internal memory. 0x30 = Bad patch. 0x31 = Bad boot mode. 0x40 = Bad property. AN543 7.1.1. Common Receiver Commands Command 0x01 POWER_UP The POWER_UP command initiates the boot process to move the device from powerdown to powerup mode. The boot can occur from internal device memory or a system controller downloaded patch. This command powers up the device with the specified function (FM Receive and AM Receive). Power-up is complete when the CTS bit is set. This is the only command that may be sent while the device is powered down. Due to variation of the 4 MHz crystal from vendor to vendor, two power up commands are required for reliably powering up: a 4 MHz crystal preboot POWER_UP command, and a POWER_UP command to boot the part with the desired function (AM, FM). Command Bit 7 6 5 4 00 ARG2 CTSIEN INTSEL FASTBOOT 00 0 XIBIAS[2:0] 0000 FUNC[3:0] ARG4 CTEN[4:0] ARG5 Bit XMODE[2:0] Name 1 7:0 XSTART[7:0] 2 7:6 Reserved Function Oscillator startup 01110101 = 4 MHz crystal pre-boot (first command in 4 MHz crystal sequence) 01110111 = boot (normal operation with external clock, or the second command in a 4 MHz crystal sequence) Always write 00. Selects the amount of additional on-chip capacitance to be connected between XTAL1 and gnd and between XTAL2 and gnd. One half of the capacitance value shown here is the additional load capacitance presented to the xtal. The minimum step size is 0.25 pF. The required value will be layout-dependent. Range is 0-0x3F (i.e. 5-20.75 pF) The EVB sets XCLOAD = 0x27. 2 5:0 XCLOAD[5:0] 3 7 CTSIEN CTS interrupt enable 0 = Disable. 1 = Enable. 3 6 INTSEL CTS interrupt pin select 0 = A1 pin. 1 = INTB pin. 3 5 FASTBOOT 3 4:3 Reserved 3 1 XSTART[7:0] XCLOAD[5:0] ARG1 ARG 2 0x01 CMD ARG3 3 2:0 XBIAS[2:0] Speeds boot time when set. It is required to set this bit with Si475x-A20 and later only. Always write 00. Crystal bias current 3 = 4 MHz crystal or external clock 7 = 4 MHz crystal for boot-up Rev. 0.9 23 AN543 ARG 4 Bit 7:4 Name FUNC[3:0] Function Selects the boot function of the device. 0 = Boot Loader. 1 = FM Receive. 2 = AM Receive. Note: Values other than those listed may result in unpredictable behavior. 4 5 5 24 3:0 7:3 2:0 Reserved Always write 0000. CNTEN[4:0] Enable counter 00000 = 4 MHz crystal pre-boot (first command in 4 MHz crystal sequence) 00010 = boot (normal operation with external clock, or the second command in a 4 MHz crystal sequence) XMODE[2:0] Crystal mode 1 = Crystal 2 = External clock Rev. 0.9 AN543 Command 0x02 PART_INFO The PART_INFO command returns the chip revision, part firmware major, minor, and build revision, and ROM ID. The command is complete when the CTS bit (and optional interrupt) is set. The command may only be sent in powerup mode. Command Bit 7 6 5 4 3 2 1 0 0x02 CMD Response Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT RESP1 CHIPREV[7:0] RESP2 PART[7:0] RESP3 PMAJOR[7:0] RESP4 PMINOR[7:0] RESP5 PBUILD[7:0] RESP6 Reserved RESP7 Reserved RESP8 ROMID[7:0] RESP Bit Name Function 1 7:0 CHIPPREV Chip Revision 2 7:0 PART Part Number, last two digits of part number 3 7:0 PMAJOR Part Major Revision (ASCII Character Value) 4 7:0 PMINOR Part Minor Revision (ASCII Character Value) 5 7:0 PBUILD Part Build Version 6 7:0 Reserved Values may vary. 7 7:0 Reserved Values may vary. 8 7:0 ROMID ROM ID Rev. 0.9 25 AN543 Command 0x11 POWER_DOWN The POWER_DOWN command moves the device from powerup to powerdown mode. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent when in powerup mode. Note that only the POWER_UP command is accepted in powerdown mode. If the system controller writes a command other than POWER_UP when in powerdown mode, the device will not respond. The device will only respond when a POWER_UP command is written. It is possible to power down a device and leave the oscillator running. Command Bit 7 6 5 4 3 2 1 0 0x11 CMD 0000000 ARG1 ARG Bit Name 1 7:1 Reserved 1 0 XOSC XOSC Function Always write 0000000. 0 = Full powerdown. 1 = Powerdown and leave oscillator running. Response Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT Note: The above response shows status bits for FM Receive mode (see Table 8). See Table 9 for status bits for AM Receive mode. 26 Rev. 0.9 AN543 Command 0x12 FUNC_INFO The FUNC_INFO command returns the firmware revision and patch revision for currently-loaded functional mode firmware (AM and FM). The command is complete when the CTS bit (and optional interrupt) is set. This command may only be sent in powerup mode. Command Bit 7 6 5 4 3 2 1 0 0x12 CMD Response Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT RESP1 FWMAJOR[7:0] RESP2 FWMINOR1[7:0] RESP3 FWMINOR2[7:0] RESP4 PATCHH[7:0] RESP5 PATCHL[7:0] RESP6 FUNC[7:0] Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for status bits for AM Receive mode. RESP Bit Name Function 1 7:0 FWMAJOR[7:0] Firmware Major Revision. 2 7:0 FWMINOR1[7:0] Firmware Minor1 Revision. 3 7:0 FWMINOR2[7:0] Firmware Minor2 Revision. 4 7:0 PATCHH[7:0] Patch ID High Byte (HEX). 5 7:0 PATCHL[7:0] Patch ID Low Byte (HEX). 6 7:0 FUNC[7:0] Returns the current functional mode: 1 = FM Receive 2 = AM Receive Rev. 0.9 27 AN543 Command 0x13 SET_PROPERTY The SET_PROPERTY command sets the value of a property. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Command Bit 7 6 5 4 3 CMD 0x13 ARG1 00000000 ARG2 PROPH[7:0] ARG3 PROPL[7:0] ARG4 PROPDH[7:0] ARG5 PROPDL[7:0] 2 1 0 ARG Bit Name Function 1 7:0 Reserved 2 7:0 PROPH [7:0] Property Address High Byte This byte, in combination with PROPL, is used to specify the property to modify. 3 7:0 PROPL [7:0] Property Address Low Byte This byte, in combination with PROPH, is used to specify the property to modify. 4 7:4 PROPDH [7:0] Property Data High Byte This byte, in combination with PROPDL, is used to set the property value. 5 7:0 PROPDL [7:0] Property Data Low Byte This byte, in combination with PROPDH, is used to set the property value. Always write to 0. Response Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for status bits for AM Receive mode. 28 Rev. 0.9 AN543 Command 0x14 GET_PROPERTY The GET_PROPERTY command retrieves a property's value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode Command Bit 7 6 5 4 3 CMD 0x14 ARG1 00000000 ARG2 PROPH[7:0] ARG3 PROPL[7:0] ARG Bit Name 1 7:0 Reserved 2 1 0 Function Always write 0. 2 7:0 PROPH[7:0] Property Address High Byte. This byte, in combination with PROPL, is used to specify the property to get. 3 7:0 PROPL[7:0] Property Address Low Byte. This byte, in combination with PROPH, is used to specify the property to get. Response Bit 7 6 5 STATUS CTS ERR 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT RESP1 XXXXXXXX RESP2 PROPDH[7:0] RESP3 PROPDL[7:0] Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for status bits for AM Receive mode. RESP Bit Name Function 1 7:0 Reserved 2 7:0 PROPDH[7:0] Property Data High Byte. This byte, in combination with PROPDL, represents the requested property value. 3 7:0 PROPDL[7:0] Property Data Low Byte. This byte, in combination with PROPDH, represents Response values may vary. the requested property value. Rev. 0.9 29 AN543 Command 0x15 GET_INT_STATUS The GET_INT_STATUS command updates the bits of the status byte. This command should be called after any command that sets the STCINT, ACFINT, RDSINT, ASQINT, or RSQINT bits. When polling, this command should be periodically called to monitor the STATUS byte, and, when using interrupts, this command should be called after the interrupt is set to update the STATUS byte. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be set in powerup mode. Command Bit 7 6 5 4 3 2 1 0 0x15 CMD Response Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for status bits for AM Receive mode. Command 0x17 AGC_STATUS The AGC_STATUS command reports the current status of the AGC for FM mode. AM_AGC_STATUS (command 0x47) is used in AM/LW/SW modes. The command is complete when the CTS bit (and optional interrupt) is set. This command may only be sent when in powerup mode. Bit 7 6 5 4 2 1 0 3 2 1 0 RSQINT RDSINT ACFINT STCINT LNAHI LNALO X X 0x17 CMD RESP 7 6 STATUS CTS ERR RESP1 3 XX 5 4 XX MIXHI MIXLO RESP2 FMAGC1 RESP3 FMAGC2 RESP4 PGAGAIN RESP5 FMLNAG Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for status bits for AM Receive mode. 30 Rev. 0.9 AN543 RESP Bit Name 1 7:6 Reserved 1 5 MIXHI 0 = FM Mixer PD high threshold is not tripped. 1 = FM Mixer PD high threshold is tripped. 1 4 MIXLO 0 = FM Mixer PD low threshold is not tripped. 1 = FM Mixer PD low threshold is tripped. 1 3 LNAHI 0 = FM LNA PD high threshold is not tripped. 1 = FM LNA PD high threshold is tripped. 1 2 LNALO 0 = FM LNA PD low threshold is not tripped. 1 = FM LNA PD low threshold is tripped. 1 1:0 Reserved Values may vary. FMAGC1 The parallel combination of these resistors indicates the current FMAGC1 attenuator resistance. The total resistance value at the pin is 800/FMAGC1. 0 = 10 k--no attenuation 1 = 800 2 = 400 4 = 200 8 = 100 16 = 50 32 = 25 64 = 12.5 128 = 6.25 2 7:0 Function Values may vary. 3 7:0 FMAGC2 The parallel combination of these resistors indicates the current FMAGC2 attenuator resistance. The total resistance value at the pin is 800/FMAGC2. 0 = 10 k--no attenuation 1 = 800 2 = 400 4 = 200 8 = 100 16 = 50 32 = 25 64 = 12.5 128 = 6.25 4 7:0 PGAGAIN PGA gain in dB Range: 8-33 5 7:0 FMLNAG FM LNA Gain in dB Range: 2-14 Rev. 0.9 31 AN543 Command 0x1B ANA_AUDIO_PIN_CFG The ANA_AUDIO_PIN_CFG command configures the analog audio pins. Writing an argument byte to 0 will not change the state of the pin and is useful when using this command to query the state of the pins. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Note: Available in Si475x-A20 and later only. Command Bit 7 6 5 4 2 1 0 0x1B CMD ARG1 0 ARG Bit Name 1 7 Reserved 1 3 LROUT[6:0] 6:0 Function Always write 0. LROUT[6:0] 0 = Do not modify the behavior of this pin. 1 = Disable the output drivers, so the pins are completely inactive and can be left floating. 2 = Configure the LOUT/ROUT pins to output audio. 3 = Configure LOUT for MPX and disable ROUT (Si4755/57 only). Response Bit 7 6 STATUS CTS ERR RESP1 X 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT LROUT[6:0] Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for status bits for AM Receive mode. RESP Bit Name 1 7 Reserved 1 32 6:0 LROUT[6:0] Function Values may vary. 1 = The output drivers are disabled, so the pins are completely inactive and can be left floating. 2 = LOUT/ROUT pins configured to output audio. 3 = LOUT is configured for MPX out (Si4755/57 only) and ROUT is disabled. Rev. 0.9 AN543 Command 0x1C INTB_PIN_CFG The INTB_PIN_CFG command configures INTB and A1 pins. Writing an argument byte to 0 will not change the state of the pin and is useful when using this command to query the state of the pins. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Command Bit 7 6 5 4 3 2 1 0 0x1C CMD ARG1 0 INTB[6:0] ARG2 0 A1[6:0] ARG Bit Name Function 1 7 Reserved Always write to 0. 1 6:0 INTB[6:0] 0 = Do not modify the behavior of this pin. 1 = Disable both the output and input drivers so the pin is completely inactive and can be left floating. 40 = Configure this pin as the interrupt. 2 7 Reserved Always write to 0. 2 6:0 0 = Do not modify the behavior of this pin. 1 = Disable both the output and input drivers so the pin is completely inactive and can be left floating. 40 = Configure this pin as the interrupt. A1[6:0] Response Bit 7 6 5 4 Status CTS ERR RESP1 X INTB[6:0] RESP 2 X A1[6:0] xx 3 2 1 0 RSQINT RDSINT ACFINT STCINT Note: The above response shows status bits for FM Receive mode (see Table 8 on page 20). See Table 9 on page 21 for status bits for AM Receive mode. RESP Bit Name Function 1 7 Reserved Values may vary. 1 6:0 INTB[6:0] 1 = Disabled. 40 = Configured as the interrupt. 2 7 Reserved Values may vary. 2 6:0 A1[6:0] 1 = Disabled. 40 = Configured as the interrupt. Rev. 0.9 33 AN543 7.1.2. Common Receiver Properties Property 0x0000 INT_CTL_ENABLE The INT_CTL_ENABLE property enables top-level interrupt sources. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x0000 INT_CTL_ENABLE 15 14 13 0000 0000 34 12 11 10 9 8 7 6 5 RSQREP RDSREP ACFREP STCREP CTSIEN ERRIEN 0 0 0 0 0 0 4 00 00 3 2 1 0 RSQIEN RDSIEN ACFIEN STCIEN 0 0 0 0 Bit Name Function 15:12 Reserved Always write 0. 11 RSQREP Repeat interrupt pulse when RSQINT is set, even if a previous interrupt was generated but not acknowledged. 10 RDSREP Repeat interrupt pulse when RDSINT is set, even if a previous interrupt was generated but not acknowledged. 9 ACFREP Repeat interrupt pulse when ACFINT is set, even if a previous interrupt was generated but not acknowledged. 8 STCREP Repeat interrupt pulse when STCIEN is set, even if a previous interrupt was generated but not acknowledged. 7 CTSIEN Interrupt when CTS is set. 6 ERRIEN Interrupt when ERR is set. 5:4 Reserved Always write 0. 3 RSQIEN Interrupt when RSQIEN is set. 2 RDSIEN Interrupt when RDSINT is set. 1 ACFIEN Interrupt when ACFINT is set. 0 STCIEN Interrupt when STCIEN is set. Rev. 0.9 AN543 Property 0x0300 AUDIO_ANALOG_VOLUME The AUDIO_ANALOG_VOLUME property sets the analog audio volume. A value of 0 will mute the audio; a value of 1 applies 62 dB of attenuation, and a value of 63 applies no attenuation. Each step accounts for 1 dB of change in the output. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 63 AUDIO_ANALOG_VOLUME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x000 VOL[5:0] 0x000 0x3F Bit Name 15:6 Reserved Always write 0. 5:0 VOL[5:0] Sets the analog audio volume. Default is 63. Range is 0-63. 1 0 Function Property 0x0301 AUDIO_MUTE The AUDIO_MUTE property mutes/unmutes each audio output (analog left or analog right).The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Default: 0x0000 AUDIO_MUTE 15 14 13 12 11 10 Bit Name 15:2 Reserved 1 RIGHTMUTE 0 LEFTMUTE 9 8 7 6 5 4 3 2 1 0 0x0000 RIGHTMUTE LEFTMUTE 0x0000 0 0 Function Always write 0. 0 = Right audio is not muted. 1 = Right audio is muted. 0 = Left audio is not muted. 1 = Left audio is muted. Rev. 0.9 35 AN543 7.2. Commands and Properties for FM Receiver Table 11. FM Receiver Command Summary Number Name 0x30 FM_TUNE_FREQ Tunes the FM receiver to a frequency in 10 kHz steps. 0x31 FM_SEEK_START Initiates a seek for a channel that meets the validation criteria for FM. 0x32 FM_RSQ_STATUS Returns status information about the received signal quality. 0x35 FM_ACF_STATUS Returns status information about automatically-controlled features for the tuned station. 0x36 FM_RDS_STATUS Returns RDS information for current channel and reads an entry from the RDS FIFO (Si4751/53/55/57 only). 0x37 FM_RDS_BLOCKCOUNT 36 Summary Returns RDS expected, received, and uncorrectable block statistic information (Si4751/53/55/57 only). Rev. 0.9 AN543 Table 12. FM Receiver Properties Summary Address Name Default Summary A10 A20 A30 A40 A55 0x0000 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0 0x0008 0x0008 0x0008 0x0008 8 8 8 8 0x0008 0x0008 0x0008 0x0008 8 8 8 8 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x01F4 0x01F4 0x01F4 0x01F4 500 500 500 500 0x0078 0x0078 0x0078 0x0078 120 120 120 120 0x0080 0x0080 128 128 0x0008 0x0008 8 8 0x0000 0x0000 0 0 0x01F4 0x01F4 500 500 0x0078 0x0078 120 120 0x0302 AUDIO_DE_EMPHASIS 0x0400 FM_SOFT_MUTE_MAX_ATTENUATION 0x0401 FM_SOFT_MUTE_TRIGGER_THRESHOLD 0x0402 FM_SOFT_MUTE_END_THRESHOLD 0x0403 FM_SOFT_MUTE_RELEASE_TIME 0x0404 FM_SOFT_MUTE_ATTACK_TIME 0x0405 FM_SOFT_MUTE_MAX_ATTENUATION_AGC N/A N/A 0x0406 FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC N/A N/A 0x0407 FM_SOFT_MUTE_END_THRESHOLD_AGC N/A N/A 0x0408 FM_SOFT_MUTE_RELEASE_TIME_AGC N/A N/A 0x0409 FM_SOFT_MUTE_ATTACK_TIME_AGC N/A N/A 0x040A FM_SOFT_MUTE_USN_LIMITS N/A N/A Rev. 0.9 0x060E 1550 N/A Sets the FM Receive de-emphasis. 0x0008 Sets the maximum soft mute attenuation for RSSI/SNR softmute engine. 8 0x0002 Sets the trigger threshold for RSSI/SNR softmute engine. 2 0x00FA Sets the end threshold for RSSI/SNR softmute engine. -6 0x01F4 Sets the maximum soft mute release time in ms for RSSI/SNR softmute engine. 500 0x0078 Sets the maximum soft mute attack time in ms for RSSI/SNR softmute engine. 120 0x0080 Sets the maximum soft mute attenuation for RSSI/SNR+AGC softmute engine. 128 0x0008 Sets the trigger threshold for RSSI/ SNR+AGC softmute engine. 8 0x0000 Sets the end threshold for RSSI/SNR+AGC softmute engine. 0 0x01F4 Sets the maximum soft mute release time in ms for RSSI/SNR+AGC softmute engine. 500 0x0078 Sets the maximum soft mute attack time in ms for RSSI/SNR+AGC softmute engine. 120 N/A Set the limits for the USN input metric on the soft mute mitigation engine. 37 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name Default A10 A20 0x040B FM_SOFT_MUTE_USN_ATTENUATION N/A N/A 0x040C FM_SOFT_MUTE_USN_ATTACK_TIME N/A N/A 0x040D FM_SOFT_MUTE_USN_RELEASE_TIME N/A N/A 0x040E FM_SOFT_MUTE_ASSI200_DEV_LIMITS N/A N/A 0x040F FM_SOFT_MUTE_ASSI200_DEV_ATTENUATION N/A N/A 0x0410 FM_SOFT_MUTE_ASSI200_DEV_ATTACK_TIME N/A N/A 0x0411 FM_SOFT_MUTE_ASSI200_DEV_RELEASE_TIME N/A N/A 0x0700 FM_AGC_FE_CONFIG 0x0080 0x0701 FM_AGC_PD_CONFIG 0x0702 38 A30 0x0000 0 0x0080 128 0x0100 256 Summary A40 A55 N/A N/A Set the limits for the attenuation when driven by USN on the soft mute mitigation engine. N/A N/A USN-based soft mute attack time in ms. N/A N/A USN-based soft mute release time in ms. 0x335A 0x335A 13146 13146 0x0000 0x0000 0 0 0x0080 0x0080 128 128 0x100 0x100 0x100 256 256 256 0x0080 0x0080 0x0080 128 128 128 128 0x0270 0x0270 0x0270 0x0270 624 624 624 624 0x0004 0x0004 0x0004 0x0004 4 4 4 4 FM_LNA_AGC_ATTACK_MS Rev. 0.9 0x335A Sets the trigger and end thresholds for 13146 ASSI200DEV softmute engine. 0x0000 Sets the maximum soft mute attenuation for ASSI200DEV softmute engine. 0 0x0080 Sets the maximum soft mute release time in ms for ASSI200DEV softmute engine. 128 Sets the maximum soft mute attack time in ms for ASSI200DEV softmute engine. 0x0080 Specified the input path for RF signal and other FE configuration options. 128 0x0270 Specifies the behavior of the FM peak detectors and attenuators. 624 0x0004 Sets the number of milliseconds the wideband RF high-peak detector must be exceeded before attenuating the appropri4 ate block. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x0703 FM_LNA_AGC_RELEASE_MS 0x0704 FM_LNA_AGC_PD_THRESHOLD 0x0705 FM_MIXER_AGC_ATTACK_MS Default Summary A10 A20 A30 A40 0x0050 0x0050 0x0050 0x0050 80 80 80 80 0x4F05 0x4F05 0x4F05 0x4F05 20229 20229 20229 20229 0x0004 0x0004 0x0004 0x0004 4 4 4 4 0x0050 0x0050 0x0050 0x0050 80 80 80 80 0x5103 0x5103 0x5103 0x5103 20739 20739 20739 20739 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0 0 0 0x0055 0x0055 85 85 0x140E 0x140E 5134 5134 0x0050 0x0050 80 80 0x0050 0x0050 80 80 0x0706 FM_MIXER_AGC_RELEASE_MS 0x0707 FM_MIXER_AGC_PD_THRESHOLD 0x0710 FM_AGC_OVERRIDE 0x071B FM_AGC_RSSI_OFFSET N/A 0x071C FM_MIXER_AGC_PD_THRESHOLD_MAX N/A N/A 0x071D FM_AGC_RSSI_MIXER_KEY N/A N/A 0x1006 FM_SEEK_TUNE_CHBW_HOLD_TIME N/A Do not Write 0x1007 FM_TUNE_CHBW N/A N/A Rev. 0.9 A55 0x0050 Sets the number of milliseconds the wideband RF low-peak detector must not be 80 exceeded before increasing the gain of the 0x4F05 Sets the high threshold and hysteresis for 20229 the LNA peak detector. 0x00F8 Sets the number of milliseconds the wideband mixer high-peak detector must be exceeded before attenuating the appropri248 ate block. 0x0050 Sets the number of milliseconds the wideband mixer low-peak detector must not be exceeded before increasing the gain of the 80 appropriate block. 0x5103 Sets the high threshold and hysteresis for 20739 the mixer peak detector. 0x0000 Overrides the AGC setting by disabling the AGC and forcing the gain to be maximum. 0 0x0000 Offsets the RSSI value so that it can take into account front-end gain/loss. 0 0x0059 Sets the maximum threshold for the mixer peak detector. 89 0x140E Sets the RSSI threshold and hysteresis to 5134 enable keyed AGC. 0x0050 Sets the length of time CHBW is held in unit of ms. 80 0x0050 Sets the maximum CHBW allowed during the normal tune. 80 39 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x1008 FM_TUNE_AF_CHBW 0x1100 FM_SEEK_BAND_BOTTOM 0x1101 FM_SEEK_BAND_TOP 0x1102 FM_SEEK_FREQUENCY_SPACING 0x1104 FM_SEEK_CHBW 0x1200 FM_RSQ_INTERRUPT_SOURCE 0x1201 FM_RSQ_SNR_HIGH_THRESHOLD 0x1202 FM_RSQ_SNR_LOW_THRESHOLD 0x1203 FM_RSQ_RSSI_HIGH_THRESHOLD 0x1204 FM_RSQ_RSSI_LOW_THRESHOLD 0x1205 FM_RSQ_ISSI_HIGH_THRESHOLD 40 Default A10 A20 N/A N/A 0x222E Summary A30 A40 A55 0x0096 0x0096 0x0096 150 150 80 0x222E 0x222E 0x222E 8750 8750 8750 8750 0x2A26 0x2A26 0x2A26 0x2A26 10790 10790 10790 10790 0x000A 0x000A 0x000A 0x000A 10 10 10 10 N/A N/A 0x006E 0x006E 0x0050 110 110 80 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x007F 0x007F 0x007F 0x007F 127 127 127 127 0xFF80 0xFF80 0xFF80 0xFF80 -128 -128 -128 -128 0x007F 0x007F 0x007F 0x007F 127 127 127 127 0xFF80 0xFF80 0xFF80 0xFF80 -128 -128 -128 -128 0x007F 0x007F 0x007F 0x007F 127 127 127 127 Rev. 0.9 Sets the CHBW during the AF tune/check. 0x222E Sets the lower seek boundary of the FM 8750 band in multiples of 10 kHz. 0x2A30 Sets the upper seek boundary for the FM 10800 band in multiples of 10 kHz. 0x000A Sets the frequency spacing for the FM band in multiples of 10 kHz when performing a 10 seek. Sets the CHBW during the seek. 0x0000 Configures interrupt related to Received Signal Quality metrics (FM_RSQ_STA0 TUS). 0x007F Sets high threshold which triggers the RSQ interrupt if the SNR is above this threshold. 127 0xFF80 Sets low threshold which triggers the RSQ -128 interrupt if the SNR is below this threshold. 0x007F Sets high threshold which triggers the RSQ interrupt if the RSSI is above this threshold. 127 0xFF80 Sets low threshold which triggers the RSQ -128 interrupt if the RSSI is below this threshold. 0x007F Sets high threshold, which triggers the RSQ interrupt if image signal strength is above 127 this threshold. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x1206 FM_RSQ_ISSI_LOW_THRESHOLD 0x1207 FM_RSQ_MULTIPATH_HIGH_THRESHOLD 0x1208 FM_RSQ_MULTIPATH_LOW_THRESHOLD 0x1300 FM_ACF_INTERRUPT_SOURCE 0x1301 FM_ACF_SM_THRESHOLD 0x1302 FM_ACF_CHBW_THRESHOLD 0x1303 FM_ACF_HICUT_THRESHOLD 0x1304 FM_ACF_HIBLEND_THRESHOLD 0x1305 FM_ACF_BLEND_THRESHOLD 0x1306 FM_ACF_CONTROL_SOURCE 0x1307 FM_ACF_HOLD_TIME 0x2000 FM_VALID_MAX_TUNE_ERROR Default Summary A10 A20 A30 A40 0xFF80 0xFF80 0xFF80 0xFF80 -128 -128 -128 -128 0x007F 0x007F 0x007F 0x007F 127 127 127 127 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0 0x001F 0x001F 0x001F 0x001F 0x001F 31 31 31 31 31 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0001 0x0001 0x0001 0x0001 1 1 1 1 N/A N/A N/A N/A 0x004B 0x004B 0x004B 0x004B 75 75 75 75 Rev. 0.9 A55 0xFF80 Sets low threshold which triggers the RSQ interrupt if image signal strength is below -128 this threshold. 0x007F Sets high threshold which triggers the RSQ interrupt if Multipath is above this threshold. 127 0x0000 Sets low threshold which triggers the RSQ interrupt if Multipath is below this threshold. 0 Enables the ACF interrupt sources. Sets the softmute interrupt threshold in dB. 0x0000 Sets the Channel Filter Bandwidth interrupt threshold in units of kHz. 0 0x0000 Sets the HICUT interrupt threshold in units of 100 Hz. 0 0x0000 Sets the HIBLEND interrupt threshold in units of 100 Hz. 0 0x0000 Sets the Stereo Blend interrupt threshold in units of percent L-R gain. 0 0x0003 Sets the controlling metric for ACF features. 3 0x0064 100 Sets the ACF hold time after tune. 0x004B Sets the maximum frequency error in 2 ppm allowed before setting the AFCRL indi75 cator. 41 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x2001 FM_VALID_RSSI_TIME 0x2002 FM_VALID_SNR_TIME 0x2003 FM_VALID_SNR_THRESHOLD 0x2004 FM_VALID_RSSI_THRESHOLD 0x2005 Default Summary A10 A20 A30 A40 0x0006 0x0006 0x0006 0x0006 6 6 6 6 0x0012 0x0012 0x0012 0x0012 18 18 18 18 0x0008 0x0008 0x0008 0x0008 8 8 8 8 0x000C 0x000C 0x000C 0x000C A55 0x0006 Sets the amount of time in milliseconds to allow the RSSI metric to settle before eval6 uating. 0x0012 Sets the amount of time in milliseconds to allow the SNR metric to settle before evalu18 ating. 0x0008 Sets the SNR threshold for a valid FM Seek Tune. 8 0x000C Sets the RSSI threshold for a valid FM Seek Tune. 12 12 12 12 12 FM_VALID_ISSI_THRESHOLD Do not write Do not write 0x001E 0x001E 30 30 0x2006 FM_VALID_MULT_THRESHOLD N/Z 0x0064 0x0064 0x0064 100 100 100 0x0005 0x0005 0x0002 0x2007 FM_VALID_AF_TIME N/A 5 5 2 0x0078 0x0078 0x2008 FM_VALID_AF_RDS_TIME N/A N/A 120 120 0x2009 FM_VALID_AF_PI N/A N/A 0x0000 0x0000 0x0000 0 0 0 0x200A FM_VALID_ASSI_THRESHOLD N/A N/A 0x503C 0x503C 20540 20540 0x200B FM_VALID_AF_PI_MASK N/A N/A 0xFFFF 0xFFFF 65535 65535 42 Rev. 0.9 0x001E Sets the ISSI threshold for injection side switch during FM Seek Tune. 30 0x0064 Sets the multipath threshold for a valid FM Seek/Tune. 100 0x0002 Sets the amount of time in milliseconds to allow the RSSI and SNR metrics to settle 2 before evaluating during an AF check/tune. 0x0078 Sets the amount of time in milliseconds to allow the PI code to be captured before 120 evaluating. Sets the PI code to match during AF tune. 0x503C Sets the ASSI/ASSI200 threshold for valid 20540 FM Seek/Tune. 0xFFFF Sets the mask on PI code match during AF 65535 tune. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name Default A10 A20 A30 Summary A40 0x0000 A55 0x0000 Changes FREQOFF from bppm units to some multiple of Hz. 0 0x200C FM_VALID_FREQOFF_SCALE N/A N/A N/A 0x200D FM_VALID_FREQOFF_FILTER N/A N/A N/A 0x2100 FM_NB_DETECT_THRESHOLD 0x0012 0x0012 0x0012 0x0012 18 18 18 18 0x2101 FM_NB_INTERVAL 0x0005 0x0005 0x0005 0x0005 5 5 5 5 0x2103 FM_NB_SECONDARY_DETECT_THRESHOLD N/A N/A N/A N/A 0x2105 FM_NB_WEAK_DETECT_THRESHOLD N/A N/A 0x3500 0x3500 13568 13568 0x0032 0x0032 0x0032 0x0032 0x2106 FM_NB_STRONG_SIGNAL_SHUTOFF 50 50 50 50 0x0000 0x0000 0x0000 0x2109 FM_NB_MODE_CONTROL N/A N/A 0 0 0 0x0005 0x0005 0x0005 0x210A FM_NB_WEAK_BLANK_INTERVAL N/A N/A 5 5 5 0x210B FM_NB_STRONG_WEAK_SWITCH N/A N/A 0x0B09 0x0B09 2825 2825 0x2111 FM_NB_CIMP_HICUT_LIMIT N/A N/A N/A N/A Rev. 0.9 0 0x0064 100 0x0064 Changes the amount that FREQOFF is filtered. 100 0x0012 Sets the threshold for detecting impulses in dB above the noise floor. 18 0x0005 Sets the interval that original samples are replaced by interpolated clean samples. 5 0x0000 Sets the threshold for detecting impulses in percentage of average to peak 0 0x1D71 Sets the threshold for detecting impulses 7537 with the weak signal noise blanker. 0x0023 The RSSI based shutoff threshold. Used to turn off the noise blanker under strong sig35 nal conditions. Sets options of the noise blankers. Number of samples that are replaced by interpolated clean samples. 0x0B09 Sets the SNR/RSSI thresholds for determining whether strong or weak blanker is 2825 used. 0x0A14 Sets the HiCut multipath threshold when 2580 continuous impulses are detected. 43 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name Default Summary A10 A20 A30 A40 A55 0x2112 FM_NB_CIMP_HICUT_FREQ N/A N/A N/A N/A 0x6401 Sets the HiCut cut-off frequency when con25601 tinuous impulses are detected. 0x2113 FM_NB_CIMP_HICUT_ATTACK N/A N/A N/A N/A 0x0001 Sets the HiCut attack time when continuous impulses are detected. 1 0x2114 FM_NB_CIMP_HICUT_RELEASE N/A N/A N/A N/A 0x0008 Sets the HiCut release time when continuous impulses are detected. 8 0x2115 FM_NB_CIMP_DETCNTR N/A N/A N/A N/A 0x0402 Continuous impulse detection counter set1026 ting. 0x2116 FM_NB_CIMP_A2PTH N/A N/A N/A N/A 0x0800 Independent IQ impulse detection thresh2048 old for continuous impulse detection. 0x2117 FM_NB_CIMP_IMPDET N/A N/A N/A N/A 0x400A Aggressive noise blanker impulse detection threshold when continuous impulses 16394 detected. 0x2118 FM_NB_CIMP_MPX_INTV N/A N/A N/A N/A 0x0A0A Aggressive MPX blanker interval when continuous impulses detected replacing 2570 property 0x2101. 0x9637 0x9637 0x9637 0x9637 38455 38455 38455 38455 0x000C 0x000C 12 12 0x2200 FM_CHBW_SQ_MIN_MAX 0x2201 FM_CHBW_SQ_HIGH_THRESHOLD 0x2202 FM_CHBW_SQ_LOW_THRESHOLD 0x2203 FM_CHBW_SQ_WIDENING_TIME 0x000C 0x000C 12 12 0xFFFC 0xFFFC 0xFFFC 0xFFFC 44 -4 -4 -4 -4 0x0010 0x0010 0x0010 0x0010 16 16 16 16 Rev. 0.9 0x9637 Sets the maximum and minimum channel filter bandwidth in units of kHz based on 38455 RSSI/STRONGDEV (or SNR) in weak signal condition. 0x000C Sets the RSSI/STRONGDEV (or SNR) threshold for maximum channel filter band12 width in weak signal condition. 0x0002 Sets the RSSI/STRONGDEV (or SNR) threshold for minimum channel filter band2 width in weak signal condition. 0x0010 Sets the channel filter bandwidth widening time based on RSSI/STRONGDEV (or 16 SNR) in weak signal condition. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x2204 FM_CHBW_SQ_NARROWING_TIME 0x2205 FM_CHBW_ASSI_MIN_MAX 0x2206 FM_CHBW_ASSI_LOW_THRESHOLD 0x2207 FM_CHBW_ASSI_HIGH_THRESHOLD 0x2208 FM_CHBW_ASSI_WIDENING_TIME 0x2209 FM_CHBW_ASSI_NARROWING_TIME 0x220A FM_CHBW_ASSI200_MIN_MAX 0x220B FM_CHBW_ASSI200_LOW_THRESHOLD 0x220C FM_CHBW_ASSI200_HIGH_THRESHOLD 0x220D FM_CHBW_ASSI200_WIDENING_TIME 0x220E FM_CHBW_ASSI200_NARROWING_TIME 0x220F FM_CHBW_WEAKSIG_THR Default Summary A10 A20 A30 A40 0x0800 0x0800 0x0800 0x0800 2048 2048 2048 2048 0x9623 0x9623 0x9623 0x9623 38435 38435 38435 38435 0x0007 0x0007 0x0007 0x0007 7 7 7 7 0x0014 0x0014 0x0014 0x0014 20 20 20 20 0x0001 0x0001 0x0C80 0x0C80 1 1 3200 3200 0x0140 0x0140 0x0140 0x0140 320 320 320 320 0x9632 0x9650 0x9650 0x9650 38450 38480 38480 38480 0xFFF6 0xFFF6 0xFFF6 0xFFF6 A55 0x0800 Sets the channel filter bandwidth narrowing time based on RSSI/STRONGDEV (or 2048 SNR) in weak signal condition. 0x9623 Sets the delta (HASSI,LASSI) threshold for maximum and minimum channel filter 38435 bandwidth in units of kHz. 0x0007 Sets the delta (HASSI,LASSI) threshold for 7 0x0014 Sets the delta (HASSI,LASSI) threshold for minimum channel filter bandwidth. 20 0x0C80 Sets the channel filter bandwidth widening 3200 time based on the delta (HASSI,LASSI). 0x0140 Sets the channel filter bandwidth narrowing time based on the delta (HASSI,LASSI). 320 0x964B Sets the ASSI200 maximum and minimum 38475 channel filter bandwidth in units of kHz. 0x0000 Sets the ASSI200 threshold for maximum channel filter bandwidth. 0 -10 -10 -10 -10 0x000A 0x000A 0x000A 0x000A 10 10 10 10 0x0001 0x0001 0xC80 0xC80 0xFA0 1 1 3200 3200 4000 0x0140 0x0140 0x0140 0x0140 320 320 320 320 0x100D 0x100D 0x100D 4109 4109 4109 N/A Rev. 0.9 maximum channel filter bandwidth 0x000A Sets the ASSI200 threshold for minimum channel filter bandwidth. 10 Sets the channel filter bandwidth widening time based on ASSI200. 0x0140 Sets the channel filter bandwidth narrowing time based on ASSI200. 320 0x100D Sets the hysteresis window for the weak 4109 signal channel filter bandwidth engine. 45 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name Default A10 A20 A30 A40 0x140A 0x140A 5130 5130 0x0000 0x0200 0 512 0x9680 0x9680 0x9680 38528 38528 38528 0x0008 0x0008 0x0008 8 8 8 0x0013 0x0013 0x0013 19 19 19 0x1000 0x1000 0x1000 4096 4096 4096 0x0200 0x0200 0x0200 512 512 512 0x5020 0x9646 20512 38470 0x0032 0x0032 50 50 0x005A 0x005A 90 90 0x0800 0x0800 2048 2048 0x2210 FM_CHBW_BLOCKER_THR N/A Do not Write 0x2214 FM_CHBW_ASSI_B_CONTROL N/A N/A 0x2215 FM_CHBW_STRONGDEV_MIN_MAX N/A 0x2216 FM_CHBW_STRONGDEV_LOW_THRESHOLD N/A 0x2217 FM_CHBW_STRONGDEV_HIGH_THRESHOLD N/A 0x2218 FM_CHBW_STRONGDEV_WIDENING_TIME N/A 0x2219 FM_CHBW_STRONGDEV_NARROWING_TIME N/A 0x221A FM_CHBW_ASSI200DEV_MIN_MAX N/A N/A 0x221B FM_CHBW_ASSI200DEV_LOW_THRESHOLD N/A N/A 0x221C FM_CHBW_ASSI200DEV_HIGH_THRESHOLD N/A N/A 0x221D FM_CHBW_ASSI200DEV_WIDENING_TIME N/A N/A 46 Summary Rev. 0.9 A55 0x140A Sets the threshold and hysteresis to enable channel filter bandwidth based on 5130 ASSI200DEV. 0x0200 Selects the behavior of ASSI-B channel filter bandwidth control engine. 512 0x9664 Sets the maximum and minimum channel filter bandwidth in units of kHz based on 38500 STRONGDEV. 0x0008 Sets the STRONGDEV threshold for maximum channel filter bandwidth. 8 0x0013 Sets the STRONGDEV threshold for minimum channel filter bandwidth. 19 0x1000 Sets the channel filter bandwidth widening 4096 time based on STRONGDEV. 0x0200 Sets the channel filter bandwidth narrowing time based on STRONGDEV. 512 0x9646 Sets the maximum and minimum channel filter bandwidth in units of kHz based on 38470 ASSI200DEV. 0x0032 Sets the ASSI200DEV threshold for maximum channel filter bandwidth. 50 0x005A Sets the ASSI200DEV threshold for minimum channel filter bandwidth. 90 0x0800 Sets the channel filter bandwidth widening 2048 time based on ASSI200DEV. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name Default A10 A20 Summary A30 A40 A55 0x0080 0x0080 128 128 0x9696 0x9696 38550 38550 0x0000 0x0000 0 0 0x0000 0x0000 0 0 0x0001 0x0001 1 1 0x0001 0x0001 1 1 0x0000 0x0000 0x0000 0 0 0 0x0000 0x0000 0 0 0x0080 Sets the channel filter bandwidth narrowing time based on ASSI200DEV. 128 0x221E FM_CHBW_ASSI200DEV_NARROWING_TIME N/A N/A 0x221F FM_CHBW_ASSI_B_MIN_MAX N/A N/A 0x2220 FM_CHBW_ASSI_B_LOW_THRESHOLD N/A N/A 0x2221 FM_CHBW_ASSI_B_HIGH_THRESHOLD N/A N/A 0x2222 FM_CHBW_ASSI_B_WIDENING_TIME N/A N/A 0x2223 FM_CHBW_ASSI_B_NARROWING_TIME N/A N/A 0x3105 FM_LOWCUT_MIN_FREQ Do Not Write N/A 0x3106 FM_LOWCUT_MAX_FREQ Do Not Write N/A 0x3200 FM_POP_NOISE_FADE_HYST Do not Write Do not Write 0x0A06 0x0A06 2566 2566 0x3207 FM_POP_NOISE_MODE 0x0001 0x0001 0x0001 0x0001 0x0002 1 1 1 1 2 0x3208 FM_POP_NOISE_RSSI_THRESHOLDS N/A 0x9696 Sets the maximum and minimum channel filter bandwidth in units of kHz based on 38550 max (HASSI,LASSI). 0xFFFB Sets the max (HASSI,LASSI) threshold for maximum channel filter bandwidth. -5 0x0005 Sets the max (HASSI,LASSI) threshold for minimum channel filter bandwidth. 5 0x0FA0 Sets the channel filter bandwidth widening 4000 time based on max (HASSI,LASSI). 0x0190 Sets the channel filter bandwidth narrowing time based on max (HASSI,LASSI). 400 Sets the minimum LowCut cutoff frequency. 0x0000 Sets the maximum LowCut cutoff frequency. 0 0x0604 Sets the thresholds for FM pop filter fading 1540 hysteresis Sets the pop mitigation mode. 0xECE7 0xECE7 0xECE7 0xFDF9 Sets the change in RSSI thresholds for maximum and minimum MPX limiting (set 60647 60647 60647 65017 by property 0x3209). Rev. 0.9 47 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name Default A10 A20 A30 A40 0x1009 0x1009 0x1009 4105 4105 4105 0x0001 0x0001 0x0001 1 1 1 0x0001 0x0001 0x0001 0x0BB8 1 1 1 3000 0x03FE 0x03FE 0x03FE 1022 1022 1022 0x1009 0x1009 0x1009 4105 4105 4105 0x0001 0x0001 0x0001 1 1 1 0x0001 0x0001 0x0001 0x0BB8 1 1 1 3000 0x007F 0x007F 0x007F 0x007F 0x007F 127 127 127 127 127 0x0601 0x0601 0x8001 1537 1537 32769 0x3209 FM_POP_NOISE_RSSI_MPX_LIMIT N/A 0x320A FM_POP_NOISE_RSSI_MPX_ATTACK N/A 0x320B FM_POP_NOISE_RSSI_MPX_RELEASE N/A 0x320C FM_POP_NOISE_MPX_USN_THRESHOLDS N/A 0x320D FM_POP_NOISE_MPX_USN_LIMITS N/A 0x320E FM_POP_NOISE_MPX_USN_ATTACK N/A 0x320F FM_POP_NOISE_MPX_USN_RELEASE N/A 0x3210 FM_POP_NOISE_SCALE 0x3400 FM_MULT_EQ_CTL N/A N/A 0x3401 FM_MULT_EQ_NOISE_DISABLE N/A N/A 0x3402 FM_MULT_EQ_CTL_STEP N/A N/A 0x3409 FM_EQ_CTL_AUTOTAP N/A N/A 48 Summary Rev. 0.9 A55 0x0502 Sets the minimum and maximum limit for 1282 MPX limiter based on change in RSSI. 0x001E Sets the attack rate for MPX limiter pop mitigation. 30 Sets the release rate for pop mitigation. 0x0501 Sets the ratio of MPX to USN thresholds for maximum and minimum MPX limiting (set 1281 by property 0x320D). 0x0502 Sets the maximum and minimum limit for 1282 MPX limiter based on ratio of MPX to USN. 0x001E Sets the attack rate for MPX limiter pop mitigation. 30 Sets the release rate for pop mitigation. Sets the scale for the FM pop filter. Controls the multipath channel equalizer. 0xFC81 0xFCFA 0xFCFA Sets the RSSI threshold below which the channel equalizer will use noise measure64641 64762 64762 ment to enable/disable channel equalizer. 0x0000 0x0000 0 0 N/A N/A 0x0000 Sets the channel equalizer tap updating rate. 0 0x03FB Sets the threshold for channel equalizer 1019 auto tap control. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x3500 FM_BLEND_RSSI_THRESHOLDS 0x3501 FM_BLEND_RSSI_STEREO_SEP 0x3502 FM_BLEND_RSSI_ATTACK_TIME 0x3503 FM_BLEND_RSSI_RELEASE_TIME 0x3508 FM_BLEND_MULTIPATH_THRESHOLDS 0x3509 FM_BLEND_MULTIPATH_STEREO_SEP 0x350A FM_BLEND_MULTIPATH_ATTACK_TIME 0x350B FM_BLEND_MULTIPATH_RELEASE_TIME 0x3510 FM_BLEND_USN_THRESHOLDS 0x3511 FM_BLEND_USN_STEREO_SEP 0x3512 FM_BLEND_USN_ATTACK_TIME Default Summary A10 A20 A30 A40 0x3719 0x3719 0x3719 0x3719 14105 14105 14105 14105 0x2D00 0x2D00 A55 0x3719 Sets the thresholds for the RSSI metric for 14105 the stereo blend mitigation engine. 11520 11520 11520 11520 0x2D00 Set the limits for the stereo separation when driven by RSSI on the stereo blend 11520 mitigation engine. 0x0010 0x0010 0x0010 0x0010 0x0010 16 16 16 16 16 0x0FA0 0x0FA0 0xFA0 0xFA0 0xFA0 4000 4000 4000 4000 4000 0x2D00 0x2D00 0x1E3C 0x1E3C 0x1E3C 0x1E3C 7740 7740 7740 7740 0x2D00 0x2D00 Sets the stereo blend attack time in ms. Sets the stereo blend release time in ms. 0x0A14 Sets the thresholds for the multipath metric 2580 for the stereo blend mitigation engine. 11520 11520 11520 11520 0x2D00 Sets the limits for the stereo separation when driven by multipath on the stereo 11520 blend mitigation engine. 0x0010 0x0010 0x0010 0x0010 0x0010 16 16 16 16 16 0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0 4000 4000 4000 4000 4000 0x341B 0x341B 0x341B 0x341B 13339 13339 13339 13339 0x2D00 0x2D00 0x2D00 0x2D00 Sets the stereo blend attack time in ms. Sets the stereo blend release time in ms. 0x341B Set the thresholds for the USN metric for 13339 the stereo blend mitigation engine. 11520 11520 11520 11520 0x2D00 Sets the limits for the stereo separation when driven by USN on the stereo blend 11520 mitigation engine. 0x0010 0x0010 0x0010 0x0010 0x0010 16 16 16 16 16 0x2D00 0x2D00 Rev. 0.9 Sets the stereo blend attack time in ms. 49 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x3513 FM_BLEND_USN_RELEASE_TIME 0x3518 FM_BLEND_CHBW_LIMITS 0x3519 FM_BLEND_CHBW_STEREO_SEP 0x351A FM_BLEND_CHBW_ATTACK_TIME 0x351B FM_BLEND_CHBW 0x3600 FM_HICUT_RSSI_THRESHOLDS 0x3601 FM_HICUT_RSSI_CUTOFF_FREQ 0x3602 FM_HICUT_RSSI_ATTACK_TIME 0x3603 FM_HICUT_RSSI_RELEASE_TIME 0x3608 FM_HICUT_MULTIPATH_THRESHOLDS 0x3609 FM_HICUT_MULTIPATH_CUTOFF_FREQ 0x360A FM_HICUT_MULTIPATH_ATTACK_TIME 50 Default Summary A10 A20 A30 A40 A55 0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0 4000 4000 4000 4000 4000 0x0000 0X0000 0x0000 0x0000 0 0 0 0 Sets the stereo blend release time in ms. 0x0000 Set the limits for CHBW input metric on the stereo blend mitigation engine 0 0x2D2D 0x2D2D 0x2D2D 0x2D2D 0x2D2D Set the limits for the stereo separation when driven by CHBW on the stereo blend 11565 11565 11565 11565 11565 mitigation engine 0x0001 0x0001 0x0001 0x0001 0x0001 1 1 1 1 1 0x0001 0x0001 0x0001 0x0001 0x0001 1 1 1 1 1 0x230F 0x230F 0x230F 0x230F 8975 8975 8975 8975 0xB428 0xB428 0xB428 0xB428 46120 46120 46120 46120 0xB419 Sets the limits for the cutoff frequency when driven by RSSI on the L+R high cut mitiga46105 tion engine. 0x0010 0x0010 0x0010 0x0010 0x0064 16 16 16 16 100 0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0 4000 4000 4000 4000 4000 0x3250 0x3250 0x3250 0x3250 12880 12880 12880 12880 0xB428 0xB428 0xB428 0xB428 46120 46120 46120 46120 0x6419 Set the limits for the cutoff frequency when driven by multipath on the L+R high cut mit25625 igation engine. 0x0010 0x0010 0x0010 0x0010 0x0064 16 16 16 16 100 Rev. 0.9 Set stereo blend attack time in ms Set stereo blend release time in ms 0x230F Sets the thresholds for the RSSI metric for 8975 the L+R high cut mitigation engine. Sets the L+R high cut attack time in ms. Sets the L+R high cut release time in ms. 0x0A14 Sets the thresholds for the multipath metric 2580 for the L+R high cut mitigation engine. Sets the L+R high cut attack time in ms. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x360B FM_HICUT_MULTIPATH_RELEASE_TIME 0x3610 FM_HICUT_USN_THRESHOLDS 0x3611 FM_HICUT_USN_CUTOFF_FREQ 0x3612 FM_HICUT_USN_ATTACK_TIME 0x3613 FM_HICUT_USN_RELEASE_TIME 0x3618 FM_HICUTN_CHBW_LIMITS 0x3619 FM_HICUTN_CHBW_CUTOFF_FREQ 0x361A FM_HICUTN_CHBW_ATTACK_TIME 0x361B HM_HICUTN_CHBW_RELEASE_TIME 0x3700 FM_HIBLEND_RSSI_THRESHOLDS 0x3701 FM_HIBLEND_RSSI_CUTOFF_FREQ 0x3702 FM_HIBLEND_RSSI_ATTACK_TIME Default Summary A10 A20 A30 A40 A55 0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0 4000 4000 4000 4000 4000 0x250F 0x250F 0x250F 0x250F 9487 9487 9487 9487 0xB428 0xB428 0xB428 0xB428 46120 46120 46120 46120 0xB419 Sets the limits for the cutoff frequency when driven by USN on the L+R high cut mitiga46105 tion engine. 0x0010 0x0010 0x0010 0x0010 0x0064 16 16 16 16 100 0x0FA0 0x0FA0 0x0FA0 0x0FA0 0x0FA0 4000 4000 4000 4000 4000 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0xB4B4 0xB4B4 0xB4B4 0xB4B4 Sets the L+R high cut release time in ms. 0x250F Sets the thresholds for the USN metric for 9487 the L+R high cut mitigation engine. Sets the L+R high cut attack time in ms. Sets the L+R high cut release time in ms. 0x0000 Set the limits for the CHBW input metric on L+R high cut mitigation engine 0 0xB4B4 Set the limits for the cutoff frequency when driven by CHBW on the L+R high cut miti46260 gation engine 46260 46260 46260 46260 0x0001 0x0001 0x0001 0x0001 0x0001 1 1 1 1 1 0x0001 0x0001 0x0001 0x0001 0x0001 1 1 1 1 1 0x371B 0x371B 0x371B 0x371B 14107 14107 14107 14107 0xB41E 0xB41E Set L+R high cut attack time in ms Set L+R high cut release time in ms 0x371B Sets the thresholds for the RSSI metric for 14107 the L-R high cut mitigation engine. 46110 46110 46110 46110 0xB419 Sets the limits for the cutoff frequency when driven by RSSI on the L-R high-blend miti46105 gation engine. 0x0004 0x0004 0x0004 0x0004 0x0064 4 4 4 4 100 0xB41E 0xB41E Rev. 0.9 Sets the L-R high-blend attack time in ms. 51 AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x3703 FM_HIBLEND_RSSI_RELEASE_TIME 0x3708 FM_HIBLEND_MULTIPATH_THRESHOLDS 0x3709 FM_HIBLEND_MULTIPATH_CUTOFF_FREQ 0x370A FM_HIBLEND_MULTIPATH_ATTACK_TIME 0x370B FM_HIBLEND_MULTIPATH_RELEASE_TIME 0x3710 FM_HIBLEND_USN_THRESHOLDS 0x3711 FM_HIBLEND_USN_CUTOFF_FREQ 0x3712 FM_HIBLEND_USN_ATTACK_TIME 0x3713 FM_HIBLEND_USN_RELEASE_TIME 0x3718 FM_HIBLEND_CHBW_LIMITS Default A10 A20 A30 A40 A55 0x1F40 0x1F40 0x1F40 0x1F40 0x0FA0 8000 8000 8000 8000 4000 0x193C 0x193C 6460 6460 0xB41E 0xB41E 0x193C 0x193C 6460 6460 52 0x080F Sets the thresholds for the multipath metric 2063 for the L-R high-blend mitigation engine. 46110 46110 46110 46110 0x0004 0x0004 0x0004 0x0004 0x0064 4 4 4 4 100 0x1F40 0x1F40 0x1F40 0x1F40 0x0FA0 8000 8000 8000 8000 4000 0x371E 0x371E 0x371E 0x371E 14110 14110 14110 14110 0xB41E 0xB41E Sets the L-R high-blend attack time in ms. Sets the L-R high-blend release time in ms. 0x371E Sets the thresholds for the USN metric for 14110 the L-R high-blend mitigation engine. 46110 46110 46110 46110 0x9619 Sets the limits for the cutoff frequency when driven by USN on the L-R high-blend miti38425 gation engine. 0x0004 0x0004 0x0004 0x0004 0x0064 4 4 4 4 100 0x1F40 0x1F40 0x1F40 0x1F40 0x0FA0 8000 8000 8000 8000 4000 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0xB4B4 0xB4B4 46260 46260 0xB41E 0xB41E FM_HIBLEND_CHBW_CUTOFF_FREQ Sets the L-R high-blend release time in ms. 0x6419 Sets the limits for the cutoff frequency when driven by multipath on the L-R high-blend 25625 mitigation engine. 0xB41E 0xB41E 0x3719 Summary 0xB4B4 0xB4B4 46260 46260 Rev. 0.9 Sets the L-R high-blend attack time in ms. Sets the L-R high-blend release time in ms. 0x0000 Set the limits for the CHBW input metric on the hi-blend (L-R high cut) mitigation 0 engine. 0xB4B4 Set the limits for the cutoff frequency when driven by CHBW on the hi-blend (L-R high 46260 cut) mitigation engine. AN543 Table 12. FM Receiver Properties Summary (Continued) Address Name 0x371A FM_HIBLEND_CHBW_ATTACK_TIME 0x371B FM_HIBLEND_CHBW_RELEASE_TIME 0x4000 FM_RDS_INTERRUPT_SOURCE 0x4001 FM_RDS_INTERRUPT_FIFO_COUNT 0x4002 FM_RDS_CONFIG 0x4003 FM_RDS_CONFIDENCE Default Summary A10 A20 A30 A40 A55 0x0001 0x0001 0x0001 0x0001 0x0001 1 1 1 1 1 0x0001 0x0001 0x0001 0x0001 1 1 1 1 0x0000 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x1111 0x1111 0x1111 0x1111 0x1111 4369 4369 4369 4369 4369 Rev. 0.9 Set hi-blend (L-R high cut) attack time in ms 0x0001 Set hi-blend (L-R high cut) release time in ms. 1 Configures interrupt related to RDS. 0x0000 Sets the minimum number of RDS groups stored in the RDS FIFO before RDSRECV 0 is set. 0x0000 Configures RDS settings to enable RDS processing (RDSEN) and set RDS block 0 error thresholds. Sets the confidence level requirement for each RDS block. 53 AN543 7.2.1. FM Receiver Commands Command 0x30 FM_TUNE_FREQ The FM_TUNE_FREQ command sets the FM Receiver to tune to a frequency between 64 and 108 MHz in 10 kHz units. The CTS bit (and optional interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC interrupt is set when the command completes. This command may only be sent in powerup mode. The command clears the STC bit if it is already set. Command Bit 7 6 5 4 3 1 0 0x30 CMD ARG1 2 00 TUNEMODE[1:0] 0 ARG2 FREQH[7:0] ARG3 FREQL[7:0] ARG Bit Name 1 7:6 Reserved SMOOTHMETRICS INJSIDE[1:0] Function Always write 0. Sets the Desired Tuning Mode. 1 5:4 1 3 1 2 0 = Validated normal tune: Unconditionally stay on the new channel after tune, tune status is valid. 1 = Invalidated fast tune: Unconditionally stay on the new TUNEMODE[1:0] channel after tune, tune status invalid. 2 = Validated AF Tune: Jump back to previous channel if metric thresholds are not met (Si4755/57 only). 3 = Validated AF Check: Unconditionally jump back to the previous channel (Si4755/57 only). Reserved Always write 0. SMOOTHMETRICS Smoothly transition audio state after tune. 0 = Initialize audio state to match this new channel. 1 = Transition audio state from previous channel values to the new channel values. Note: This is the recommended setting when performing an AF check. Selects Injection Side. 1 54 1:0 INJSIDE[1:0] 0 = Automatic injection side selection by the tuner. 1 = Force low-side injection. 2 = Force high-side injection. Rev. 0.9 AN543 ARG Bit 2 7:0 3 7:0 Name Function FREQH[7:0] Tune Frequency High Byte. This byte in combination with FREQL selects the tune frequency in units of 10 kHz. In FM mode the valid range is from 6400 to 10800 (64-108 MHz). FREQL[7:0] Tune Frequency Low Byte. This byte in combination with FREQH selects the tune frequency in units of 10 kHz. In FM mode, the valid range is from 6400 to 10800 (64-108 MHz). Response Bit 7 6 STATUS CTS ERR 5 4 XX Rev. 0.9 3 2 1 0 RSQINT RDSINT ACFINT STCINT 55 AN543 Command 0x31 FM_SEEK_START The FM_SEEK_START command begins searching for a valid station. In order for a station to be considered valid, each of the following thresholds must be met: FM_VALID_SNR_THRESHOLD, FM_VALID_RSSI_THRESHOLD, FM_VALID_ASSI_THRESHOLD, FM_VALID_ISSI_THRESHOLD, and FM_VALID_MAX_TUNE_ERROR. Clears any pending STCINT, RSQINT, or RDSINT interrupt status. Seek can be cancelled through setting the CANCEL bit in the FM_RSQ_STATUS command. The CTS bit (and optional interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC interrupt is set when the command completes. This command may only be sent in powerup mode. The command clears the STCINT bit if it is already set. Command Bit 7 6 5 4 3 2 SEEKUP WRAP 1 0 0x31 CMD 0000 ARG1 00 ARG Bit Name Function 1 7:4 Reserved Always write 0000. 1 3 SEEKUP Seek Up/Down. Determines the direction of the search, either UP = 1, or DOWN = 0. 1 2 WRAP 1 1:0 Reserved Wrap/Halt. Determines whether the seek should Wrap = 1, or Halt = 0 when it hits the band limit. Always write 00. Response Bit 7 6 STATUS CTS ERR 56 5 4 XX Rev. 0.9 3 2 1 0 RSQINT RDSINT ACFINT STCINT AN543 Command 0x32 FM_RSQ_STATUS The FM_RSQ_STATUS command returns status information about the received signal quality. This command returns the Received Signal Strength Indicator (RSSI), Signal to Noise Ratio (SNR), Adjacent Channel Strength for 200 kHz (ASSI200), Adjacent Channel Strength for 100 kHz (LASSI and HASSI), frequency offset (FREQOFF), Multipath (MULT), Ultrasonic Noise (USN), Pilot Deviation (PILOTDEV), RDS Deviation (RDSDEV), Adjacent Channel Deviation for 200 kHz (ASSI200DEV), Deviation (DEV and STRONGDEV), and RDS PI code (RDSPI) associated with the desired channel. It also indicates valid channel (VALID) and AFC rail status (AFCRL). This command can be used to check if the received signal is above the RSSI high threshold as reported by RSSIHINT or below the RSSI low threshold as reported by RSSILINT. It can also be used to check if the signal is above the SNR high threshold as reported by SNRHINT or below the SNR low threshold as reported by SNRLINT. It can be used to check if the detected multipath is above the Multipath high threshold as reported by MULTHINT or below the Multipath low threshold as reported by MULTLINT. The command clears the RSQINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT, MULTHINT, and MULTLINT interrupt bits when the RSQACK bit of ARG1 is set. If the condition is still true after the interrupt is cleared, another interrupt will fire assuming that bit is enabled in FM_RSQ_INTERRUPT_SOURCE. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent when in powerup mode. FM_RSQ_ STATUS Command 7 6 5 4 3 2 1 0 RSQACK ATTUNE CANCEL STCACK 0x32 CMD 0000 ARG1 ARG Bit Name Function 1 7:4 Reserved Always write 0000. 1 3 RSQACK Clears RSQINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT, MULTHINT, and MULTLINT if set. 1 2 ATTUNE Returns the values of metrics as of tune time. When the ATTUNE bit is set, values returned for RSQ_STATUS are the values calculated at tune and do not change unless another FM_TUNE_FREQ or FM_SEEK_START command is called. This feature can be used to determine why seek stopped at the current station. 1 1 CANCEL Aborts a seek or tune currently in progress. 0 = Don't abort. 1 = Abort. 1 0 STCACK Clears the STC interrupt status indicator if set. Rev. 0.9 57 AN543 Response Bit 7 6 STATUS CTS ERR RESP1 RESP 2 MULTHINT MULTLINT BLTF X 5 4 XX ISSIHINT ISSILINT 3 2 1 0 RSQINT RDSINT ACFINT STCINT SNRHINT SNRLINT RSSIHINT RSSILINT SNRREADY RSSIREADY X RESP 3 READFREQ[15:8] RESP 4 READFREQ[7:0] RESP 5 FREQOFF[7:0] RESP 6 RSSI[7:0] RESP 7 SNR[7:0] RESP 8 ISSI[7:0] RESP 9 LASSI[7:0] RESP 10 HASSI[7:0] RESP 11 MULT[7:0] RESP 12 DEV[7:0] RESP 13 XXXXXXXX RESP 14 XXXXXXXX RESP 15 ASSI200[7:0] RESP 16 USN[7:0] RESP 17 PILOTDEV[7:0] RESP 18 RDSDEV[7:0] RESP 19 ASSI200DEV[7:0] RESP 20 STRONGDEV[7:0] RESP 21 RDSPI[15:8] RESP 22 RDSPI[7:0] 58 Rev. 0.9 INJSIDE AFCRL VALID AN543 RESP Bit Name 1 7 MULTHINT Function Multipath Detect High. 0 = Indicates that multipath value has not exceeded the Multipath high threshold set by FM_RSQ_MULTIPATH_HIGH_THRESHOLD. 1 = Indicates that multipath value has exceeded the Multipath high threshold set by FM_RSQ_MULTIPATH_HIGH_THRESHOLD. 1 6 MULTLINT Multipath Detect Low. 0 = Indicates that multipath value has not fallen below the Multipath low threshold set by FM_RSQ_MULTIPATH_LOW_THRESHOLD. 1 = Indicates that multipath value has fallen below the Multipath low threshold set by FM_RSQ_MULTIPATH_LOW_THRESHOLD. 1 5 ISSIHINT ISSI Detect High. (Available in Si475x-A30 only) 0 = Indicates that ISSI has not exceeded the ISSI high threshold set by FM_RSQ_ISSI_HIGH_THRESHOLD. 1 = Indicates that ISSI has exceeded the ISSI high threshold set by FM_RSQ_ISSI_HIGH_THRESHOLD. 1 4 ISSILINT ISSI Detect Low. (Available in Si475x-A30 only) 0 = Indicates that ISSI has not fallen below the ISSI low threshold set by FM_RSQ_ISSI_LOW_THRESHOLD. 1 = Indicates that ISSI has fallen below the ISSI low threshold set by FM_RSQ_ISSI_LOW_THRESHOLD. 1 3 SNRHINT SNR Detect High. 0 = Indicates that the received signal SNR has not exceeded the SNR high threshold set by FM_RSQ_SNR_HIGH_THRESHOLD 1 = Indicates that the received signal SNR has exceeded the SNR high threshold set by FM_RSQ_SNR_HIGH_THRESHOLD. 1 2 SNRLINT SNR Detect Low. 0 = Indicates that the received signal SNR has not fallen below the SNR low threshold set by FM_RSQ_SNR_LOW_THRESHOLD. 1 = Indicates that the received signal SNR has fallen below the SNR low threshold set by FM_RSQ_SNR_LOW_THRESHOLD. Rev. 0.9 59 AN543 RESP Bit Name 1 1 RSSIHINT Function RSSI Detect High. 0 = Indicates that the received signal RSSI has not exceeded the RSSI high threshold set by FM_RSQ_RSSI_HIGH_THRESHOLD. 1 = Indicates that the received signal RSSI has exceeded the RSSI high threshold set by FM_RSQ_RSSI_HIGH_THRESHOLD. 1 0 RSSILINT RSSI Detect Low. 0 = Indicates that the received signal RSSI has not fallen below the RSSI low threshold set by FM_RSQ_RSSI_LOW_THRESHOLD. 1 = Indicates that the received signal RSSI has fallen below the RSSI low threshold set by FM_RSQ_RSSI_LOW_THRESHOLD. 60 2 7 BLTF 2 6 Reserved 2 5 SNRREADY The SNRREADY and RSSIREADY bits indicate that the RSSI/SNR have been read as a result of a tune command. If either one of these bits are 0 this indicates that either the metric is being measured (because a tune is in progress) or that the metric was not measured during tune because the station was invalidated before the metric could be measured. In the case where a metric was not measured during tune, the tune time RSQ status will read back as 0 for the unmeasured metric. The normal running time status for these metrics is not affected and will report normally. 0 = SNR measurement in progress (tune in progress) or not taken (tune completed). 1 = SNR measurement ready. 2 4 RSSIREADY The SNRREADY and RSSIREADY bits indicate that the RSSI/SNR have been read as a result of a tune command. If either one of these bits are 0 this indicates that either the metric is being measured (because a tune is in progress) or that the metric was not measured during tune because the station was invalidated before the metric could be measured. In the case where a metric was not measured during tune, the tune time RSQ status will read back as 0 for the unmeasured metric. The normal running time status for these metrics is not affected and will report normally. 0 = RSSI measurement in progress (tune in progress) or not taken (tune completed). 1 = RSSI measurement ready. Band Limit. Reports if a seek hits the band limit (WRAP = 0 in FM_START_SEEK) or wrapped to the original frequency (WRAP = 1). Values may vary. Rev. 0.9 AN543 RESP Bit Name Function 2 3 Reserved Values may vary. 2 2 INJSIDE Injection side used. 0 = Low-side injection is being used 1 = High-side injection is being used 2 1 AFCRL Set if the AFC rails. AFC gets railed if FREQOFF > FM_VALID_MAX_TUNE_ERROR. 2 0 VALID (Si475x-A20 and earlier) Reports if the channel is valid based on the settings of: FM_VALID_RSSI_THRESHOLD, FM_VALID_SNR_THRESHOLD, FM_VALID_MAX_TUNE_ERROR (Si475x-A30 and later) Reports if the channel is valid based on the settings of: FM_VALID_RSSI_THRESHOLD, FM_VALID_SNR_THRESHOLD, FM_VALID_MAX_TUNE_ERROR, FM_VALID_ASSI_THRESHOLD, FM_VALID_ISSI_THRESHOLD 3,4 15:0 READFREQ[15:0] Returns the currently tuned frequency. 5 7:0 FREQOFF[7:0] 6 7:0 RSSI[7:0] Received Signal Strength indicator in dBV (-128 to 127) 7 7:0 SNR[7:0] RF SNR indicator in dB (-128 to 127). 8 7:0 ISSI[7:0] Image Signal Strength Indicator reports the image power relative to carrier (-128 to 127). This metric is only valid when ATTUNE = 1. Only applicable to Si475x-A30 and later. 9 7:0 LASSI[7:0] Low side Adjacent (100 kHz) Channel Strength Indicator reports the (Signal + Noise) power relative to the carrier.(-128 to 127) 10 7:0 HASSI[7:0] High side Adjacent (100 kHz) Channel Strength Indicator reports the (Signal + Noise) power relative to the carrier.(-128 to 127) 11 7:0 MULT[7:0] Multipath Indicator. (For Si475x-A20 and later) Range: 0-100% (ForSi475x-A10) Multipath = MULT/127 x 100% Range: 0-127 12 7:0 DEV[7:0] Frequency Deviation metric in kHz. 13, 14 15:0 Reserved Values may vary. Signed frequency offset in units set by FM_VALID_FREQOFF_SCALE (-128 to 126) Rev. 0.9 61 AN543 RESP Bit Name Function 15 7:0 ASSI200[7:0] Adjacent Channel (200 kHz) Strength Indicator reports the (Signal + Noise) power relative to the carrier. This metric reports the sum of high and low adjacent channel strengths. (-128 to 127) 16 7:0 USN[7:0] 17 7:0 PILOTDEV[7:0] Ultrasonic Noise Indicator in -dBFS (0 to 127). 127 corresponds to 127 dB down from full scale. (Only applicable to Si475x-A30 and later) Pilot deviation in units of 100 Hz. Range:0-127 18 7:0 RDSDEV[7:0] 19 7:0 (Only applicable to Si475x-A30 and later) Adjacent ASSI200DEV[7:0] Channel (200 kHz) Deviation. Deviation is equal to ASSI200DEV x 1.5 kHz minus 12 kHz. 20 7:0 (Only applicable to Si475x-A30 and later) Deviation of very strong desired signals. This is an alternative to DEV, which can become erroneous in the presence of very strong signals. STRONGDEV is the weighted sum of FM STRONGDEV[7:0] mono/stereo (L + R) and stereo (L - R) deviation. Approximately, deviation in kHz = STRONGDEV x f(mod), where f(mod) is 5.55 kHz for mono signals, or 2.75 kHz for stereo signals. 21,22 15:0 RDSPI[15:0] (Only applicable to Si475x-A30 and later) RDS deviation in units of 100 Hz. (Only applicable to Si475x-A30 and later) RDS PI code. Command 0x35 FM_ACF_STATUS The FM_ACF_STATUS command returns status information about automatically-controlled features. This command returns the Soft Mute Attenuation, Channel Filter Bandwidth, HICUT cutoff frequency, HIBLEND cutoff frequency, and Stereo Separation associated with the desired channel. Stereo Separation will only be non-zero if the pilot indicator is set. If SMUTE bit is high, it indicates that audio is soft-muted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Command Bit 7 6 5 CMD 3 2 1 0 0x35 ARG1 62 4 0000000 ACFACK ARG Bit Name Function 1 7:1 Reserved Always write 0000000. 1 0 ACFACK If set clears ACFINT and any ACF interrupts bits. Rev. 0.9 AN543 Response Bit 7 6 STATUS CTS ERR RESP1 5 XX CHBWH_ INT XX 4 BLEND_ INT 3 2 1 0 RSQINT RDSINT ACFINT STCINT HIBLEND_ INT HICUT_ INT CHBW_ SOFTMUTE_ INT INT XXXXXXX RESP2 XXX RESP3 SMATTN[4:0] RESP4 CHBW[7:0] RESP5 HICUT[7:0] RESP6 HIBLEND[7:0] RESP7 RESP8 PILOT SMUTE STBLEND[6:0] LOWCUT[7:0] Rev. 0.9 63 AN543 RESP Bit Name 1 7:6 Reserved 1 5 CHBWH_INT (Available on Si475x-A40 only.) If set, indicates that the channel filter bandwidth is greater than the threshold set by FM_ACF_CHBW_THRESHOLD. 1 4 BLEND_INT If set, indicates that stereo separation has crossed below the blend threshold set by FM_ACF_BLEND_THRESHOLD. 1 3 HIBLEND_INT If set, indicates that the HIBLEND cutoff frequency is lower than the threshold as set by FM_ACF_HIBLEND_THRESHOLD. 1 2 HICUT_INT If set, indicates that the HICUT cutoff frequency is lower than the threshold set by FM_ACF_HICUT_THRESHOLD. 1 1 CHBW_INT If set, indicates that the Channel Filter Bandwidth is less than the threshold set by FM_ACF_CHBW_THRESHOLD. 1 0 SOFTMUTE_INT If set, indicates that softmute attenuation has increased above the softmute threshold as set by ACF_SM_THRESHOLD. 2 7:1 Reserved 2 0 SMUTE 3 7:5 Reserved 3 4:0 SMATTN[7:0] 4 7:0 CHBW[7:0] Channel filter bandwidth in kHz. Range: 0-150. 5 7:0 HICUT[7:0] LPR cutoff frequency in units of 100 Hz. Range: 10-180. 6 7:0 HIBLEND[7:0] LMR cutoff frequency in units of 100 Hz. Range: 10-180. 7 7 PILOT 7 6:0 STBLEND[6:0] Indicates stereo separation. STBLEND will only be non-zero if PILOT = 1. Range 0-100. LOWCUT[7:0] (Available in Si475x-A30 and later.) Lowcut cutoff frequency in units of 10 Hz. Only available if lowcut is enabled by the FM_LOWCUT_MIN_FREQ property. Range 1-100. 8 64 7:0 Function Values may vary. Values may vary. 0 = Audio is not soft muted. 1 = Audio is soft muted. Values may vary. Soft mute attenuation level in dB. Range: 0-31. 0 = Stereo pilot is not present. 1 = Stereo pilot is present. Rev. 0.9 AN543 Command 0x36 FM_RDS_STATUS (Si4751/53/55/57 Only) The FM_RDS_STATUS command returns RDS information for current channel and reads an entry from the RDS FIFO. RDS information includes synch status, FIFO status, group data (blocks A, B, C, and D), and block errors corrected. Maximum RDS FIFO size is 25 groups. This command clears the RDSINT interrupt bit when INTACK bit in ARG1 is set, and, if MTFIFO is set, the entire RDS receive FIFO is cleared (FIFO is always cleared during FM_TUNE_FREQ or FM_SEEK_START). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Command Bit 7 6 5 4 3 1 0 STATUS_ONLY MTFIFO INTACK 0x36 CMD 00000 ARG1 ARG Bit Name 1 7:3 Reserved 1 2 2 STATUS_ONLY Function Always write 00000. Status Only. Determines if data should be removed from the RDS FIFO. 0 = Data is removed from RDS FIFO, and RDSFIFOUSED decrements by one. Data in BLOCKA, BLOCKB, BLOCKC, BLOCKD, and BLE contain the oldest data in the RDS FIFO. 1 = Data is not removed from RDSFIFO, and the RDSFIFOUSED value stays the same. Data in BLOCKA, BLOCKB, BLOCKC, BLOCKD, BLE, PI, TP, PTY, and status contain the last valid data received for the current station. 1 1 MTFIFO Empty FIFO. The FIFO will always be cleared during FM_TUNE_FREQ and FM_SEEK_START. 0 = If FIFO not empty, read and remove oldest FIFO entry. 1 = Clear RDS Receive FIFO. 1 0 INTACK Interrupt Acknowledge. 0 = RDSINT status preserved. 1 = Clears RDSINT. Rev. 0.9 65 AN543 Response Bit 7 6 STATUS CTS ERR RESP1 XXX RESP2 XXX RESP3 XX 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT X RDSSYNCINT RDSFIFOINT X RDSSYNC RDSFIFOLOST RDSTPPTYINT RDSPIINT TPPTYVALID PIVALID TP PTY[4:0] RESP4 PI[15:8] RESP5 PI[7:0] RESP6 RDSFIFOUSED[7:0] RESP7 BLEA[1:0] BLEB[1:0] BLEC[1:0] RESP8 BLOCKA[15:8] RESP9 BLOCKA[7:0] RESP10 BLOCKB[15:8] RESP11 BLOCKB[7:0] RESP12 BLOCKC[15:8] RESP13 BLOCKC[7:0] RESP14 BLOCKD[15:8] RESP15 BLOCKD[7:0] RESP16 IQSNR[7:0] 66 Rev. 0.9 BLED[1:0] AN543 RESP Bit Name 1 7:5 Reserved 1 4 RDSTPPTYINT 1 3 RDSPIINT 1 = PI (Program Identification) code has changed. 1 2 Reserved Values may vary. 1 1 RDSSYNCINT 1 = RDS synchronization has changed. 1 0 RDSFIFOINT 1 = RDS was received and the RDS FIFO is full or has atleast FM_RDS_INTERRUPT_FIFO_COUNT entries. 2 7:5 Reserved 2 4 TPPTYVALID 2 3 PIVALID 1 = Indicates that PI code is valid. 2 2 Reserved Values may vary. 2 1 RDSSYNC 2 0 RDSFIFOLOST 3 7:6 Reserved 3 5 TP 3 4:0 PTY[4:0] Current channel's PTY code if TPPTYVALID is 1. 4,5 15:0 PI[15:0] Current channel's PI code if PIVALID is set to 1. 6 7 7 7 7:0 7:6 5:4 3:2 RDSFIFOUSED[7:0] Function Values may vary. 1 = TP (Traffic Program) flag and/or PTY (Program Type) code has changed. Values may vary. 1 = Indicates that TP flag and PTY code are valid. 1 = RDS is currently synchronized. 1 = Indicates that one or more RDS groups have been discarded due to FIFO overrun since last call to FM_RDS_STATUS. Values may vary. Current channel's TP flag if TPPTYVALID is set to 1. RDS FIFO Used. Number of groups remaining in the RDS FIFO (0 if empty). If non-zero, BLOCKA-BLOCKD contain the oldest FIFO entry and RDSFIFOUSED decrements by one on the next call to RDS_FIFO_STATUS (assuming no RDS data received in the interim). BLEA[1:0] RDS Block A Corrected Errors. 0 = No errors. 1 = 1-2 bit errors detected and corrected. 2 = 3-5 bit errors detected and corrected. 3 = Uncorrectable. BLEB[1:0] RDS Block B Corrected Errors. 0 = No errors. 1 = 1-2 bit errors detected and corrected. 2 = 3-5 bit errors detected and corrected. 3 = Uncorrectable. BLEC[1:0] RDS Block C Corrected Errors. 0 = No errors. 1 = 1-2 bit errors detected and corrected. 2 = 3-5 bit errors detected and corrected. 3 = Uncorrectable. Rev. 0.9 67 AN543 RESP 68 Bit Name Function RDS Block D Corrected Errors. 0 = No errors. 1 = 1-2 bit errors detected and corrected. 2 = 3-5 bit errors detected and corrected. 3 = Uncorrectable. 7 1:0 BLED[1:0] 8,9 15:0 BLOCKA[15:0] Block A group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block A data if STATUSONLY is 1. 10,11 15:0 BLOCKB[15:0] Block B group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block B data if STATUSONLY is 1. 12,13 15:0 BLOCKC[15:0] Block C group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block C data if STATUSONLY is 1. 14,15 15:0 BLOCKD[15:0] Block D group data from oldest FIFO entry if STATUSONLY is 0. Last valid Block D data if STATUSONLY is 1. 16 7:0 IQSNR[7:0] (Available in Si475x-A40 and later.) RDS I/Q SNR. Range: -128 to 127 Rev. 0.9 AN543 Command 0x37 FM_RDS_BLOCKCOUNT (Si4751/53/55/57 Only) The FM_RDS_BLOCKCOUNT command returns RDS expected, received, and uncorrectable block statistic information. Reset info by setting CLEAR bit or sending FM_TUNE_FREQ or FM_SEEK_START commands. Once EXPECTED saturates at 65535, all other block count statistics will be frozen until the counts are cleared. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent when in powerup mode. Command Bit 7 6 5 4 3 2 1 0 0x37 CMD 0000000 ARG1 ARG Bit Name 1 7:1 Reserved 1 0 CLEAR CLEAR Function Always write 0000000. Clears the block counts if set. The current block counts will be reported before they are cleared. Response Bit 7 6 STATUS CTS ERR 5 4 XX 3 2 1 0 RSQINT RDSINT ACFINT STCINT RESP1 XXXXXXXX RESP 2 EXPECTED[15:8] RESP 3 EXPECTED[7:0] RESP 4 RECEIVED[15:8] RESP 5 RECEIVED[7:0] RESP 6 UNCORRECTABLE[15:8] RESP 7 UNCORRECTABLE[7:0] Rev. 0.9 69 AN543 RESP Bit Name 1 7:0 Reserved 2,3 15:0 EXPECTED[15:0] Number of expected RDS blocks. RECEIVED[15:0] Number of received RDS blocks. Under ideal conditions, EXPECTED and RECEIVED would be identical. The difference between these two numbers is the number of blocks lost. UNCORRECTABLE[15:0] Number of uncorrectable RDS blocks. These blocks have been received, but were found to have uncorrectable errors. The block error rate (BLER) is calculated by: BLER = (UNCORRECTABLE + (EXPECTED-RECEIVED)) / EXPECTED 4,5 6,7 70 15:0 15:0 Function Values may vary. Rev. 0.9 AN543 7.2.2. FM Receiver Properties Property 0x0302 AUDIO_DE_EMPHASIS The AUDIO_DE_EMPHASIS property sets the FM Receive deemphasis to 50 or 75 s. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 75 s. Default: 0 AUDIO_DE_EMPHASIS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0x0000 DE_EMPH 0x0000 0 Bit Name Function 15:1 Reserved Always write 0. 0 DE_EMPH Sets the FM Receive de-emphasis to 50 or 75 s. Default is 75 s. 0 = 75 sec 1 = 50 sec Property 0x0400 FM_SOFT_MUTE_MAX_ATTENUATION The FM_SOFT_MUTE_MAX_ATTENUATION property sets the maximum attenuation in dB that will be applied by the softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 8 Units: dB FM_SOFT_MUTE_MAX_ATTENUATION 15 14 13 12 11 9 8 7 6 5 4 3 2 0x000 SMATTN[6:0] 0x000 0x08 Bit Name 15:7 Reserved 6:0 10 SMATTN[6:0] 1 0 Function Always write 0. Sets the maximum attenuation in dB that will be applied by the softmute feature. Default is 8 dB. (Si475x-A20 and earlier) Range is 0-31. (Si475x-A30 and later) Range is 0-63 dB. Rev. 0.9 71 AN543 Property 0x0401 FM_SOFT_MUTE_TRIGGER_THRESHOLD The FM_SOFT_MUTE_TRIGGER_THRESHOLD property sets the RSSI/SNR threshold in dB to engage softmute. If USE_RSSI is set in FM_ACF_CONTROL_SOURCE property, then property 0x0401 refers to RSSI threshold. If USE_RSSI is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 8 Si475x/5xC-A55, Default: 2 Units: dB FM_SOFT_MUTE_TRIGGER_THRESHOLD 15 14 Bit 72 13 12 11 10 9 8 7 6 5 4 3 2 SNR_SMTRGTH[7:0] RSSI_SMTRGTH[7:0] 0x00 0x02 Name 1 0 Function 15:8 Sets the SNR threshold in dB to engage softmute, default is 0. SNR_SMTRGTH[7:0] Range is -127 ~ 127. This field is only available in Si475x/5xC-A55. 7:0 Sets the RSSI threshold in dB to engage softmute. Si475x/5xC-A55, Default is 2 dB RSSI_SMTRGTH[7:0] Range is 0 to 15 dB for Si475x-A10 and -127 to 127 dB for Si475x-A20 or later. Rev. 0.9 AN543 Property 0x0402 FM_SOFT_MUTE_END_THRESHOLD The FM_SOFT_MUTE_END_THRESHOLD property sets the SNR threshold in dB at which softmute attenuation will be set to its maximum value. When the SNR is at this level or lower, the audio attenuation will be set to FM_SOFT_MUTE_MAX_ATTENUATION. If USE_RSSI is set in the FM_ACF_CONTROL_SOURCE property, then property 0x0402 refers to the RSSI threshold. If USE_RSSI is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0 Si475x/5xC-A55, Default: -6 Units:dB FM_SOFT_MUTE_END_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SNR_SMENDTH[7:0] RSSI_SMENDTH[7:0] 0x00 0xFA Bit Name 1 0 Function 15:8 Sets SNR threshold in dB to end the softmute, default is 0. SNR_SMENDTH[7:0] Range is -127 ~ 127 This field is only available in Si475x/5xC-A55. 7:0 Sets the RSSI threshold in dBuV to end the softmute. Si475x/5xC-A55, Default is -6 dB. Si475x-A40 and earlier, default is 0. RSSI_SMENDTH[7:0] Range is 0 to 15 dB for Si475x-A10, and -127 to127 dB for Si475x-A20 or later. Property 0x0403 FM_SOFT_MUTE_RELEASE_TIME The FM_SOFT_MUTE_RELEASE_TIME property sets the maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 500 Units: ms FM_SOFT_MUTE_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x01F4 Rev. 0.9 73 AN543 Bit 15:0 Name Function RELEASE[15:0] Sets the maximum time in ms it takes to unmute the audio. Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage. Default is 500 ms. Range is 1-32767 ms. Property 0x0404 FM_SOFT_MUTE_ATTACK_TIME The FM_SOFT_MUTE_ATTACK_TIME property sets the maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier, Si475x-A40 and later: This property is not available Units: ms FM_SOFT_MUTE_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0078 Bit 15:0 Name Function ATTACK[15:0] Sets the maximum time in ms it takes to mute the audio. Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/ disengage. Default is 120 ms. Range is 1-32767 ms. Property 0x0405 FM_SOFT_MUTE_MAX_ATTENUATION_AGC (Si4754/55/56/57 Only) When AGC is engaged, the FM_SOFT_MUTE_MAX_ATTENUATION_AGC property sets the maximum attenuation in dB that will be applied by the RSSI/SNR softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x0080 FM_SOFT_MUTE_MAX_ATTENUATION_AGC 15 74 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 IGNORE_AGC SMATTN[6:0] 0x00 1 0x00 Rev. 0.9 1 0 AN543 Bit Name 15:8 Reserved Function Always write to 0. 7 IGNORE_AGC 6:0 SMATTN[6:0] Selects which set of properties control softmute when AGC is engaged. 0 = Use properties 0x0405-0x0409 when the AGC is engaged, and properties 0x0400-0x0404 otherwise. 1 = Always use only properties 0x0400-0x0404. When AGC is engaged, sets the maximum attenuation in dB that will be applied by the RSSI/SNR softmute feature. Default is 0 dB. Range is 0- 63 dB. Property 0x0406 FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC (Si4754/55/56/57 Only) When AGC is engaged, the FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC property sets the RSSI/SNR threshold in dB to engage softmute. If USE_RSSI bit is set in FM_ACF_CONTROL_SOURCE property (0x1306), then this property refers to RSSI threshold. If USE_RSSI bit is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 8 Units: dB FM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SMTRGTH_AGC[7:0] 0x00 0x08 Bit Name 15:8 Reserved 7:0 SMTRGTH_AGC[7:0] 1 0 Function Always write to 0. When AGC is engaged, sets the RSSI/SNR threshold in dB to engage softmute. Default is 8 dB. Range is -127 to 127 dB. Rev. 0.9 75 AN543 Property 0x0407 FM_SOFT_MUTE_END_THRESHOLD_AGC (Si4754/55/56/57 Only) When AGC is engaged, the FM_SOFT_MUTE_END_THRESHOLD_AGC property sets the RSSI/SNR threshold in dB at which softmute attenuation will be set to its maximum value. When the RSSI/SNR is at this level or lower, the audio attenuation will be set to FM_SOFT_MUTE_MAX_ATTENUATION_AGC. If USE_RSSI bit is set in FM_ACF_CONTROL_SOURCE property (0x1306), then this property refers to RSSI threshold. If USE_RSSI bit is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0 Units: dB FM_SOFT_MUTE_END_THRESHOLD_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SMTRGTH_AGC[7:0] 0x00 0x08 Bit Name 15:8 Reserved 7:0 SMTRGTH_AGC[7:0] 1 0 Function Always write to 0. When AGC is engaged, sets the RSSI/SNR threshold in dB to engage softmute. Default is 8 dB. Range is -127 to 127 dB. Property 0x0408 FM_SOFT_MUTE_RELEASE_TIME_AGC (Si4754/55/56/57 Only) When AGC is engaged, the FM_SOFT_MUTE_RELEASE_TIME_AGC property sets maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 500 Units: ms FM_SOFT_MUTE_RELEASE_TIME_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE_AGC[15:0] 0x01F4 Bit 15:0 76 Name Function Sets the maximum time in ms it takes to unmute the audio. Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can RELEASE_AGC[15:0] engage/disengage. Default is 500 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x0409 FM_SOFT_MUTE_ATTACK_TIME_AGC (Si4754/55/56/57 Only) When AGC is engaged, the FM_SOFT_MUTE_ATTACK_TIME_AGC property sets maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier, Si475x-A40 and later: This property is not available Si475x-A30, Default: 120 Units: ms FM_SOFT_MUTE_ATTACK_TIME_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK_AGC[15:0] 0x0078 Bit Name Function 15:0 ATTACK_AGC[15:0] Sets the maximum time in ms it takes to unmute the audio. Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage.Default is 120 ms. Range is 1-32767 ms. Property 0x040A FM_SOFT_MUTE_USN_LIMITS The FM_SOFT_MUTE_USN_LIMITS property sets the values of USN for which audio is minimally and maximally muted by USN-based soft mute. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: USN will generally be negative under signal conditions where soft mute is desirable. The recommended setting is 0xCEE2 (YMIN = -50, YMAX = -30). Si475x-A20 and earlier, Si475x-A40 and later: This property is not available Si475x-A30, Default: 0x060E Units: ms FM_SOFT_MUTE_USN_LIMITS 15 14 13 12 11 10 9 8 7 6 5 4 3 YMIN[7:0] YMAX[7:0] 0x06 0x0E 2 1 0 Bit Name Function 15:8 YMIN[7:0] Sets the value of USN that causes minimum attenuation for USNbased soft mute. Default is 6. Range is -127 to 127. 7:0 YMAX[7:0] Sets the value of USN that causes maximum attenuation for USN-based soft mute. Default is 14. Range is -127 to 127. Rev. 0.9 77 AN543 Property 0x040B FM_SOFT_MUTE_USN_ATTENUATION The FM_SOFT_MUTE_USN_ATTENUATION property sets the limits for soft mute attenuation when driven by USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier, Si475x-A40 and later: This property is not available. Si475x-A30, Default: 0x0000 Units: dB FM_SOFT_MUTE_USN_ATTENUATION 15 14 13 12 11 10 9 8 7 6 5 4 3 YMIN[7:0] YMAX[7:0] 0x00 0x00 2 1 0 Bit Name Function 15:8 YMIN[7:0] Sets the minimum attenuation in dB for USN-based soft mute. Default is 0. Range is 0-63. 7:0 YMAX[7:0] Sets the maximum attenuation in dB for USN-based soft mute. Default is 0. Range is 0-63. Property 0x040C FM_SOFT_MUTE_USN_ATTACK_TIME The FM_SOFT_MUTE_USN_ATTACK_TIME property sets maximum time in ms it takes to mute the audio based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier, Si475x-A40 and later: This property is not available. Si475x-A30, Default: 0x0080 Units: ms FM_SOFT_MUTE_USN_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0080 78 Bit Name Function 15:0 ATTACK[15:0] Sets the USN-based soft mute attack time in ms. Note that there will be 16 ms of filter delay for USN metric before softmute can engage/disengage. Default is 128. Range is 1-32767. Rev. 0.9 AN543 Property 0x040D FM_SOFT_MUTE_USN_RELEASE_TIME The FM_SOFT_MUTE_USN_RELEASE_TIME property sets maximum time in ms it takes to unmute the audio based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier, Si475x-A40 and later: This property is not available Si475x-A30, Default: 0x0100 Units: ms FM_SOFT_MUTE_USN_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0004 Bit 15:0 Name Function RELEASE[15:0] Sets the USN-based soft mute release time in ms. Note that there will be 16 ms of filter delay for USN metric before softmute can engage/disengage. Default is 256. Range is 1-32767. Property 0x040E FM_SOFT_MUTE_ASSI200DEV_LIMITS The FM_SOFT_MUTE_ASSI200DEV_LIMITS property sets the ASSI200DEV threshold to engage softmute and sets the ASSI200DEV threshold at which softmute attenuation will be set to its maximum value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 and earlier: Range: 4-248 ms. Si475x-A20 and later: Range is 4-4096 ms. FM_SOFT_MUTE_ASSI200DEV_LIMITS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 SMTRGTH_ASSI200DEV[7:0] SMENDTH_ASSI200DEV[7:0] 0x33 0x5A 1 0 Bit Name Function 15:8 SMTRGTH_ASSI200DEV[7:0] Sets the ASSI200DEV threshold to engage softmute. Default is 51. Range is 0 to 150. 7:0 SMENDTH_ASSI200DEV[7:0] Sets the ASSI200DEV threshold at which softmute attenuation will be set to its maximum value. Default is 90. Range is 0 to 150. Rev. 0.9 79 AN543 Property 0x040F FM_SOFT_MUTE_ASSI200DEV_ATTENUATION The FM_SOFT_MUTE_ASSI200DEV_ATTENUATION property sets the maximum attenuation in dB that will be applied by the ASSI200DEV softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0 Units: dB FM_SOFT_MUTE_ASSI200DEV_ATTENUATION 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SMATTN_ASSI200DEV[6:0] 0x00 0x00 Bit Name 15:8 Reserved 7:0 SMATTN_ASSI200DEV[6:0] 1 0 Function Always write to 0. Sets the maximum attenuation in dB that will be applied by the ASSI200DEV softmute feature. Default is 0 dB. Range is 0- 63 dB. Property 0x0410 FM_SOFT_MUTE_ASSI200DEV_ATTACK_TIME The FM_SOFT_MUTE_ASSI200DEV_ATTACK_TIME property sets maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 128 Units: ms FM_SOFT_MUTE_ASSI200DEV_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK_ASSI200DEV[15:0] 0x0080 Bit 15:0 80 Name ATTACK_ASSI200DEV[15:0] Function Sets the maximum time in ms it takes to mute the audio. Note that there will be 16 ms of filter delay for the ASSI200DEV metric before softmute can engage/disengage. Default is 128 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x0411 FM_SOFT_MUTE_ASSI200DEV_RELEASE_TIME The FM_SOFT_MUTE_ASSI200DEV_RELEASE_TIME property sets maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 256 Units: ms FM_SOFT_MUTE_ASSI200DEV_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE_ASSI200DEV[15:0] 0x0100 Bit Name Function Sets the maximum time in ms it takes to unmute the audio. Note that there will be 16 ms of filter delay for the ASSI200DEV RELEASE_ASSI200DEV[15:0] metric before softmute can engage/disengage. Default is 256 ms. Range is 1-32767 ms. 15:0 Property 0x0700 FM_AGC_FE_CONFIG The FM_AGC_FE_CONFIG property specifies the input path for the RF signal and other FE configuration options. This property should only be set before the first tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Changes to this property take effect after the next tune is completed. Default: 0x0080 FM_AGC_FE_CONFIG 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0x00 FMLNAZ 1000 INPUTSELECT[3:0] 0x00 0 1000 0x0 Bit Name 15:9 Reserved Always write 0. 8 FMLNAZ 0 = LNA input impedance is 50 .(Normal Operation) 1 = LNA input impedance is 100 (Loop-through mode: two receivers splitting a single antenna signal) (Si4754/55/56/57 only) 7:4 Reserved Always write 1000. 3:0 INPUTSELECT[3:0] Function 0 = Received signal comes into FMI pin, out FMO and then the mixer pin. 1 = Received signal comes directly into the mixer at the FMXIP/ FMIN pins. Rev. 0.9 81 AN543 Property 0x0701 FM_AGC_PD_CONFIG The FM_AGC_PD_CONFIG property specifies behavior of the FM peak detectors and attenuators. This property should only be set before the first tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Changes to this property take effect after the next tune is completed. Default: 0x0270 FM_AGC_PD_CONFIG 15 14 12 11 10 9 8 7 6 5 4 3 2 1 0 0x0 LNA_MODE 00100 MIXER_PD[2:0] 0x00 LNA_PD[1:0] 0x0 0 00100 0x7 0x00 0x00 Bit Name 15:13 Reserved 12 LNA_MODE 11:7 Reserved 6:4 MIXER_PD[2:0] 3:2 Reserved 1:0 82 13 LNA_PD[1:0] Function Always write 0. LNA_MODE default: 0 This property only used when the LNA gain and one or both of the attenuators are controlled by the same peak detector. 0 = Reduce LNA gain and then attenuate with FMAGC1/2. 1 = Attenuate with FMAGC1/2 and then reduce LNA gain. Always write 00100. MIXER_PD[2:0] default: 0x7. 0 = Peak detector not used. 1 = Controls FMAGC1. 2 = Controls FMAGC2. 3 = Controls FMAGC1 and FMAGC2. 4 = Controls LNA gain. 5 = Controls LNA gain and FMAGC1. 6 = Controls LNA gain and FMAGC2. 7 = Controls LNA gain, FMAGC1 and FMAGC2. Always write 0. LNA_PD[1:0] default: 0x0 0 = Peak detector not used 1 = Controls FMAGC1 2 = Controls FMAGC2 3 = Controls FMAGC1 and FMAGC2 Rev. 0.9 AN543 Property 0x0702 FM_LNA_AGC_ATTACK_MS The FM_LNA_AGC_ATTACK_MS property sets the number of milliseconds the wide-band RF high-peak detector must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3 to 5 ms. If the peak detector trips, the internal counter is incremented by 4 ms.The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4 Units: ms FM_LNA_AGC_ATTACK_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RF_AGC_ATTACK_MS[15:0] 0x0004 Bit 15:0 Name Function RF_AGC_ATTACK_MS[15:0] Number of milliseconds the wideband RF highpeak detector must be exceeded before attenuating the appropriate block. Default is 4 ms. Si475x-A10 and earlier: Range: 4-248 ms. Si475x-A20 and later: Range is 4-4096 ms. Rev. 0.9 83 AN543 Property 0x0703 FM_LNA_AGC_RELEASE_MS The FM_LNA_AGC_RELEASE_MS property sets the number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled once every 3 to 5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 80 Units: ms FM_LNA_AGC_RELEASE_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RF_AGC_RELEASE_MS[15:0] 0x0050 Bit 15:0 84 Name Function Number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. RF_AGC_RELEASE_MS[15:0] Default is 80 ms Si475x-A10 and earlier: Range: 4-248 ms. Si475x-A20 and later: Range is 4-4096 ms. Rev. 0.9 AN543 Property 0x0704 FM_LNA_AGC_PD_THRESHOLD The FM_LNA_AGC_PD_THRESHOLD property sets the high threshold and hysteresis for the LNA peak detector. The high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB below the high threshold the level must drop before the AGC decreases attenuation. It is possible to decrease the likelihood of intermod break-in by decreasing the peak detector threshold from the default and it is possible to decrease the likelihood of desensitization by increasing the peak detector threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x4F05 FM_LNA_AGC_PD_THRESHOLD 15 14 Bit 15:8 7:0 13 12 11 10 9 8 7 6 5 4 3 HIGH[7:0] HYST[7:0] 0x4F 0x05 Name 2 1 0 Function HIGH[7:0] Sets the level in dBV at which AGC increases attenuation HIGH[7:0] Range: 73-87 73 = 73 dBV 75 = 75 dBV 77 = 77 dBV 79 = 79 dBV 81 = 81 dBV 83 = 83 dBV 85 = 85 dBV 87 = 87 dBV HYST[7:0] Sets how many dB below the high threshold the level must drop before the AGC decreases attenuation. HYST[7:0] Range: 3-6 3 = 3 dB 4 = 4 dB 5 = 5 dB 6 = 6 dB Rev. 0.9 85 AN543 Property 0x0705 FM_MIXER_AGC_ATTACK_MS The FM_MIXER_AGC_ATTACK_MS property sets the number of milliseconds the wideband mixer high-peak detector must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3-5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 4 Si475x/5xC-A55, Default: 248 Units: ms FM_MIXER_AGC_ATTACK_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MIX_AGC_ATTACK_MS[15:0] 0x00F8 Bit 15:0 86 Name Function MIX_AGC_ATTACK_MS[15:0] Number of milliseconds the wideband RF highpeak detector must be exceeded before attenuating the appropriate block. Si475x/5xC-A55, Default is 248 ms Si475x-A10 and earlier: Range: 4-248 ms Si475x-A20 and later: Range is 4-4096 ms Rev. 0.9 AN543 Property 0x0706 FM_MIXER_AGC_RELEASE_MS The FM_MIXER_AGC_RELEASE_MS property sets the number of milliseconds the wideband mixer low-peak detector must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled once every 3-5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 80 Units: ms FM_MIXER_AGC_RELEASE_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MIX_AGC_RELEASE_MS[15:0] 0x0050 Bit 15:0 Name Function Number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. MIX_AGC_RELEASE_MS[15:0] Default is 80 ms Si475x-A10 and earlier: Range: 4-248 ms. Si475x-A20 and later: Range is 4-4096 ms. Rev. 0.9 87 AN543 Property 0x0707 FM_MIXER_AGC_PD_THRESHOLD The FM_MIXER_AGC_PD_THRESHOLD property sets the high threshold and hysteresis for the mixer peak detector. The high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB below the high threshold the level must drop before the AGC decreases attenuation. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x5103 FM_MIXER_AGC_PD_THRESHOLD 15 14 Bit 15:8 7:0 88 13 12 11 10 9 8 7 6 5 4 3 HIGH[7:0] HYST[7:0] 0x51 0x03 Name 2 1 0 Function HIGH[7:0] Sets the level in dBV at which AGC increases attenuation. HIGH[7:0]: Range 79-93. 79 = 79 dBV. 81 = 81 dBV. 83 = 83 dBV. 85 = 85 dBV. 87 = 87 dBV. 89 = 89 dBV. 91 = 91 dBV. 93 = 93 dBV. HYST[7:0] Sets how many dB below the high threshold the level must drop before the AGC decreases attenuation. HYST[7:0] - Range: 3-6. 3 = 3 dB. 4 = 4 dB. 5 = 5 dB. 6 = 6 dB. Rev. 0.9 AN543 Property 0x0710 FM_AGC_OVERRIDE The FM_AGC_OVERRIDE property overrides the AGC setting by disabling the AGC and forcing the gain to be maximum. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: In Si475x-A30 only, property FM_AGC_PD_CONFIG should be set to 0x0000 when overriding the AGC with the FM_AGC_OVERRIDE property. Doing so removes the automatic AGC from peak detector control. Failure to set FM_AGC_PD_CONFIG when using FM_AGC_OVERRIDE could lead to a conflict which locks the tuner following an FM_TUNE_FREQ command. Default: 0x0000 FM_AGC_OVERRIDE 15 14 13 12 11 10 9 7 6 5 4 3 2 1 0x000 AGC_OVERRIDE[5:0] 0x000 0x000 Bit Name 15:6 Reserved 5:0 8 0 Function Always write 0. AGC_OVERRIDE selects whether the AGC is enabled or disabled. 0 = AGC is enabled. 0x3F = AGC is disabled and set to maximum gain. AGC_OVERRIDE[5:0] Property 0x071B FM_AGC_RSSI_OFFSET The FM_AGC_RSSI_OFFSET property sets the value of the offset applied to the RSSI value in order to account for the front-end gain/loss due to the AGC. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 and before: This property is not available Si475x-A20 and later, Default: 0 Units: dB FM_AGC_RSSI_OFFSET 15 14 Bit 13 12 11 10 9 8 7 6 5 4 3 OFFSET[7:0] RSVD[7:0] 0x00 0x00 2 1 0 Name Function 15:8 OFFSET[7:0] Sets the RSSI offset value to take into account front-end gain/loss. Default is 0. Range is -128 to 127. 7:0 Reserved Always write 0. Rev. 0.9 89 AN543 Property 0x071C FM_MIXER_AGC_PD_THRESHOLD_MAX (Si4754/55/56/57 Only) The FM_MIXER_AGC_PD_THRESHOLD_MAX property sets the maximum threshold for the mixer peak detector when keyed AGC is engaged. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30/A40, Default: 85 Si475x/5xC-A55, Default: 89 FM_MIXER_AGC_PD_THRESHOLD_MAX 15 14 12 11 10 9 8 7 6 5 4 3 0x00 MAX_KEY[7:0] 0x00 0x59 Bit Name 15:8 Reserved 7:0 90 13 MAX_KEY[7:0] 2 1 0 Function Always write to 0. Sets the maximum level in dBuV at which AGC increases attenuation. MAX_KEY [7:0]: Range 79-93 79 = 79 dBV. 81 = 81 dBV. 83 = 83 dBV. 85 = 85 dBV. 87 = 87 dBV. 89 = 89 dBV. 91 = 91 dBV. 93 = 93 dBV Si475x/5xC-A55, Default is 89 dBV. Rev. 0.9 AN543 Property 0x071D FM_AGC_RSSI_MIXER_KEY (Si4754/55/56/57 Only) The FM_AGC_RSSI_MIXER_KEY property sets the RSSI threshold at which the mixer keyed AGC begins to lower or raise the peak detector threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x140E FM_AGC_RSSI_MIXER_KEY 15 14 13 12 11 10 9 8 7 6 5 4 3 2 KEY_HIGH_THR[7:0] KEY_LOW_THR[7:0] 0x14 0x0E 1 0 Bit Name Function 15:8 KEY_HIGH_THR[7:0] Sets the RSSI threshold at which the mixer keyed AGC begins to lower the peak detector threshold. Default is 20 dB. Range: -128 to 127 dB. 7:0 KEY_LOW_THR[7:0] Sets the RSSI threshold at which the mixer keyed AGC begins to raise the peak detector threshold. Default is 14 dB. Range: -128 to 127 dB. Property 0x1006 FM_SEEK_TUNE_CHBW_HOLD_TIME The FM_SEEK_TUNE_CHBW_HOLD_TIME property sets the length of time Channel Filter Bandwidth is held at specified value after Seek or Tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10: This property is not available. Si475x-A20: This feature is not available. Do not write to this property. Si475x-A30 and later, Default: 80 Units: ms FM_SEEK_TUNE_CHBW_HOLD_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 CHBW_HOLD_TIME[15:0] 0x0050 Bit Name Function 15:0 CHBW_HOLD_TIME[15:0] Sets the length of time Channel Filter Bandwidth is held at specified value after Seek or Tune. Default is 80ms. Range is 4-1000. Rev. 0.9 91 AN543 Property 0x1007 FM_TUNE_CHBW The FM_TUNE_CHBW property sets the maximum Channel Filter Bandwidth to allow during normal tune. Narrower Channel Filter Bandwidth could be used based on RSSI, HASSI, LASSI, and ASSI200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 80 Units: kHz FM_TUNE_CHBW 15 14 13 12 11 9 8 7 6 5 4 3 0x00 TUNE_CHBW[7:0] 0x00 0x50 Bit Name 15:8 Reserved 7:0 10 2 1 0 Function Always write to 0. Sets the maximum Channel Filter Bandwidth to allow during normal tune. Narrower Channel Filter Bandwidth could be used based on RSSI, HASSI, LASSI, and ASSI200. Default is 80 kHz. Range is 0-150. TUNE_CHBW[7:0] Property 0x1008 FM_TUNE_AF_CHBW (Si4754/55/56/57 Only) The FM_TUNE_AF_CHBW property sets the Channel Filter Bandwidth during the AF tune/check. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: With Si475x-A40 defaults, the RSSI metric value for AF Check settles within 2 ms. To qualify additional metrics (SNR, Multipath, USN, LASSI, HASSI, ASSI200) users should set Property 0x2007 FM_VALID_AF_TIME to 0x0005 (5 ms) and Property 0x1008 FM_TUNE_AF_CHBW to 0x0050 (80 kHz). Si475x-A20 and earlier: This property is not available Si475x-A30 and A40, Default: 150 Si475x/5xC-A55, Default: 80 Units: kHz FM_TUNE_AF_CHBW 15 92 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 TUNE_AF_CHBW[7:0] 0x00 0x50 Bit Name 15:8 Reserved 7:0 TUNE_AF_CHBW[7:0] 1 0 Function Always write to 0. Sets the maximum Channel Filter Bandwidth to allow during AF tune. Si475x/5xC-A55, Default is 80 kHz. Range is 0-150. Rev. 0.9 AN543 Property 0x1100 FM_SEEK_BAND_BOTTOM The FM_SEEK_BAND_BOTTOM property sets the bottom of the FM band for seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 8750 Units: 10 kHz FM_SEEK_BAND_BOTTOM 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 FMSKFREQL[15:0] 0x222E Bit Name 15:0 Function FMSKFREQL[15:0] Sets the bottom of the FM band for seek. Default is 8750. Range: 6400-10800, 64.0 MHz to 108.0 MHz. Range: 8750-10790, Worldwide FM excluding Japan. Range: 6580-7400, OIRT FM. Range: 7600-9000, Japan FM. Property 0x1101 FM_SEEK_BAND_TOP The FM_SEEK_BAND_TOP property sets the top of the FM band for seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 10790 Si475x/5xC-A55, Default:10800 Units: 10 kHz FM_SEEK_BAND_TOP 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 FMSKFREQH[15:0] 0x2A30 Bit 15:0 Name FMSKFREQH[15:0] Function Sets the top of the FM band for seek. Si475x/5xC-A55 Default is 10800. Range: 6400-10800, 64.0 MHz to 108.0 MHz. Range: 8750-10790, Worldwide FM excluding Japan. Range: 6580-7400, OIRT FM. Range: 7600-9000, Japan FM. Rev. 0.9 93 AN543 Property 0x1102 FM_SEEK_FREQUENCY_SPACING The FM_SEEK_FREQUENCY_SPACING property selects frequency spacing for FM seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 100 kHz. Default: 10 Units: 10 kHz FM_SEEK_FREQUENCY_SPACING 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0x000 FMSKSPACE[4:0] 0x000 0x0A Bit Name 15:5 Reserved 4:0 FMSKSPACE[4:0] 0 Function Always write 0. Selects frequency spacing for FM seek. Default is 10. Range is 1-31. Property 0x1104 FM_SEEK_CHBW The FM_SEEK_CHBW property sets the Channel Filter Bandwidth during seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and A40, Default: 110 Si475x/5xC-A55, Default: 80 Units: kHz FM_SEEK_CHBW 15 14 12 11 10 9 8 7 6 5 4 3 0x00 SEEK_CHBW[7:0] 0x00 0x50 Bit Name 15:8 Reserved 7:0 94 13 SEEK_CHBW[7:0] 2 1 Function Always write to 0. Sets the maximum Channel Filter Bandwidth to allow during seek. Si475x/5xC-A55, Default is 80 kHz. Range is 0-150. Recommended value for 50 or 100 kHz spacing is 80 kHz. Recommended value for 200 kHz spacing is 110 kHz. Rev. 0.9 0 AN543 Property 0x1200 FM_RSQ_INTERRUPT_SOURCE The FM_RSQ_INTERRUPT_SOURCE property configures interrupt related to Received Signal Quality metrics. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 FM_RSQ_INTERRUPT_SOURCE 15 14 13 12 11 10 9 8 0x00 7 6 5 4 3 2 1 0 MULTHINT MULTLINT ISSIHINT ISSILINT SNRHINT SNRLINT RSSIHINT RSSILINT 0x00 0 Bit Name 15:8 Reserved 0 0 0 0 0 0 0 Function Always write 0. 7 MULTHINT 0: Disable Interrupt. 1:Enable interrupt if Multipath level goes above the threshold set by FM_RSQ_MULTIPATH_HIGH_THRESHOLD. 6 MULTLINT 0: Disable Interrupt. 1: Enable interrupt if Multipath level falls below the threshold set by FM_RSQ_MULTIPATH_LOW_THRESHOLD. 5 ISSIHINT 0: Disable Interrupt. 1: Enable interrupt if ISSI goes above the threshold set by FM_RSQ_ISSI_HIGH_THRESHOLD. 4 ISSILINT 0: Disable Interrupt. 1: Enable interrupt if ISSI falls below the threshold set by FM_RSQ_ISSI_LOW_THRESHOLD. 3 SNRHINT 0: Disable Interrupt. 1: Enable interrupt if SNR goes above the threshold set by FM_RSQ_SNR_HIGH_THRESHOLD. 2 SNRLINT 0: Disable Interrupt. 1: Enable interrupt if SNR falls below the threshold set by FM_RSQ_SNR_LOW_THRESHOLD. 1 RSSIHINT 0: Disable Interrupt. 1: Enable interrupt if RSSI goes above the threshold set by FM_RSQ_RSSI_HIGH_THRESHOLD. 0 RSSILINT 0: Disable Interrupt. 1: Enable interrupt if RSSI falls below the threshold set by FM_RSQ_RSSI_LOW_THRESHOLD. Rev. 0.9 95 AN543 Property 0x1201 FM_RSQ_SNR_HIGH_THRESHOLD The FM_RSQ_SNR_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if the SNR is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 127 Units: dB FM_RSQ_SNR_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 0x00 SNRH[7:0] 0x00 0x7F Bit Name 15:8 Reserved 7:0 SNRH [7:0] 2 1 0 Function Write 0 for (+) values and 0xFF for (-) values. Sets the high threshold, which triggers the RSQ interrupt if the SNR is above this threshold. Default is 127 dB. Range is -128 to 127 in steps of 1 dB. Property 0x1202 FM_RSQ_SNR_LOW_THRESHOLD The FM_RSQ_SNR_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the SNR is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: -128 Units: dB FM_RSQ_SNR_LOW_THRESHOLD 15 96 14 13 12 11 10 9 8 7 6 5 4 3 0xFF SNRL[7:0] 0xFF 0x80 Bit Name 15:8 Reserved 7:0 SNRL [7:0] 2 1 0 Function Write 0 for (+) values and 0xFF for (-) values. Sets low threshold, which triggers the RSQ interrupt if the SNR is below this threshold. Default is -128 dB. Range is -128 to 127 in steps of 1 dB. Rev. 0.9 AN543 Property 0x1203 FM_RSQ_RSSI_HIGH_THRESHOLD The FM_RSQ_RSSI_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if RSSI is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 127 Units: dBV FM_RSQ_RSSI_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 0x00 0x00 Bit Name 15:8 Reserved 7:0 RSSIH [7:0] 4 3 2 1 0 RSSIH[7:0] 0x7F Function Write 0 for (+) values and 0xFF for (-) values. Sets high threshold, which triggers the RSQ interrupt if the RSSI is above this threshold. Default is 127 dBV. Range is -128 to 127 in steps of 1 dB. Property 0x1204 FM_RSQ_RSSI_LOW_THRESHOLD The FM_RSQ_RSSI_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the RSSI is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: -128 Units: dBV FM_RSQ_RSSI_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 0xFF RSSIL[7:0] 0xFF 0x80 Bit Name 15:8 Reserved 7:0 RSSIL [7:0] 2 1 0 Function Write 0 for (+) values and 0xFF for (-) values. Sets low threshold, which triggers the RSQ interrupt if the RSSI is below this threshold. Default is -128 dBV. Range is -128 to 127 in steps of 1 dB. Rev. 0.9 97 AN543 Property 0x1205 FM_RSQ_ISSI_HIGH_THRESHOLD The FM_RSQ_ISSI_HIGH_THRESHOLD property sets the Image Signal Strength Indicator high threshold, which triggers the RSQ interrupt if the ISSI is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 127 FM_RSQ_RSSI_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 0x00 HIGH[7:0] 0x00 0x7F 2 1 Bit Name 15:8 Reserved Always write 0. 7:0 HIGH[7:0] High threshold for ISSI interrupt in dBr relative to the desired signal. Default is 127 dBr. Range is -128 to 127. 0 Function Property 0x1206 FM_RSQ_ISSI_LOW_THRESHOLD The FM_RSQ_ISSI_LOW_THRESHOLD property sets the Image Signal Strength Indicator low threshold, which triggers the RSQ interrupt if the ISSI is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: -128 FM_RSQ_ISSI_LOW_THRESHOLD 15 98 14 13 12 11 10 9 8 7 6 5 4 3 0x00 LOW[7:0] 0x00 0x80 2 1 Bit Name Function 15:8 Reserved Always write 0. 7:0 LOW[7:0] Low threshold for ISSI interrupt in dBr relative to the desired signal. Default is -128 dBr. Range is -128 to 127. Rev. 0.9 0 AN543 Property 0x1207 FM_RSQ_MULTIPATH_HIGH_THRESHOLD The FM_RSQ_MULTIPATH_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if Multipath is above this threshold. Multipath is a measure of AM modulation and can exceed 100%. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 127 FM_RSQ_MULTIPATH_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 0x000 MULTH[6:0] 0x000 0x7F Bit Name 15:7 Reserved 6:0 MULTH [6:0] 2 1 0 Function Always write 0. Sets the high threshold, which triggers the RSQ interrupt if Multipath is above this threshold. Default is 127. Range is 0-127. Property 0x1208 FM_RSQ_MULTIPATH_LOW_THRESHOLD The FM_RSQ_MULTIPATH_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if Multipath is below this threshold. Multipath is a measure of AM modulation and can exceed 100%. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 FM_RSQ_MULTIPATH_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 0x000 MULTL[6:0] 0x000 0x00 Bit Name 15:7 Reserved 6:0 MULTL[6:0] 2 1 0 Function Always write 0. Sets low threshold, which triggers the RSQ interrupt if Multipath is below this threshold. Default is 0. Range is 0-127. Rev. 0.9 99 AN543 Property 0x1300 FM_ACF_INTERRUPT_SOURCE The FM_ACF_INTERRUPT_SOURCE property enables the ACF interrupt sources. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 FM_ACF_INTERRUPT_SOURCE 15 14 13 12 11 10 9 8 7 0x000 5 4 3 2 1 0 CHBWH_INT BLEND_INT HIBLEND_INT HICUT_INT CHBW_INT SOFTMUTE_INT 0x000 0 Bit Name 15:6 Reserved 0 0 0 0 0 Function Always write 0. CHBWH_INT (Available on Si475x-A40 only) When set, enables the Channel Filter Bandwidth High interrupt. Default is 0. 0 = The Channel Bandwidth interrupt is disabled 1 = The Channel Bandwidth interrupt is enabled 4 BLEND_INT When set, enables the blend interrupt. Default is 0. 0 = The blend interrupt is disabled. 1 = The blend interrupt is enabled. 3 HIBLEND_INT 2 HICUT_INT When set, enables the HICUT interrupt. Default is 0. 0 = The HICUT interrupt is disabled. 1 = The HICUT interrupt is enabled. 1 CHBW_INT When set, enables the Channel Filter Bandwidth Interrupt. Default is 0. 0 = The Channel Filter Bandwidth interrupt is disabled. 1 = The Channel Filter Bandwidth interrupt is enabled. 5 0 100 6 SOFTMUTE_INT When set, enables the HIBLEND interrupt. Default is 0. 0 = The HIBLEND interrupt is disabled. 1 = The HIBLEND interrupt is enabled. When set, enables the softmute interrupt. Default is 0. 0 = The softmute interrupt is disabled. 1 = The softmute interrupt is enabled. Rev. 0.9 AN543 Property 0x1301 FM_ACF_SM_THRESHOLD The FM_ACF_SM_THRESHOLD property sets the softmute interrupt threshold in dB. When softmute attenuation rises above the level set by this property and the SOFTMUTE_INT interrupt is enabled through the FM_ACF_INTERRUPT_SOURCE property, the SOFTMUTE_INT interrupt will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in the powerup mode. Default: 31 Units: dB FM_ACF_SM_THRESHOLD 15 14 13 12 11 9 8 7 6 5 4 3 2 1 0x000 SMATTN_THRESH[4:0] 0x000 0x1F Bit Name 15:5 Reserved 4:0 10 SMATTN_THRESH[4:0] 0 Function Always write 0. Softmute interrupt threshold in dB, which triggers the softmute interrupt when the softmute attenuation rises above this level. Default is 31 dB Range is 0-31 dB. Rev. 0.9 101 AN543 Property 0x1302 FM_ACF_CHBW_THRESHOLD The FM_ACF_CHBW_THRESHOLD property sets the Channel Filter Bandwidth interrupt threshold in units of kHz. When the Channel Filter Bandwidth falls below this threshold and the CHBW_INT interrupt is enabled through the FM_ACF_INTERRUPT_SOURCE property, the CHBW_INT interrupt will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 Units: kHz FM_ACF_CHBW_THRESHOLD 15 Bit 14 13 12 11 10 9 8 7 6 5 4 3 2 CHBW_THRESH_HIGH[7:0] CHBW_THRESH_LOW[7:0] 0x00 0x00 Name 1 0 Function 15:8 (Available in Si475x-A40 and later) Channel Filter Bandwidth High interrupt threshold in units of kHz, which triggers the Channel Filter Bandwidth High Interrupt when the channel filCHBW_THRESH_HIGH[7:0] ter bandwidth rises above this threshold. Default is 0 kHz. Range is 0-255 kHz 7:0 Channel Filter Bandwidth interrupt threshold in units of kHz, which triggers the Channel Filter Bandwidth Low interrupt when the Channel Filter CHBW _THRESH_LOW[7:0] Bandwidth falls below this threshold. Default is 0 kHz Range is 0-255 kHz. 102 Rev. 0.9 AN543 Property 0x1303 FM_ACF_HICUT_THRESHOLD The FM_ACF_HICUT_THRESHOLD property sets the HICUT interrupt threshold in units of 100 Hz. When the HICUT cutoff frequency falls below this threshold and the HICUT_INT interrupt is enabled through the FM_ACF_INTERRUPT_SOURCE property, the HICUT_INT interrupt will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 Units: 100 Hz FM_ACF_HICUT_THRESHOLD 15 14 13 12 10 9 8 7 6 5 4 3 2 0x00 HICUT_THRESH[7:0] 0x00 0x00 Bit Name 15:8 Reserved 7:0 11 HICUT_THRESH[7:0] 1 0 Function Always write 0. HICUT interrupt threshold in units of 100 Hz, which triggers the HICUT Interrupt when the HICUT cutoff frequency falls below this threshold. Default is 0. Range is 0-200. Rev. 0.9 103 AN543 Property 0x1304 FM_ACF_HIBLEND_THRESHOLD The FM_ACF_HIBLEND_THRESHOLD property sets the HIBLEND interrupt threshold in units of 100 Hz. When the HIBLEND cutoff frequency falls below this threshold and the HIBLEND_INT interrupt is enabled through the FM_ACF_INTERRUPT_SOURCE property, the HIBLEND_INT interrupt will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 Units: 100 Hz FM_ACF_HIBLEND_THRESHOLD 15 14 13 12 9 8 7 6 5 4 3 2 HIBLEND_THRESH[7:0] 0x00 0x00 Name 15:8 Reserved 104 10 0x00 Bit 7:0 11 1 0 Function Always write 0. HIBLEND interrupt threshold in units of 100 Hz, which triggers the HIBLEND Interrupt when the HIBLEND cutoff frequency falls below this HIBLEND_THRESH[7:0] threshold. Default is 0. Range is 0-200. Rev. 0.9 AN543 Property 0x1305 FM_ACF_BLEND_THRESHOLD The FM_ACF_BLEND_THRESHOLD property sets the interrupt trigger threshold for stereo blend. The threshold is expressed as a percentage in terms of L minus R (L - R) gain factor K. When the L-R gain falls below this threshold and the BLEND_INT is enabled through the FM_ACF_INTERRUPT_SOURCE property, the BLEND_INT will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: Stereo Separation S = (1 + K) / (1 - K), where K is the L minus R gain factor. Stereo separation of 1 implies mono mode and stereo separation of >1 implies that the part is in stereo with up to 20 log(S) dB of stereo separation. This property expresses the threshold value of K as a percentage. For example, value 0x0032 = a K of 50%, or a stereo separation of S = (1.5 / 0.5) = 3. The interrupt would then trigger at 20 log(3) = 9.5 dB of stereo separation. Default: 0 Units: % L-R gain FM_ACF_BLEND_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x000 BLEND_THRESH[6:0] 0x000 0x00 1 0 Bit Name Function 15:7 Reserved Always write 0. 6:0 BLEND_ THRESH [6:0] Stereo Blend Interrupt threshold in units of % L-R gain, which triggers the Blend threshold interrupt when L-R gain falls below this threshold. Default is 0%. Range is 0-100%. Rev. 0.9 105 AN543 Property 0x1306 FM_ACF_CONTROL_SOURCE The FM_ACF_CONTROL_SOURCE property determines the controlling metric for ACF features. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 1 Si475x/5xC-A55, Default: 3 FM_ACF_CONTROL_SOURCE 15 14 13 12 11 10 9 8 7 6 5 4 3 0x0000 2 AFC_SM DEV_CHBW 0x0000 Bit Name 15:1 Reserved 1 0 0 0 USE_MULTPATH 1 Function Always write 0. (Only applicable to Si475x-A20 and later) When set, softmute will be triggered by an AFC rail. Default is 0. 2 AFC_SM 0 = Do not use AFC rail to force a softmute. 1 = Use AFC rail to force maximum softmute attenuation set by FM_SOFT_MUTE_MAX_ATTENUATION property (0x400). (Only applicable to Si475x-A20 and later) When set, STRONGDEV will be used instead of RSSI as the controlling metric for Channel Filter Bandwidth. Default is 0. 1 DEV_CHBW 0 = Use RSSI as the controlling metric for weak signal Channel Filter Bandwidth control. 1 = Use STRONGDEV as the controlling metric for weak signal Channel Filter Bandwidth control. 0 106 (Only applicable to Si475x/5xC-A55 and later) When cleared to 0, ASSI200DEV will be used instead of Multipath as the controlling USE_MULTPATH metric for softmute. Default is 1. 0 = Use ASSI200DEV as the controlling metric for softmute. 1 = Use MultiPath as the controlling metric for softmute. Rev. 0.9 AN543 Property 0x1307 FM_ACF_HOLD_TIME The FM_ACF_HOLD_TIME property sets the ACF hold time after tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, this property is not available. Si475x/5xC-A55, Default: 0x0064 Units: ms FM_ACF_HOLD_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 0x00 DELAY[7:0] 0x00 0x64 Bit Name 15:8 Reserved 7:0 DELAY [7:0] 2 1 0 Function Always write 0. Sets the ACF hold time after tune in millisecond. Default is 100 ms, Range is 4 ~ 255 ms. Recommended minimum value is 8 ms. Rev. 0.9 107 AN543 Property 0x2000 FM_VALID_MAX_TUNE_ERROR The FM_VALID_MAX_TUNE_ERROR property sets the maximum freq error allowed in units of 2 ppm before setting the AFC rail indicator (AFCRL). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 75 (150 ppm) Units: 2 ppm FM_VALID_MAX_TUNE_ERROR 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 FMMAXTUNEERR[7:0] 0x00 0x4B Bit Name 15:8 Reserved 7:0 FMMAXTUNEERR [7:0] 1 0 Function Always write 0. Sets the maximum freq error allowed in units of 2 ppm before setting the AFC rail indicator (AFCRL). Range is 0-126. Property 0x2001 FM_VALID_RSSI_TIME The FM_VALID_RSSI_TIME property sets the amount of time in milliseconds to allow the RSSI metric to settle before evaluating. This parameter is valid only if TUNEMODE[1:0] (FM_TUNE_FREQ) is set to 0. The minimum RSSI settling delay is 3 milliseconds. The reliability of the valid bit for identifying valid stations relies on this parameter being set properly. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 6 Units: ms FM_VALID_RSSI_TIME 15 108 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SSIVALTIME[5:0] 0x00 0x06 Bit Name 15:6 Reserved 5:0 SSIVALTIME[5:0] 1 0 Function Always write 0. Validation time in milliseconds. Default is 6 ms. Range is 3-63 ms in Si475x-A30 and earlier. Range is 3-127 ms in Si475x-A40 and later. Rev. 0.9 AN543 Property 0x2002 FM_VALID_SNR_TIME The FM_VALID_SNR_TIME property sets the amount of time in milliseconds to allow the SNR metric to settle before evaluating. This parameter is valid only if TUNEMODE[1:0] (FM_TUNE_FREQ) is set to 0. The minimum SNR settling delay is 4 ms. The reliability of the valid bit for identifying valid stations relies on this parameter being set properly. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 18 Units: ms FM_VALID_SNR_TIME 15 14 13 12 11 10 8 7 6 5 4 3 2 0x00 SNRVALTIME[5:0] 0x00 0x12 Bit Name 15:6 Reserved 5:0 9 1 0 Function Always write 0. Validation time in milliseconds. Default is 18 ms. Range is 4-63 ms in Si475x-A30 and earlier. Range is 4-127 ms in Si475x-A40 and later. SNRVALTIME[5:0] Rev. 0.9 109 AN543 Property 0x2003 FM_VALID_SNR_THRESHOLD The FM_VALID_SNR_THRESHOLD property sets the SNR threshold for a valid FM Seek/Tune. If the desired channel SNR is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 8 Units: dB FM_VALID_SNR_THRESHOLD 15 Bit 14 13 12 11 10 9 8 7 6 5 4 3 FMVALUSN[7:0] FMVALSNR[7:0] 0x00 0x08 2 1 0 Name Function 15:8 FMVALUSN[7:0] (Available in Si475x-A40 and later) Sets the USN threshold for a valid FM Seek/Tune. Default is 0 dBFS. Range is 0 to 127 in units of negative -dBFS. (0 is full scale, 127 is 127 dB down from full scale.) 0 = USN is not used as a criterion in determining the validity of a station. (In Si475x-A30 and earlier, this field should be the continued SIGN of FMVALSNR. That is, it should be 0x00 for positive (+) values and 0xFF for negative (-) values.) 7:0 FMVALSNR [7:0] Sets the SNR threshold for a valid FM Seek/Tune. Default is 8 dB. Range is -128 to 127 in steps of 1 dB. -128 = SNR is not used as a criterion in determining the validity of a station. 110 Rev. 0.9 AN543 Property 0x2004 FM_VALID_RSSI_THRESHOLD The FM_VALID_RSSI_THRESHOLD property sets the RSSI threshold for a valid FM Seek/Tune. If the desired channel RSSI is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 12 Units: dBV FM_VALID_RSSI_THRESHOLD 15 14 13 12 10 9 8 7 6 5 4 3 0x00 FMVALRSSI[7:0] 0x00 0x0C Bit Name 15:8 Reserved 7:0 11 2 1 0 Function Always write 0. FMVALRSSI[7:0] Sets the RSSI threshold for a valid FM Seek/Tune. Default is 12 dBV. Range is -128 to 127 in steps of 1 dB. -128 = RSSI is not used as a criterion in determining the validity of a station. Property 0x2005 FM_VALID_ISSI_THRESHOLD (Si4754/55/56/57 Only) The FM_VALID_ISSI_THRESHOLD property sets the ISSI threshold for valid FM Seek/Tune. If the desired channel ISSI is below this threshold, then it is considered valid. If the desired channel ISSI is above this threshold, then the tuner will retune after switching the injection side and revalidate the station. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A30, Default: 30 All others: This feature is not available.Units: dB FM_VALID_ISSI_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 0x00 FMVALISSI[7:0] 0x00 0x1E Bit Name 15:8 Reserved 7:0 FMVALISSI[7:0] 2 1 0 Function Always write to 0. Sets the ISSI threshold for valid FM Seek/Tune. Default is 30 dB. Range is -128 to 127 dB. Rev. 0.9 111 AN543 Property 0x2006 FM_VALID_MULT_THRESHOLD The FM_VALID_MULT_THRESHOLD sets the multipath threshold for a valid FM Seek/Tune. If the desired channel multipath is below this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 and earlier: This property is not available. Si475x-A20 and later, Default: 100 FM_VALID_MULT_THRESHOLD 15 14 13 12 11 9 8 7 6 5 4 3 0x00 FMVALMULT[7:0] 0x00 0x64 Bit Name 15:8 Reserved 7:0 FMVALMULT[7:0] 112 10 Function Always write 0. FM Seek/Tune Received Multipath Threshold. Default is 100%. Range is 0-100%. Rev. 0.9 2 1 0 AN543 Property 0x2007 FM_VALID_AF_TIME (Si4754/55/56/57 Only) The FM_VALID_AF_TIME property sets the amount of time in milliseconds to allow the RSSI and SNR metrics to settle before evaluating during an AF check/tune. This parameter is valid only if TUNEMODE[1:0] (FM_TUNE_FREQ) is set to 2 or 3. The reliability of the valid bit for identifying valid stations relies on this parameter being set properly. Setting this property to a value lower than 4 will result in the metric not being measured correctly at tune time. To disable metric as a tune qualifier set the validation time to 0 and set the validation threshold to the minimum value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: With Si475x-A40 defaults, the RSSI metric value for AF Check settles within 2 ms. To qualify additional metrics (SNR, Multipath, USN, LASSI, HASSI, ASSI200) users should set Property 0x2007 FM_VALID_AF_TIME to 0x0005 (5 ms) and Property 0x1008 FM_TUNE_AF_CHBW to 0x0050 (80 kHz). Si475x-A10, it is not available. Si475x-A20 and Si475x-A30, Default: 5 Si475x-A40 and later, Default: 2 Units: ms FM_VALID_AF_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 Reserved AFVALTIME[5:0] 0x000 0x02 Bit Name 15:6 Reserved 5:0 AFVALTIME[5:0] 1 0 Function Always write 0. Validation time for AF tune. For RSSI only check, range is 3-63 ms. For RSSI and SNR check, range is 0-63 ms. Rev. 0.9 113 AN543 Property 0x2008 FM_VALID_AF_RDS_TIME (Si4754/55/56/57 Only) The FM_VALID_AF_RDS_TIME property sets the maximum amount of time in milliseconds to allow RDS to acquire PI code when performing AF tune with non-zero FM_VALID_AF_PI property (0x2009). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 120 Units: ms FM_VALID_AF_RDS_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 AFVALPITIME[15:0] 0x0078 Bit Name Function 15:0 AFVALPITIME[15:0] Validation time for AF tune with PI code check. Default is 120 ms. Range is 0-32767 ms. Property 0x2009 FM_VALID_AF_PI (Si4754/55/56/57 Only) The FM_VALID_AF_PI property sets PI code used for validating an AF tune. If set to 0x0000, then PI code check is not performed. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x0000 FM_VALID_AF_PI 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 AFVALPI[15:0] 0x0000 114 Bit Name Function 15:0 AFVALPI[15:0] Sets PI code used for validating an AF tune. If set to 0x0000, then PI code check is not performed. Default is 0x0000. Rev. 0.9 AN543 Property 0x200A FM_VALID_ASSI_THRESHOLD (Si4754/55/56/57 Only) The FM_VALID_ASSI_THRESHOLD property sets the ASSI threshold for valid FM Seek/Tune. If the desired channel ASSI is below this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x503C Units: dB FM_VALID_ASSI_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0 FMVALASSI200[6:0] 0 FMVALASSI100[6:0] 0 0x50 0 0x3C Bit Name 15 Reserved 14:8 FMVALASSI200[6:0] 7 Reserved 6:0 FMVALASSI100[6:0] 1 0 Function Always write to 0. Sets the ASSI200 threshold for valid FM Seek/Tune. Default is 80 dB. Range is 0 to 127 dB. Always write to 0. Sets the max(HASSI,LASSI) threshold for valid FM Seek/Tune. Default is 60 dB. Range is 0 to 127 dB. Property 0x200B FM_VALID_AF_PI_MASK (Si4754/55/56/57 Only) The FM_VALID_AF_PI_MASK property sets the bit mask for comparing the PI code to the FM_VALID_AF_PI property (0x2009). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0xFFFF FM_VALID_AF_PI_MASK 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 AFVALPIMASK[15:0] 0xFFFF Bit Name Function 15:0 AFVALPIMASK[15:0] Sets the bit mask for comparing the PI code to the FM_VALID_AF_PI property (0x2009). Default is 0xFFFF. Rev. 0.9 115 AN543 Property 0x200C FM_VALID_FREQOFF_SCALE The FM_VALID_FREQOFF_SCALE sets the units in Hz for the FM_RSQ_STATUS response FREQOFF metric, as well as FM_VALID_MAX_TUNE_ERROR. (For example, if FM_VALID_FREQOFF_SCALE is set to 100, then FM_VALID_MAX_TUNE_ERROR will have units of 100 Hz per property value step.) The default is to use units of binary ppm instead of any number of Hz. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. In Si475x-A30 and earlier, FREQOFF is always in units of bppm (binary ppm, or 2 ppm). Si475x-A30 and earlier: This property is not available. Si475x-A40 and later, Default: 0 Units: Hz FM_VALID_FREQOFF_SCALE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SCALE[15:0] 0x0000 Bit Name 15:8 Function Sets the units in Hz for the frequency offset metric and the FM_VALID_MAX_TUNE_ERROR. The recommended value for FM is 1000 Hz. Default is 0. 0 = Use units of bppm. SCALE[15:0] Property 0x200D FM_VALID_FREQOFF_FILTER The FM_VALID_FREQOFF_FILTER sets the number of FREQOFF samples averaged by the metric filter before reporting FREQOFF as part of FM_RSQ_STATUS. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A30 and earlier: This property is not available. Si475x-A40 and later, Default: 100 FM_VALID_FREQOFF_FILTER 15 14 12 11 10 9 8 7 6 5 4 3 0x00 FILTER[7:0] 0x00 0x64 Bit Name 15:8 Reserved 7:0 116 13 FILTER[7:0] 2 1 0 Function Always write 0. The number of FREQOFF values that are averaged when reporting the value in FM_RSQ_STATUS. (Values below 10 will begin to track audio and are not recommended. If low-cut is being used then the minimum value will need to be increased accordingly to avoid tracking low frequency audio.) Default is 100 samples. Range is 0-127. Rev. 0.9 AN543 Property 0x2100 FM_NB_DETECT_THRESHOLD The FM_NB_DETECT_THRESHOLD property sets the threshold for detecting impulses in dB above the noise floor. The noise blanker can be disabled by setting the noise blanker detect threshold to 0.The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 18 Units: dB FM_NB_DETECT_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 DETECT_THRESHOLD[15:0] 0x0012 Bit Name 15:0 Function DETECT_THRESHOLD[15:0] Sets the threshold for detecting impulses in dB above the noise floor. Default is 18 dB Range is 0-90 dB. To disable the noise blanker, set the DETECT_THRESHOLD to 0. Property 0x2101 FM_NB_INTERVAL The FM_NB_INTERVAL property sets the interval that original samples are replaced by interpolated clean samples. The noise blanker can be disabled by setting the noise blanker detect threshold to 0.The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 5 Units: none FM_NB_INTERVAL 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NB_INTERVAL[15:0] 0x0005 Bit 15:0 Name NB_INTERVAL[15:0] Function Sets the interval in number of audio samples that original samples are replaced by interpolated clean samples. Default is 5. Range is 1-20. Rev. 0.9 117 AN543 Property 0x2103 FM_NB_SECONDARY_DETECT_THRESHOLD The FM_NB_SECONDARY_DETECT_THRESHOLD property sets the threshold for secondary (IF) noise blanker. The noise blanker is triggered when the IF signal's average-to-peak ratio is no more than FM_NB_SECONDARY_DETECT_THRESHOLD / 32767. The recommended average-to-peak ratio 10%, which is equivalent to setting this property to 32767. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Si475x-A40 and earlier, this property is not available. Si475x/5xC-A55, Default: 0 Units: None FM_NB_SECONDARY_DETECT_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SECONDARY_DETECT_THRESHOLD[15:0] 0x0000 Bit 15:0 118 Name Function SECONDARY_DETECT_ THRESHOLD[15:0] The percentage is a fractional Q15 number. Recommended setting is 14%, which is equivalent to setting this property to 0x11EC. Default is 0. Range is 0-32767. 0 = Disable the secondary noise blanking (IF) engine. Rev. 0.9 AN543 Property 0x2105 FM_NB_WEAK_DETECT_THRESHOLD The FM_NB_WEAK_DETECT_THRESHOLD property sets the threshold for detecting impulses. The threshold is set in Q15 format as a linear scaling factor between the average (noise floor) and the pulse peak. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 13568, Si475x/5xC-A55, Default: 7537 FM_NB_WEAK_DETECT_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WEAK_DETECT_THRESHOLD[15:0] 0x3500 Bit 15:0 Name Function WEAK_DETECT_THRESHOLD[15:0] Sets the detection threshold for the weak signal blanker. If (measured audio level average/peak audio level) < WEAK_DETECT_THRESHOLD/32767, then the blanker is engaged. Higher settings blank more aggressively. Si475x/5xC-A55; Default is 7537. Range is 0-32767 Property 0x2106 FM_NB_STRONG_SIGNAL_SHUTOFF The RSSI based shutoff threshold. Used to turn off the noise blanker under strong signal conditions. Default: 50 Units: dBuV FM_NB_STRONG_SIGNAL_SHUTOFF 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 RSSI_THRESH [6:0] 0x00 0x32 Bit Name 15:7 Reserved 6:0 RSSI_THRESH[6:0] 1 0 Function Always write 0. default: 0x32 RSSI level at which the noise blanker is effectively off. Range: 0-127 RSSI level in dB. Rev. 0.9 119 AN543 Property 0x2109 FM_NB_MODE_CONTROL The FM_NB_MODE_CONTROL property sets high-level control for the FM noise blanker. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0 FM_NB_MODE_CONTROL 15 14 13 12 11 Bit Name 15:1 Reserved 0 10 9 8 7 6 5 4 3 2 1 0 0x0000 USE_RSSI 0x0000 0 Function Always write 0. When set, selects noise blanker to use based on RSSI instead of SNR. 0 = SNR metric controls automatic noise blanker selection. 1 = RSSI metric controls automatic noise blanker selection. USE_RSSI Property 0x210A FM_NB_WEAK_BLANK_INTERVAL The FM_NB_WEAK_BLANK_INTERVAL sets the number of samples to be blanked by the weak-signal blanker upon detection of a noise pulse. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 5 FM_NB_WEAK_BLANK_INTERVAL 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 WEAK_BLANK_INTERVAL[15:0] 0x0005 Bit 15:0 120 Name WEAK_BLANK_INTERVAL[15:0] Function Number of samples that are replaced by interpolated clean samples in the weak noise blanker. Default is 5. Range is 0-32767. Rev. 0.9 0 AN543 Property 0x210B FM_NB_STRONG_WEAK_SWITCH The FM_NB_STRONG_WEAK_SWITCH sets the threshold for switching between the weak signal and strong signal noise blanker. (Particularly strong noise pulses can interfere with signal metrics, which can in turn interfere with noise pulse detection. The weak signal blanker operates under most signal conditions, while the strong signal blanker operates under conditions that would normally disturb signal quality metrics and prevent proper pulse detection.) The difference between HIGH and LOW is the hysteresis of the switch. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x0B09 FM_NB_STRONG_WEAK_SWITCH 15 14 13 12 11 10 9 8 7 6 5 4 3 0 HIGH[6:0] 0 LOW[6:0] 0 0x0B 0 0x09 2 1 Bit Name 15 Reserved Always write 0. 14:8 HIGH[6:0] SNR/RSSI level above which the strong noise blanker is used. Default is 11 dB/dBuV. Range is -127 to 127 dB/dBV. 7 Reserved Always write 0. LOW[6:0] SNR/RSSI level below which the weak noise blanker is used. Default is 9 dB/dBV. Range is -127 to 127 dB/dBuV. 6:0 0 Function Rev. 0.9 121 AN543 Property 0x2111 FM_NB_CIMP_HICUT_LIMIT The FM_NB_CIMP_HICUT_LIMIT property sets the HICUT multipath threshold when continuous impulses are detected. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: this property is not available. Si475x/5xC-A55, Default: 0x0A14 FM_CHBW_SQ_MIN_MAX 15 122 14 13 12 11 10 9 8 7 6 5 4 3 XMAX[7:0] XMIN[7:0] 0x0A 0x14 2 1 0 Bit Name Function 15:8 XMAX [7:0] Sets the Multipath level at which HICUT reaches max band limiting on the L+R channel based on cutoff frequency set by property 0x2112. Si475x/5xC-A55, Default is 10. Range is 0-127%. 7:0 XMIN [7:0] Sets the Multipath level at which HICUT begins to band limit on the L+R channel based on cutoff frequency set by property 0x2112. Si475x/5xC-A55, Default is 20. Range is 0-127%. Rev. 0.9 AN543 Property 0x2112 FM_NB_CIMP_HICUT_FREQ The FM_NB_CIMP_HICUT_FREQ property sets the HiCut cut-off frequency settings when continuous impulses are detected. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available. Si475x/5xC-A55, Default: 0x6401 Unit: 100 Hz FM_NB_CIMP_HICUT_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 YMAX[7:0] YMIN[7:0] 0x64 0x01 Bit Name 15:8 YMAX[7:0] Sets the maximum cutoff frequency. Range is 0-18 kHz. Si475x/5xC-A55, Default is 10 kHz. 7:0 YMIN[7:0] Sets the minimum stereo separation. Range is 0-18 kHz. Si475x/5xC-A55, Default is 100 Hz. 2 1 0 Function Rev. 0.9 123 AN543 Property 0x2113 FM_NB_CIMP_HICUT_ATTACK The FM_NB_CIMP_HICUT_ATTACK property sets the transition time for which the HICUT mitigation engine lowers the cutoff frequency based on Multipath when continuous impulses are detected. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available. Si475x/5xC-A55, Default: 0x0001 Unit: ms FM_NB_CIMP_HICUT_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0001 Bit Name Function 15:0 ATTACK[15:0] Sets the transition time for which the HICUT mitigation engine lowers the cutoff frequency based on Multipath. Si475x/5xC-A55 Default is 1 ms. Range is 1-32767 ms. Property 0x2114 FM_NB_CIMP_HICUT_RELEASE The FM_NB_CIMP_HICUT_RELEASE property sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on Multipath when continuous impulses are detected. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available. Si475x/5xC-A55 Default: 0x0008 Unit: ms FM_NB_CIMP_HICUT_RELEASE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0008 124 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on Multipath. Si475x/5xC-A55 Default is 8 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x2115 FM_NB_CIMP_DETCNTR The FM_NB_CIMP_DETCNTR property sets the continuous impulse detection counter setting. NCONT sets how many continuous 1ms timeslots with impulse detected will trigger continuous flag, NSTEP sets accumulative step, this determines release time for continuous flag if no impulses was detected, the release time is NCONT*NSTEP. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: this property is not available. Si475x/5xC-A55, Default is: 0x0402. FM_NB_CIMP_DETCNTR 15 14 13 12 11 10 9 8 7 6 5 4 3 NSTEP[7:0] NCONT[7:0] 0x04 0x02 2 1 0 Bit Name Function 15:8 NSTEP[7:0] The continuous impulses counter will be increased by this step size when impulse detected in last 1ms time window. Si475x/5xC-A55, Default is 4. Range is 0 to 255. 7:0 NCONT[7:0] For this given number of continuous impulses detected in every consequent 1ms time window, the detector will assert. Si475x/5xC-A55, Default is 2. Range is 0 to 255. Property 0x2116 FM_NB_CIMP_A2PTH The FM_NB_CIMP_A2PTH property sets the Independent IQ impulse detection threshold for continuous impulse detection. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available. Si475x/5xC-A55, Default: 0x0800. FM_NB_CIMP_HICUT_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RATIO[15:0] 0x0800 Bit Name 15:0 RATIO[15:0] Function Sets the Continuous impulse detector threshold of average to peak ratio. The ratio is RATIO[15:0]/32768, range is 0-1.0. Si475x/5xC-A55, Default is 0x0800. Rev. 0.9 125 AN543 Property 0x2117 FM_NB_CIMP_IMPDET The FM_NB_CIMP_IMPDET property sets the noise blanker impulse detection threshold to replace property 0x2100 and 0x2105 when continuous impulses are detected. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: this property is not available. Si475x/5xC-A55, Default is: 0x400A. FM_NB_CIMP_IMPDET 15 14 13 Bit 12 11 10 9 8 7 6 5 4 3 WEAK[7:0] NORM[7:0] 0x40 0x0A 2 1 0 Name Function 15:8 WEAK[7:0] Sets the MPX noise blanker threshold at weak signal case replacing property 0x2105 when continuous impulses are detected. the scale of this field is property 0x2105>>8. Si475x/5xC-A55, Default is 0x40. Range is 0 ~ 255. 7:0 NORM[7:0] Sets the MPX noise blanker threshold at normal signal case replacing property 0x2100 when continuous impulses are detected. Si475x/5xC-A55, Default is 0x0A. Range is 0 ~ 255. Property 0x2118 FM_NB_CIMP_MPX_INTV The FM_NB_CIMP_MPX_INTV property sets the MPX noise blanker interval when continuous impulses are detected replacing property 0x2101. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available Si475x/5xC-A55, Default: 0x0A0A Unit: ms FM_NB_CIMP_HICUT_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 INTV[15:0] 0x0A0A 126 Bit Name Function 15:0 INTV[15:0] MPX blanker interval when continuous impulses are detected, high Byte is for strong signal case, low Byte is for weak signal case. Si475x/5xC-A55, Default is 0x0A0A, Range is 0 ~ 32767. Rev. 0.9 AN543 Property 0x2200 FM_CHBW_SQ_MIN_MAX The FM_CHBW_SQ_MIN_MAX property sets the maximum and minimum Channel Filter Bandwidth in kHz based on RSSI/STRONGDEV (for Si475x-A20 and later) or RSSI/SNR (for Si475x-A10), as selected with through property 0x1306, FM_ACF_CONTROL. For Si475x-A20 and later, this engine is only enabled when RSSI is below the FM_CHBW_WEAKSIG_THR (property 0x220F). To force a given Channel Filter Bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Notes: 1. The Si4750/51/52/53 do not support dynamic bandwidth control, hence MIN[7:0] = MAX[7:0]. The minimum of MAX[7:0] of properties 0x2200, 0x2205, and 0x220A determines the Channel Filter Bandwidth. Default for Si4750/51/52/53-A10 is 110 kHz; default for Si4750/51/52/53-A20/A30 is 150 kHz. 2. RSSI/SNR can be used to control this engine for Si475x-A10. RSSI/STRONGDEV can be used to control this engine for Si475x-A20 and later. Si4754/55/56/57 Default: 0x9637 Si4750/51/52/53 Default: 0x6E6E Units: kHz FM_CHBW_SQ_MIN_MAX 15 Bit 15:8 7:0 14 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x96 0x37 Name 2 1 0 Function MAX [7:0] Sets the maximum Channel Filter Bandwidth in kHz. Si4754/55/56/57 default is 150 kHz. Si4750/51/52/53 default is 110 kHz. Range is 1-150 kHz. MIN [7:0] Sets the minimum Channel Filter Bandwidth in kHz. Si4754/55/56/57 default is 55 kHz. Si4750/51/52/53 default is 110 kHz. Range is 1-150 kHz. Rev. 0.9 127 AN543 Property 0x2201 FM_CHBW_SQ_HIGH_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_SQ_HIGH_THRESHOLD property sets the threshold for maximum Channel Filter Bandwidth based on RSSI/STRONGDEV (for Si475x-A20 and later) or RSSI/SNR (for Si475x-A10), as selected with through property 0x1306, FM_ACF_CONTROL. For Si475x-A20 and later, this engine is only enabled when RSSI is below the FM_CHBW_WEAKSIG_THR (property 0x220F). If the instantaneous RSQ value is greater than or equal to the programmed RSSI high threshold, then the Channel Filter Bandwidth will be set to the maximum value programmed through Property 0x2200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: RSSI/SNR can be used to control this engine for Si475x-A10. RSSI/STRONGDEV can be used to control this engine for Si475x-A20 and later. Default: 12 Units: dB for RSSI/SNR metrics, kHz for STRONGDEV metric FM_CHBW_SQ_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 SQMAX[15:0] 0x000C Bit 15:0 128 Name SQMAX[15:0] Function Sets the RSSI threshold for maximum Channel Filter Bandwidth. Default is 12 dBV Range is -128 to 127 dBV for Si475x-A20 and later; Range is 0-127 for Si475x-A10. Rev. 0.9 0 AN543 Property 0x2202 FM_CHBW_SQ_LOW_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_SQ_LOW_THRESHOLD property sets the threshold for minimum Filter Channel Bandwidth based on RSSI/STRONGDEV (for Si475x-A20 and later) or RSSI/SNR (for Si475x-A10), as selected with through property 0x1306, FM_ACF_CONTROL. For Si475x-A20 and later, this engine is only enabled when RSSI is below the FM_CHBW_WEAKSIG_THR (property 0x220F). If the instantaneous RSQ value is less than or equal to the programmed RSSI low threshold, then the Channel Filter Bandwidth will be set to the minimum value programmed through Property 0x2200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: RSSI/SNR can be used to control this engine for Si475x-A10. RSSI/STRONGDEV can be used to control this engine for Si475x-A20 and later. Si475x-A40 and earlier, Default: -4 Si475x/5xC-A55, Default: 2 Units: dB for RSSI/SNR metrics, kHz for STRONGDEV metric FM_CHBW_SQ_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SQMIN[15:0] 0x0002 Bit 15:0 Name Function SQMIN[15:0] Sets the RSSI threshold for minimum Channel Filter Bandwidth. Si475x/5xC-A55, Default is 2 dBV Range is -127 to 128 dBV for Si475x-A20 and later. Range is 0-127 for Si475x-A10. Rev. 0.9 129 AN543 Property 0x2203 FM_CHBW_SQ_WIDENING_TIME (Si4754/55/56/57 Only) The FM_CHBW_SQ_WIDENING_TIME property sets the Channel Filter Bandwidth widening time based on RSSI/ STRONGDEV (for Si475x-A20 and later) or RSSI/SNR (for Si475x-A10), as selected with through property 0x1306, FM_ACF_CONTROL. For Si475x-A20 and later, this engine is only enabled when RSSI is below the FM_CHBW_WEAKSIG_THR (property 0x220F). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: RSSI/SNR can be used to control this engine for Si475x-A10. RSSI/STRONGDEV can be used to control this engine for Si475x-A20 and later. Default: 16 Si475x-A10, Units: ms Si475x-A20, Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms FM_CHBW_SQ_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0010 Bit 15:0 130 Name WIDENING_TIME[15:0] Function Sets the RSSI based Channel Filter Bandwidth widening time. Default is 16. Range is 1-32767. Rev. 0.9 AN543 Property 0x2204 FM_CHBW_SQ_NARROWING_TIME (Si4754/55/56/57 Only) The FM_CHBW_SQ_NARROWING_TIME property sets the Channel Filter Bandwidth narrowing time based on RSSI/STRONGDEV (for Si475x-A20 and later) or RSSI/SNR (for Si475x-A10), as selected with through property 0x1306, FM_ACF_CONTROL. For Si475x-A20 and later, this engine is only enabled when RSSI is below the FM_CHBW_WEAKSIG_THR (property 0x220F). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: RSSI/SNR can be used to control this engine for Si475x-A10. RSSI/STRONGDEV can be used to control this engine for Si475x-A20 and later. Default: 2048 Si475x-A10, Units: ms Si475x-A20, Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms FM_CHBW_SQ_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0800 Bit 15:0 Name NARROWING_TIME[15:0] Function Sets the RSSI based Channel Filter Bandwidth narrowing time. Default is 2048. Range is 1-32767. Rev. 0.9 131 AN543 Property 0x2205 FM_CHBW_ASSI_MIN_MAX The FM_CHBW_ASSI_MIN_MAX property sets the maximum and minimum Channel Filter Bandwidth in kHz based on delta (HASSI,LASSI). To force a given Channel Filter Bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Notes: 1. The Si4750/51/52/53 do not support dynamic bandwidth control, hence MIN[7:0] = MAX[7:0]. The minimum of MAX[7:0] of properties 0x2200, 0x2205, and 0x220A determines the Channel Filter Bandwidth. Default for Si4750/51/52/53 is 150 kHz. 2. Delta (HASSI,LASSI) is the absolute difference between HASSI and LASSI. In Si475x-A30 and later, at least one of HASSI or LASSI must be greater than -15 dB in order for these settings to be observed. Otherwise, the adjacent channels are considered empty, and the Filter Channel Bandwidth will not be limited based on ASSI. Si4754/55/56/57 Default: 0x9623 Si4750/51/52/53 Default: 0x9696 Units: kHz FM_CHBW_ASSI_MIN_MAX 15 Bit 15:8 7:0 132 14 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x96 0x23 Name Function MAX [7:0] Sets the maximum Channel Filter Bandwidth in kHz. Si4754/55/56/57 default is 150 kHz. Si4750/51/52/53 default is 150 kHz. Range is 1-150 kHz. MIN [7:0] Sets the minimum Channel Filter Bandwidth in kHz. Si4754/55/56/57 default is 35 kHz. Si4750/51/52/53 default is 150 kHz. Range is 1-150 kHz. Rev. 0.9 2 1 0 AN543 Property 0x2206 FM_CHBW_ASSI_LOW_THRESHOLD (Si4754/55/56/57 Only) Sets the 100 kHz blocker delta (difference between HASSI and LASSI) threshold for maximum Channel Filter Bandwidth. If the 100 kHz blocker delta is less than or equal to the programmed ASSI low threshold, then the Channel Filter Bandwidth will be set to the maximum value programmed through Property 0x2205. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Note: Delta (HASSI,LASSI) is the absolute difference between HASSI and LASSI. In Si475x-A30 and later, at least one of HASSI or LASSI must be greater than -15 dB in order for these settings to be observed. Otherwise, the adjacent channels are considered empty, and the Filter Channel Bandwidth will not be limited based on ASSI. Default: 7 Units: dB FM_CHBW_ASSI_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ASSIMIN[15:0] 0x0007 Bit 15:0 Name ASSIMIN[15:0] Function Sets the 100 kHz blocker delta threshold for maximum channel filter bandwidth. Default is 7 dB. Range is -128 to 127 dB. Rev. 0.9 133 AN543 Property 0x2207 FM_CHBW_ASSI_HIGH_THRESHOLD (Si4754/55/56/57 Only) Sets the 100 kHz blocker delta (difference between HASSI and LASSI) threshold for minimum Channel Filter Bandwidth. If the 100 kHz blocker delta is greater than the programmed ASSI high threshold, then the Channel Filter Bandwidth will be set to the minimum value programmed through Property 0x2205. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Note: Delta (HASSI,LASSI) is the absolute difference between HASSI and LASSI. In Si475x-A30 and later, at least one of HASSI or LASSI must be greater than -15 dB in order for these settings to be observed. Otherwise, the adjacent channels are considered empty, and the Filter Channel Bandwidth will not be limited based on ASSI. Default: 20 Units: dB FM_CHBW_ASSI_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ASSIMAX[15:0] 0x0014 Bit 15:0 134 Name ASSIMAX[15:0] Function Sets the 100 kHz blocker delta threshold for minimum channel filter bandwidth. Default is 20 dB. Range is -128 to 127 dB. Rev. 0.9 0 AN543 Property 0x2208 FM_CHBW_ASSI_WIDENING_TIME (Si4754/55/56/57 Only) Sets the Channel Filter Bandwidth widening time based on the 100 kHz blocker delta (difference between HASSI and LASSI). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Si475x-A20 and earlier, Default: 1 Si475x-A30 and later, Default: 3200 Si475x-A10, Units: ms Si475x-A20, Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms FM_CHBW_ASSI_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0C80 Bit 15:0 Name Function Sets the 100 kHz blocker delta based Channel Filter Bandwidth widening time. WIDENING_TIME[15:0] Default is 1 (Si475x-A20 and earlier) or 3200 (Si475x-A30 and later). Range is 1-32767. Rev. 0.9 135 AN543 Property 0x2209 FM_CHBW_ASSI_NARROWING_TIME (Si4754/55/56/57 Only) Sets the Channel Filter Bandwidth narrowing time based on the 100 kHz blocker delta (difference between HASSI and LASSI). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Default: 320 Si475x-A10, Units: ms Si475x-A20, Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms FM_CHBW_ASSI_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0140 Bit 15:0 136 Name NARROWING_TIME[15:0] Function Sets the 100 kHz blocker delta based Channel Filter Bandwidth narrowing time. Default is 320. Range is 1-32767. Rev. 0.9 AN543 Property 0x220A FM_CHBW_ASSI200_MIN_MAX The FM_CHBW_ASSI200_MIN_MAX property sets the maximum and minimum Channel Filter Bandwidth in kHz based on ASSI200. To force a given Channel Filter Bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: The Si4750/51/52/53 do not support dynamic bandwidth control, hence MIN[7:0] = MAX[7:0]. The minimum of MAX[7:0] of properties 0x2200, 0x2205, and 0x220A determines the Channel Filter Bandwidth. Default for Si4750/51/52/53 is 150 kHz. Si4754/55/56/57-A10 Default: 0x9632 Si4754/55/56/57-A20/A30/A40, Default: 0x9650 Si4750/51/52/53 Default: 0x9696 Si475x/5xC-A55, Default: 0x964B Units: kHz FM_CHBW_ASSI200_MIN_MAX 15 14 Bit 15:8 7:0 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x96 0x4B 2 1 0 Name Function MAX[7:0] Sets the maximum Channel Filter Bandwidth in kHz. Si4754/ 55/56/57 default is 150 kHz. Si4750/51/52/53 default is 150 kHz. Si475x/5xC-A55, Default is 150 kHz Range is 1-150 kHz. MIN[7:0] Sets the minimum Channel Filter Bandwidth in kHz. Si4754/55/56/57-A20/A30/A40, Default is 80 kHz. Si4754/55/56/57-A10, Default is 55 kHz. Si4750/51/52/53, Default is 150 kHz. Si475x/5xC-A55, Default is 75 kHz Range is 1-150 kHz Rev. 0.9 137 AN543 Property 0x220B FM_CHBW_ASSI200_LOW_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_ASSI200_LOW_THRESHOLD property sets the ASSI200 threshold for maximum Channel Filter Bandwidth. If the ASSI200 is less than or equal to the programmed ASSI200 low threshold, then the Channel Filter Bandwidth will be set to the maximum value programmed through Property 0x220A. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Si475x-A40 and earlier, Default: -10 Si475x/5xC-A55, Default: 0 Units: dB relative to desired channel RSSI FM_CHBW_ASSI200_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ASSI200MIN[15:0] 0x0000 Bit 15:0 Name Function ASSI200MIN[15:0] Sets the 200 kHz blocker strength threshold for maximum Channel Filter Bandwidth. Si475x/5xC-A55, Default is 0 dB (relative to desired channel RSSI) Range is -128 to 127 dBr. Property 0x220C FM_CHBW_ASSI200_HIGH_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_ASSI200_HIGH_THRESHOLD property sets the ASSI200 threshold for minimum Channel Filter Bandwidth. If the ASSI200 is greater than the programmed ASSI200 high threshold, then the Channel Filter Bandwidth will be set to the minimum value programmed through Property 0x220A. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Default: 10 Units: dB relative to desired channel RSSI FM_CHBW_ASSI200_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ASSI200MAX[15:0] 0x000A Bit 15:0 138 Name ASSI200MAX[15:0] Function Sets the 200 kHz blocker strength threshold for maximum Channel Filter Bandwidth. Default is 10 dB (relative to desired channel RSSI) Range is -128 to 127 dBr. Rev. 0.9 AN543 Property 0x220D FM_CHBW_ASSI200_WIDENING_TIME (Si4754/55/56/57 Only) The FM_CHBW_ASSI200_WIDENING_TIME property sets the Channel Filter Bandwidth widening time based on the ASSI200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Si475x-A20 and before, Default: 1 Si475x-A30 and A40: Default: 3200 Si475x/5xC-A55, Default: 4000 Si475x-A10, Units: ms Si475x-A20, Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms FM_CHBW_ASSI200_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0FA0 Bit 15:0 Name WIDENING_TIME[15:0] Function Sets the 200 kHz blocker strength based channel filter bandwidth widening time. Si475x/5xC-A55 Default is 4000. Range is 1-32767. Rev. 0.9 139 AN543 Property 0x220E FM_CHBW_ASSI200_NARROWING_TIME (Si4754/55/56/57 Only) The FM_CHBW_ASSI200_NARROWING_TIME property sets the Channel Filter Bandwidth narrowing time based on the ASSI200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Default: 320 Si475x-A10, Units: ms Si475x-A20, Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms FM_CHBW_ASSI200_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 NARROWING_TIME[15:0] 0x0140 Bit 15:0 140 Name NARROWING_TIME[15:0] Function Sets the 200 kHz blocker strength based Channel Filter Bandwidth narrowing time. Default is 320. Range is 1-32767. Rev. 0.9 0 AN543 Property 0x220F FM_CHBW_WEAKSIG_THR (Si4754/55/56/57 Only) The FM_CHBW_WEAKSIG_THR property sets the RSSI value at which the weak signal Channel Filter Bandwidth engine will engage (LOW) and disengage (HIGH). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10: This property is not available Si475x-A20 and later, Default: 0x100D Units: dBV FM_CHBW_WEAKSIG_THR 15 14 13 12 11 10 9 8 7 6 5 4 3 HIGH[7:0] LOW[7:0] 0x10 0x0D 2 1 0 Bit Name Function 15:8 HIGH[7:0] When RSSI is above this value, the weak signal Channel Filter Bandwidth engine disengages. Default: 0x10. Range: -128-127 dBV 7:0 LOW[7:0] When RSSI is below this value, the weak signal Channel Filter Bandwidth engine engages. Default: 0x0D. Range: -128-127 dBV Rev. 0.9 141 AN543 Property 0x2210 FM_CHBW_BLOCKER_THR The FM_CHBW_BLOCKER_THR property sets the ASSI200 value at which the ASSI200DEV channel filter bandwidth engine will engage (HIGH) and disengage (LOW). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 and earlier: This property is not available. Si475x-A20: This feature is not available. Do not write to this property. Si475x-A30 and later, Default: 0x140A Units: dB FM_CHBW_BLOCKER_THR 15 142 14 13 12 11 10 9 8 7 6 5 4 3 HIGH[7:0] LOW[7:0] 0x14 0x0A 2 1 0 Bit Name Function 15:8 HIGH[7:0] When ASSI200 is above this value, the ASSI200DEV channel filter bandwidth engine engages. Default is 20 dB. Range is -128 to 127 dB. 7:0 LOW[7:0] When ASSI200 is below this value, the ASSI200DEV channel filter bandwidth engine disengages. Default is 10 dB. Range is -128 to 127 dB. Rev. 0.9 AN543 Property 0x2214 FM_CHBW_ASSI_B_CONTROL The FM_CHBW_ASSI_B_CONTROL property selects the behavior of ASSI_B (max ASSI) channel filter bandwidth engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30, Default: 0 Si475x-A40 and later, Default: 0x2000 Units: dB FM_CHBW_ASSI_B_CONTROL 15 14 13 12 11 10 6 5 4 3 2 1 0 0x00 ASSI_B_MODE 0x00 10 0x00 0 15:10 Reserved 0 7 FREQOFF_CHBW_MODE[1:0] Name 7:1 8 0x00 Bit 9:8 9 Function Always write to 0. (Available in Si4754/55/56/57-A40 only.) Configures the behavior of Channel Filter Bandwidth based on frequency offset/200kHz blocker deviation. Default:0x2 FREQOFF_CHBW_MODE[1:0] 0 = Use ASSI200DEV to control BW. 1 = Use post-channel filter carrier frequency offset to control BW. 2 = Use the average of pre-channel filter, pre-equalizer and post-equalizer frequency offset to control BW. (For Si475x-A30 and earlier, always write to 0.) Reserved ASSI_B_MODE Always write to 0. Selects the behavior of ASSI_B (max ASSI) channel filter bandwidth engine. Default is 0. 0 = Only engage when blockers are detected at both HASSI and LASSI through beat_detector. 1 = Always engage. Rev. 0.9 143 AN543 Property 0x2215 FM_CHBW_STRONGDEV_MIN_MAX The FM_CHBW_STRONGDEV_MIN_MAX property sets the maximum and minimum Channel Filter Bandwidth in kHz based on STRONGDEV. To force a given Channel Filter Bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: The Si4750/51/52/53 do not support dynamic bandwidth control; hence, MIN[7:0] = MAX[7:0]. The minimum of MAX[7:0] of properties 0x2200, 0x2205, and 0x220A determines the Channel Filter Bandwidth. Default for Si4750/51/52/53-A20/ A30 is 150 kHz. Si475x-A10: This property is not available Si4754/55/56/57-A40 and before Default: 0x9680 Si4750/51/52/53-A40 and before, Default: 0x9696 Si475x/5xC-A55, Default: 0x9664 Units: kHz FM_CHBW_STRONGDEV_MIN_MAX 15 14 Bit 15:8 7:0 144 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x96 0x64 Name 2 1 Function MAX[7:0] Sets the maximum Channel Filter Bandwidth in kHz. Si4754/55/56/57, Default is 150 kHz. Si4750/51/52/53, Default is 150 kHz. Si475x/5xC-A55, Default is 150 kHz Range is 1-150. MIN[7:0] Sets the maximum Channel Filter Bandwidth in kHz. Si4754/55/56/57, Default is 128 kHz. Si4750/51/52/53, Default is 150 kHz. Range is 1-150. Rev. 0.9 0 AN543 Property 0x2216 FM_CHBW_STRONGDEV_LOW_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_STRONGDEV_LOW_THRESHOLD property sets the STRONGDEV threshold for minimum Channel Filter Bandwidth. If the STRONGDEV is less than or equal to the programmed STRONGDEV low threshold, then the Channel Filter Bandwidth will be set to the minimum value programmed through Property 0x2215. The value used here is the result of the formula: For mono: programmed value = desired deviation/5.5 kHz (i.e., 8 corresponds to approximately 44 kHz deviation) For stereo: programmed value = desired deviation/2.75 kHz (i.e., 8 corresponds to approximately 22 kHz deviation). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10: This property is not available Si475x-A20 and later, Default: 8 Units: None FM_CHBW_STRONGDEV_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 STRONGDEVMIN[15:0] 0x0008 Bit 15:0 Name Function STRONGDEVMIN [15:0] Sets the STRONGDEV threshold for minimum Channel Filter Bandwidth. Default is 8. Range is 0-127. Rev. 0.9 145 AN543 Property 0x2217 FM_CHBW_STRONGDEV_HIGH_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_STRONGDEV_HIGH_THRESHOLD property sets the STRONGDEV threshold for maximum Channel Filter Bandwidth. If the STRONGDEV is greater than the programmed STRONGDEV high threshold, then the Channel Filter Bandwidth will be set to the maximum value programmed through Property 0x2215. The value used here is the result of the formula: For mono: programmed value = desired deviation/5.5 kHz (i.e., 19 corresponds to approximately 104 kHz deviation) For stereo: programmed value = desired deviation/2.75 kHz (i.e., 19 corresponds to approximately 52 kHz deviation). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10: This property is not available Si475x-A20 and later, Default: 19 Units: None FM_CHBW_STRONGDEV_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 STRONGDEVMIN[15:0] 0x0013 Bit 15:0 146 Name Function STRONGDEVMIN [15:0] Sets the STRONGDEV threshold for maximum Channel Filter Bandwidth. Default is 19. Range is 0-127. Rev. 0.9 AN543 Property 0x2218 FM_CHBW_STRONGDEV_WIDENING_TIME (Si4754/55/56/57 Only) The FM_CHBW_STRONGDEV_WIDENING_TIME property sets the STRONGDEV based Channel Filter Bandwidth widening time. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10: This property is not available Si475x-A20 and later, Default: 4096 Si475x-A20 Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms Units: ms FM_CHBW_STRONGDEV_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x1000 Bit 15:0 Name Function WIDENING_TIME [15:0] Sets the STRONGDEV based Channel Filter Bandwidth widening time. Default is 4096. Range is 1-32767. Rev. 0.9 147 AN543 Property 0x2219 FM_CHBW_STRONGDEV_NARROWING_TIME (Si4754/55/56/57 Only) The FM_CHBW_STRONGDEV_NARROWING_TIME property sets the STRONGDEV based Channel Filter Bandwidth narrowing time. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10: This property is not available Si475x-A20 and later, Default: 512 Si475x-A20, Units: 0.2 ms Si475x-A30 and later, Units: 0.4 ms FM_CHBW_STRONGDEV_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0200 Bit 15:0 148 Name Function NARROWING_TIME[15:0] Sets the STRONGDEV based Channel Filter Bandwidth narrowing time. Default is 512. Range is 1-32767. Rev. 0.9 AN543 Property 0x221A FM_CHBW_ASSI200DEV_MIN_MAX The FM_CHBW_ASSI200DEV_MIN_MAX property sets the maximum and minimum channel filter bandwidth in kHz based on ASSI200DEV. To force a given Channel Filter Bandwidth, set the min and max to the same value. This engine is only enabled when ASSI200 is above the FM_CHBW_BLOCKER_THR. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: The Si4750/51/52/53 do not support dynamic bandwidth control, hence MIN[7:0] = MAX[7:0]. Default for Si4750/51/52/ 53-A10 is 110 kHz. The default for Si4750/51/52/53-A30 is 150 kHz. Si475x-A20 and earlier: This property is not available. Si475x-A30, Default: 0x5020 Si475x-A40 and later: Default: 0x9646 FM_CHBW_ASSI200DEV_MIN_MAX 15 14 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x96 0x46 Bit Name 15:8 MAX[7:0] Sets the maximum Channel Filter Bandwidth in kHz. Range is 1-150 kHz. 7:0 MIN[7:0] Sets the minimum Channel Filter Bandwidth in kHz. Range is 1-150 kHz. 2 1 0 Function Rev. 0.9 149 AN543 Property 0x221B FM_CHBW_ASSI200DEV_LOW_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_ASSI200DEV_LOW_THERSHOLD property sets the ASSI200DEV threshold for maximum Channel Filter Bandwidth. This engine is only enabled when ASSI200DEV is above the FM_CHBW_BLOCKER_THR. If the ASSI200DEV is less than or equal to the programmed ASSI200DEV low threshold then the Channel Filter Bandwidth will be set to maximum value programmed through Property 0x221A. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 50 FM_CHBW_ASSI200DEV_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ASSI200DEVMAX[15:0] 0x0032 Bit 15:0 150 Name Function Sets the ASSI200DEV threshold for maximum Channel Filter Bandwidth. The minimum such deviation is equal to ASSI200DEVMAX*1.5 kHz minus ASSI200DEVMAX[15:0] 12 kHz. Default is 50. Range is 0-127. Rev. 0.9 0 AN543 Property 0x221C FM_CHBW_ASSI200DEV_HIGH_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_ASSI200DEV_HIGH_THERSHOLD property sets the ASSI200DEV threshold for minimum Channel Filter Bandwidth. This engine is only enabled when ASSI200DEV is above the FM_CHBW_BLOCKER_THR. If the ASSI200DEV is greater than the programmed ASSI200DEV high threshold then the Channel Filter Bandwidth will be set to minimum value programmed through Property 0x221A. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 90 FM_CHBW_ASSI200DEV_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ASSI200DEVMIN[15:0] 0x005A Bit 15:0 Name Function Sets the ASSI200DEV threshold for minimum Channel Filter Bandwidth. The maximum such deviation is equal to ASSI200DEVMIN*1.5 kHz minus ASSI200DEVMIN[15:0] 12 kHz. Default is 90. Range is 0-127. Property 0x221D FM_CHBW_ASSI200DEV_WIDENING_TIME (Si4754/55/56/57 Only) The FM_CHBW_ASSI200DEV_WIDENING_TIME property sets the channel filter bandwidth widening time based on the ASSI200DEVThe CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 2048 Units: 0.4 ms FM_CHBW_ASSI200DEV_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0800 Bit 15:0 Name Function Sets the ASSI200DEV based Channel Filter Bandwidth widening time. WIDENING_TIME[15:0] Default is 2048 (819 ms). Range is 1-32767. Rev. 0.9 151 AN543 Property 0x221E FM_CHBW_ASSI200DEV_NARROWING_TIME (Si4754/55/56/57 Only) The FM_CHBW_ASSI200DEV_WIDENING_TIME property sets the channel filter bandwidth narrowing time based on the ASSI200DEVThe CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 128 Units: 0.4 ms FM_CHBW_ASSI200DEV_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0080 Bit Name Function 15:0 NARROWING_TIME[15:0] Sets the ASSI200DEV based Channel Filter Bandwidth narrowing time. Default is 128 (51 ms). Range is 1-32767. Property 0x221F FM_CHBW_ASSI_B_MIN_MAX The FM_CHBW_ASSI_B_MIN_MAX property sets the maximum and minimum channel filter bandwidth in kHz based on max (HASSI,LASSI). To force a given Channel Filter Bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: The Si4750/51/52/53 do not support dynamic bandwidth control, hence MIN[7:0] = MAX[7:0]. Default for Si4750/51/52/ 53 is 150 kHz. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x9696 FM_CHBW_ASSI_B_MIN_MAX 15 14 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x96 0x96 Bit Name 15:8 MAX[7:0] Sets the maximum Channel Filter Bandwidth in kHz. Default is 150 kHz. Range is 1-150 kHz. 7:0 MIN[7:0] Sets the minimum Channel Filter Bandwidth in kHz. Default is 150 kHz. Range is 1-150 kHz. 152 Function Rev. 0.9 2 1 0 AN543 Property 0x2220 FM_CHBW_ASSI_B_LOW_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_ASSI_B_LOW_THERSHOLD property sets the max (HASSI,LASSI) threshold for maximum Channel Filter Bandwidth. If the max (HASSI,LASSI) is less than or equal to the programmed max (HASSI,LASSI) low threshold then the channel Filter Bandwidth will be set to maximum value programmed through Property 0x221F. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and A40, Default: 0 Si475x/5xC-A55, Default: -5 Units: dB FM_CHBW_ASSI_B_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ASSI_B_MAX[15:0] 0xFFFB Bit 15:0 Name Function ASSI_B_MAX[15:0] Sets the max (HASSI,LASSI) threshold for maximum channel Filter Bandwidth. Si475x/5xC-A55, Default is -5. Range is -128 to 127 dB. Property 0x2221 FM_CHBW_ASSI_B_HIGH_THRESHOLD (Si4754/55/56/57 Only) The FM_CHBW_ASSI_B_HIGH_THERSHOLD property sets the max (HASSI,LASSI) threshold for minimum Channel Filter Bandwidth. If the max (HASSI,LASSI) is greater than the programmed max (HASSI,LASSI) high threshold then the Channel Filter Bandwidth will be set to minimum value programmed through Property 0x221A. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available Si475x-A30 and A40, Default: 0 Si475x/5xC-A55, Default: 5 Units: dB FM_CHBW_ASSI_B_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ASSI_B_MIN[15:0] 0x0005 Bit 15:0 Name Function ASSI_B_MIN[15:0] Sets the max (HASSI,LASSI) threshold for minimum Channel Filter Bandwidth. Si475x/5xC-A55, Default is 5. Range is -128 to 127 dB. Rev. 0.9 153 AN543 Property 0x2222 FM_CHBW_ASSI_B_WIDENING_TIME (Si4754/55/56/57 Only) The FM_CHBW_ASSI_B_WIDENING_TIME property sets the channel filter bandwidth widening time based on the max (HASSI,LASSI). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and A40, Default: 1 Si475x/5xC-A55, Default: 4000 Unit: 0.4 ms FM_CHBW_ASSI_B_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0FA0 Bit Name 15:0 Function WIDENING_TIME[15:0] Sets the max (HASSI,LASSI) based Channel Filter Bandwidth widening time. Si475x/5xC-A55, Default is 4000 (0.4 ms). Range is 1-32767. Property 0x2223 FM_CHBW_ASSI_B_NARROWING_TIME (Si4754/55/56/57 Only) The FM_CHBW_ASSI_B_WIDENING_TIME property sets the channel filter bandwidth narrowing time based on the max (HASSI,LASSI). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and A40, Default: 1 Si475x/5xC-A55, Default: 400 Units: 0.4 ms FM_CHBW_ASSI_B_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0190 Bit 15:0 154 Name Function NARROWING_TIME[15:0] Sets the max (HASSI,LASSI) based Channel Filter Bandwidth narrowing time. Si475x/5xC-A55, Default is 400 (0.4 ms). Range is 1-32767. Rev. 0.9 AN543 Property 0x3105 FM_LOWCUT_MIN_FREQ The FM_LOWCUT_MIN_FREQ property sets the minimum cutoff frequency. The LowCut tracks the HICUT engine; therefore, thresholds are programmed in HICUT threshold properties (0x3600, 0x3608, 0x3610) and the HIBLEND threshold properties (0x3700, 0x3708, 0x3710). Setting the property to 0 disables LowCut. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: This setting requires a re-tune before it can come into effect. Si475x-A20 and earlier: This feature is not available. Do not write to this property. Si475x-A30 and later, Default: 0 Units: Hz FM_LOWCUT_MIN_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 FREQ_MIN[15:0} 0x0000 Bit Name Function 15:0 FREQ_MIN[15:0] Sets the minimum LOW-CUT cutoff frequency in Hz. Default is disabled. Range is 0 (disable) or 8-1000 Hz. 0 = Disabled. Property 0x3106 FM_LOWCUT_MAX_FREQ The FM_LOWCUT_MAX_FREQ property sets the maximum cutoff frequency. The LowCut tracks the HICUT engine, therefore thresholds are programmed in HICUT threshold properties (0x3600, 0x3608, 0x3610) and the HIBLEND threshold properties (0x3700, 0x3708, 0x3710). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This feature is not available. Do not write to this property. Si475x-A30 and later, Default: 0 Units: Hz FM_LOWCUT_MAX_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 FREQ_MAX[15:0] 0x0000 Bit 15:0 Name Function FREQ_MAX[15:0] Sets the maximum LOW-CUT cutoff frequency in Hz. Note that if property 0x3105 (FM_LOWCUT_MIN_FREQ) is non-zero, this property must be set to a value no less than property 0x3105. Default is 0 Hz. Range is 8-1000 Hz. Rev. 0.9 155 AN543 Property 0x3200 FM_POP_NOISE_FADE_HYST (Si4754/55/56/57 Only) The FM_POP_NOISE_FADE_HYST property sets the thresholds for FM pop filter fading hysteresis. The pop noise filter will engage once fade is at least equal to the HIGH setting. Once engaged, the pop filter will remain engaged until the fade becomes as low as the LOW setting. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: Fade is an internal metric, and is not available to the user for inspection. Units are in dB Si475x-A20 and earlier: This feature is not available. Do not write to this property. Si475x-A30 and A40, Default: 0x0A06 Si475x/5xC-A55, Default: 0x0604 FM_POP_NOISE_FADE_HYST 15 14 13 12 11 10 9 8 7 6 5 4 3 HIGH[7:0] LOW[7:0] 0x06 0x04 Bit Name 15:8 HIGH[7:0] 7:0 LOW[7:0] 2 1 0 Function If the fade this greater than this value, the FM pop filter is turned on. Si475x/5xC-A55, Default is 6. Range is -127 to 127. If the fade this less than this value, the FM pop filter is turned off. Si475x/5xC-A55, Default is 4. Range is -127 to 127. Property 0x3207 FM_POP_NOISE_MODE (Si4754/55/56/57 Only) The FM_POP_NOISE_MODE property sets the mitigation mode for the FM POP filter. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0x0001 Si475x/5xC-A55, Default: 0x0002 FM_POP_NOISE_MODE 15 Bit 1:0 156 14 13 12 11 10 9 8 7 5 4 3 2 1 0 0x0000 MODE[1:0] 0x0000 02 Name MODE[1:0] 6 Function Sets the mitigation mode for FM POP filter. Si475x/5xC-A55, Default is 2. 0 = Pop mitigation off. 1 = Pop mitigation at MPX on. 2 = Pop mitigation at MPX on, but MPX RMS level sets the mitigation limit (only applicable to Si475x-A30 and later). Rev. 0.9 AN543 Property 0x3208 FM_POP_NOISE_RSSI_THRESHOLDS (Si4754/55/56/57 Only) The FM_POP_NOISE_RSSI_THERSHOLDS property sets the change in RSSI thresholds for maximum and minimum MPX limiting (set by property 0x3209). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Si475x-A10: This property is not available. Si475x-A20/A30/A40, Default: 0xECE7 Si475x/5xC-A55, Default: 0xFDF9 FM_POP_NOISE_RSSI_THRESHOLDS 15 14 13 12 11 10 9 8 7 6 5 4 3 XMAX[7:0] XMIN[7:0] 0xFD 0xF9 2 1 0 Bit Name Function 15:8 XMAX[7:0] Sets the maximum change in RSSI threshold. If the change in RSSI is above this threshold maximum MPX limiting will be achieved as set by property 0x3209. Range is -127 to 127 (dB). 7:0 XMIN[7:0] Sets the minimum change in RSSI threshold. If the change in RSSI is below this threshold minimum MPX limiting will be achieved as set by property 0x3209. Range is -127 to 127 (dB). Property 0x3209 FM_POP_NOISE_RSSI_MPX_LIMIT (Si4754/55/56/57 Only) The FM_POP_NOISE_RSSI_MPX_LIMIT property sets the minimum and maximum limit for MPX limiter based on change in RSSI. To force a given setting (i.e. either completely on or completely off) set YMIN = YMAX. To disable the MPX limiter based on change in RSSI, set YMIN = YMAX = 127. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Si475x-A10: This property is not available. Si475x-A20/A30/A40, Default: 0x1009 Si475x/5xC-A55, Default: 0x0502 FM_POP_NOISE_RSSI_MPX_LIMIT 15 14 13 12 11 10 9 8 7 6 5 4 3 YMAX[7:0] YMIN[7:0] 0x05 0x02 2 Bit Name 15:8 YMAX[7:0] Sets the upper limit. Si475x/5xC-A55, Default: 0x05. Range 0-127. 7:0 YMIN[7:0] Sets the lower limit. Si475x/5xC-A55, Default: 0x02. Range 0-127. 1 0 Function Rev. 0.9 157 AN543 Property 0x320A FM_POP_NOISE_RSSI_MPX_ATTACK (Si4754/55/56/57 Only) The FM_POP_NOISE_RSSI_MPX_ATTACK property sets the attack rate for MPX pop limiter mitigation. The attack time is in milliseconds. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x/5xC-A55, Default: 0x001E Si475x-A40 and earlier, Default: 0x0001 Si475x-A10: This property is not available. Si475x-A20, Units: 0.05 ms Si475x-A30 and later, Units: 0.4 ms FM_POP_NOISE_RSSI_MPX_ATTACK 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0001E Bit Name 15:0 Function ATTACK[15:0] Sets the attack rate for MPX pop limiter mitigation. Range is 1 -32767. Property 0x320B FM_POP_NOISE_RSSI_MPX_RELEASE (Si4754/55/56/57 Only) The FM_POP_NOISE_RSSI_MPX_RELEASE property sets the release rate for pop limiter mitigation. The release time is in milliseconds. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x/5xC-A55, Default: 3000 Si475x-A40 and earlier, Default: 1 Si475x-A10: This property is not available. Si475x-A20, Units: 0.05 ms FM_POP_NOISE_RSSI_MPX_RELEASE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 RELEASE[15:0] 0x0BB8 Bit 15:0 158 Name Function RELEASE[15:0] Sets the release rate for MPX pop limiter mitigation. Range is 1-32767. Rev. 0.9 1 0 AN543 Property 0x320C FM_POP_NOISE_MPX_USN_THRESHOLDS (Si4754/55/56/57 Only) The FM_POP_NOISE_MPX_USN_THRESHOLDS property sets the ratio of MPX to USN thresholds for maximum and minimum MPX limiting (set by property 0x320D). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Si475x-A10 is not available Si475x-A40 and before, Default: 0x03FE Si475x/5xC-A55, Default: 0x0501 FM_POP_NOISE_MPX_USN_THRESHOLDS 15 14 13 12 11 10 9 8 7 6 5 4 3 XMAX[7:0] XMIN[7:0] 0x05 0x01 2 1 0 Bit Name Function 15:8 XMAX[7:0] Sets the maximum MPX limiting based on ratio of MPX to USN. If the ratio of MPX to USN is above this threshold maximum MPX limiting will be achieved as set by FM_POP_NOISE_MPX_USN_LIMIT. Range is -127 to127. 7:0 XMIN[7:0] Sets the minimum MPX limiting based on ratio of MPX to USN. If the ratio of MPX to USN is below this threshold minimum MPX limiting will be achieved as set by FM_POP_NOISE_MPX_USN_LIMIT. Range is -127 to 127. Property 0x320D FM_POP_NOISE_MPX_USN_LIMITS (Si4754/55/56/57 Only) The FM_POP_NOISE_MPX_USN_LIMIT property sets the maximum and minimum limit for MPX limiter based on ratio of MPX to USN. To force a given setting (i.e. either completely on or completely off) set YMIN = YMAX. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Si475x-A10 is not available Si475x-A40 and before, Default: 0x1009 Si475x/5xC-A55, Default: 0x0502 FM_POP_NOISE_MPX_USN_LIMIT 15 14 13 12 11 10 9 8 7 6 5 4 3 YMAX[7:0] YMIN[7:0] 0x05 0x02 2 Bit Name 15:8 YMAX[7:0] Maximum limiting for MPX_NOISE based limiter. Range is 0-127. 7:0 YMIN[7:0] Minimum limiting for MPX_NOISE based limiter. Range is 0-127. 1 0 Function Rev. 0.9 159 AN543 Property 0x320E FM_POP_NOISE_MPX_USN_ATTACK (Si4754/55/56/57 Only) The FM_POP_NOISE_MPX_USN_ATTACK property sets the attack rate for MPX pop limiter mitigation. The attack time is in milliseconds. Si475x-A10 is not available Si475x-A20/A30/A40, Default: 1 Si475x/5xC-A55, Default: 30 Si475x-A20, Units: 0.05 ms Si475x-A30 and later, Units: 0.4 ms FM_POP_NOISE_MPX_USN_ATTACK 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x001E Bit Name Function 15:0 ATTACK[15:0] Maximum limiting for MPX_NOISE based limiter. Range is 1-32767. Property 0x320F FM_POP_NOISE_MPX_USN_RELEASE (Si4754/55/56/57 Only) The FM_POP_NOISE_MPX_USN_RELEASE property sets the release rate for MPX pop limiter mitigation. The release time is in milliseconds. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 is not available Si475x-A20/A30/A40, Default: 1 Si475x/5xC-A55, Default: 3000 Si475x-A20, Units: 0.05 ms Si475x-A30 and later, Units: 0.4 ms FM_POP_NOISE_MPX_USN_RELEASE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 RELEASE[15:0] 0x0BB8 Bit Name 15:0 RELEASE[15:0] 160 Function Sets release rate for MPX pop limiter mitigation. Range is 1-32767. Rev. 0.9 1 0 AN543 Property 0x3210 FM_POP_NOISE_SCALE The FM_POP_NOISE_SCALE property sets the scale for the FM pop filter. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 127 FM_POP_NOISE_SCALE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SCALE[7:0] 0x00 0x7F Bit Name 15:8 Reserved 7:0 SCALE[7:0] 1 0 Function Always write to 0. Sets the scale for the FM pop filter. This allows users to scale back the pop filter. Default is 127. Range is 0-127, which scales the pop filter from full on (127) to full off (0) Property 0x3400 FM_MULT_EQ_CTL (Si4754/55/56/57 Only) The FM_MULT_EQ_CTL property controls the multipath channel equalizer. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x0601 Si475x/5xC-A55, Default: 0x8001 FM_MULT_EQ_CTL 15 14 13 SOURCE CMA_CTRL_MP 0 NUM_TAPS[4:0] 0x00 MULT_EQ_CTL[1:0] 1 0 0 0x00 0x00 0x1 Bit 15 14 12 11 10 9 8 Name SOURCE CMA_CTRL_MP 7 6 5 4 3 2 1 0 Function (Available in Si475x/5xC-A55 and later only. Otherwise write to 0.) When NUM_TAPS is in auto mode, this sets the metric source to use for determining the number of taps to use. 0 = Determine number of taps from RSSI metric. 1 = Determine number of taps from SNR metric. Sets the CMA_CTRL_MP value between a less aggressive setting and a more aggressive setting. 0 = less aggressive setting. 1 = more aggressive setting. Rev. 0.9 161 AN543 Bit Name 13 Reserved 12:8 NUM_TAPS[4:0] 7:2 Reserved 1:0 162 Function Always write to 0. (Only applicable to Si475x/5xC-A55 and later, it is fixed at 6 taps for Si4754/55/ 56/57-A30 and A40). Sets the number of taps for the CHEQ. Default is Automatically control taps. 0 = Automatically changes the number of taps from 1 to 20 based on signal quality metrics. 1 = 1 taps. 2 = 2 taps. 3 = 3 taps. 4 = 4 taps. 5 = 5 taps. 6 = 6 taps. 7 = 7 taps. 8 = 8 taps. 9 = 9 taps. 10 = 10 taps. 12 = 12 taps. 14 = 14 taps. 16 = 16 taps. 18 = 18 taps. 20 = 20 taps. Always write to 0. Controls the multipath channel equalizer. Default is 1. MULT_EQ_CTL[1:0] 0 = Channel equalizer OFF. 1 = Channel equalizer ON. Rev. 0.9 AN543 Property 0x3401 FM_MULT_EQ_NOISE_DISABLE (Si4754/55/56/57 Only) The FM_MULT_EQ_NOISE_DISABLE property sets the RSSI threshold below which the channel equalizer will use noise measurements to enable/disable the channel equalizer. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available Si475x-A30, Default: 0xFC81 Si475x-A40 and later, Default: 0xFCFA FM_MULT_EQ_NOISE_DISABLE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 MULT_EQ_ON_LEVEL[7:0] MULT_EQ_OFF_LEVEL[7:0] 0xFC 0xFA 0 Bit Name Function 15:8 MULT_EQ_ON_LEVEL[7:0] 7:0 RSSI level below which noise measurements will be used to enable/disMULT_EQ_OFF_LEVEL[7:0] able the equalizer. Set to -127 (0x81) to disable. Range is -127 to 127. RSSI level above which noise measurements will not be used to enable/ disable the equalizer. Range is -127 to 127. Property 0x3402 FM_MULT_EQ_CTL_STEP (Si4754/55/56/57 Only) The FM_MULT_EQ_CTL_STEP property controls the multipath channel equalizer tap updating step. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available Si475x-A30 and later, Default: 0x0000 FM_MULT_EQ_CTL_STEP 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 STEP[15:0] 0x0000 Bit Name 15:0 STEP[15:0] Function Sets the multipath channel equalizer tap updating step. The number should always be a positive number. Higher number indicates higher updating step. Default is 0 (on chip control). Rev. 0.9 163 AN543 Property 0x3409 FM_EQ_CTL_AUTOTAP The FM_EQ_CTL_AUTOTAP property sets the SNR or RSSI trigger and end threshold for CHEQ auto tap control, it only works when NUM_TAPS in property 0x3400 is set to be 0(automatic EQ taps). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available. Si475x/5xC-A55, Default: 0x03FB FM_EQ_CTL_AUTOTAP 15 Bit 15:8 7:0 164 14 13 12 11 10 9 8 7 6 5 4 3 TRIGTHR[7:0] ENDTHR[7:0] 0x03 0xFB 2 1 0 Name Function TRIGTHR[7:0] Sets the SNR or RSSI threshold that CHEQ will automatically begin to reduce its taps, there should be 0 < (TRIGTHR - ENDTHR) < 32, the range is -127 to 127. Default is: 3 ENDTHR[7:0] Sets the SNR or RSSI threshold that CHEQ will finally reduce to its minimum tap, there should be 0 < (TRIGTHR - ENDTHR) < 32, the range is -127 to 127. Default is: -5 Rev. 0.9 AN543 Property 0x3500 FM_BLEND_RSSI_THRESHOLDS The FM_BLEND_RSSI_THRESHOLDS property sets the limits for the RSSI input metric on the stereo blend mitigation engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x3719 Units: dBV FM_BLEND_RSSI_THRESHOLDS 15 14 13 12 11 10 9 8 7 6 5 4 3 RSSIMAX[7:0] RSSIMIN[7:0] 0x37 0x19 2 1 0 Bit Name Function 15:8 RSSIMAX[7:0] Sets the RSSI Max threshold. If RSSI is above this threshold, maximum stereo separation will be achieved as set by property 0x3501. Default is 55 dBV. Range is -20 to 120 dBV. 7:0 RSSIMIN[7:0] Sets the RSSI Min threshold. If RSSI is below this threshold, minimum stereo separation will be achieved as set by property 0x3501. Default is 25 dBV. Range is -20 to 120 dBV. Property 0x3501 FM_BLEND_RSSI_STEREO_SEP The FM_BLEND_RSSI_STEREO_SEP property sets the maximum and minimum stereo separation based on RSSI (set by Property 0x3500) on the blend engine. You can force a constant stereo separation value by setting ST_SEPMAX and ST_SEPMIN to the same value. To disable the stereo blend based on RSSI, set ST_SEPMAX = ST_SEPMIN = 64. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x2D00 Units: dB FM_BLEND_RSSI_STEREO_SEP 15 14 13 12 11 10 9 8 7 6 5 4 3 ST_SEPMAX[7:0] ST_SEPMIN[7:0] 0x2D 0x00 2 1 0 Bit Name Function 15:8 ST_SEPMAX[7:0] Sets the maximum stereo separation. Default is 45 dB. Range is 0-64 dB. 7:0 ST_SEPMIN[7:0] Sets the minimum stereo separation. Default is 0 dB. Range is 0-64 dB. Rev. 0.9 165 AN543 Property 0x3502 FM_BLEND_RSSI_ATTACK_TIME The FM_BLEND_RSSI_ATTACK_TIME property sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 16 Units: ms FM_BLEND_RSSI_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0010 Bit Name Function 15:0 ATTACK[15:0] Sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on RSSI. Default is 16 ms. Range is 1-32767 ms. Property 0x3503 FM_BLEND_RSSI_RELEASE_TIME The FM_BLEND_RSSI_RELEASE_TIME property sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4000 Units: ms FM_BLEND_RSSI_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 166 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on RSSI. Default is 4000 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x3508 FM_BLEND_MULTIPATH_THRESHOLDS The FM_BLEND_MULTIPATH_THRESHOLDS property sets the Multipath thresholds for maximum and minimum stereo separation (set by Property 0x3509) on the blend engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0x1E3C Si475x/5xC-A55, Default: 0x0A14 FM_BLEND_MULTIPATH_THRESHOLDS 15 14 Bit 15:8 7:0 13 12 11 10 9 8 7 6 5 4 3 MULTMIN[7:0] MULTMAX[7:0] 0x0A 0x14 2 1 0 Name Function MULTMIN[7:0] Sets the Multipath Min threshold. If Multipath is below this threshold, maximum stereo separation will be achieved as set by property 0x3509. Si475x/5xC-A55, Default is 10. Si475x-A10 and earlier, and Si475x-A30 and later: Range is 0-127 Si475x-A20: Range: 0-100. MULTMAX[7:0] Sets the Multipath Max threshold. If Multipath is above this threshold, minimum stereo separation will be achieved as set by property 0x3509. Si475x/5xC-A55, Default is 20. Si475x-A10 and earlier, and Si475x-A30 and later: Range is 0-127 Si475xA20: Range: 0-100 Rev. 0.9 167 AN543 Property 0x3509 FM_BLEND_MULTIPATH_STEREO_SEP The FM_BLEND_MULTIPATH_STEREO_SEP property sets the maximum and minimum stereo separation based on Multipath (set by Property 0x3508) on the blend engine. You can force a constant stereo separation value by setting ST_SEPMAX and ST_SEPMIN to the same value. To disable the fast stereo blend based on Multipath, set ST_SEPMAX = ST_SEPMIN = 64. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x2D00 Units: dB FM_BLEND_MULTIPATH_STEREO_SEP 15 14 13 12 11 10 9 8 7 6 5 4 3 ST_SEPMAX[7:0] ST_SEPMIN[7:0] 0x2D 0x00 2 1 0 Bit Name Function 15:8 ST_SEPMAX[7:0] Sets the maximum stereo separation. Default is 45 dB. Range is 0-64 dB. 7:0 ST_SEPMIN[7:0] Sets the minimum stereo separation. Default is 0 dB. Range is 0-64 dB. Property 0x350A FM_BLEND_MULTIPATH_ATTACK_TIME The FM_BLEND_MULTIPATH_ATTACK_TIME property sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on Multipath. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 16 Units: ms FM_BLEND_MULTIPATH_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ATTACK[15:0] 0x0010 168 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on Multipath. Default is 16 ms. Range is 1-32767 ms. Rev. 0.9 0 AN543 Property 0x350B FM_BLEND_MULTIPATH_RELEASE_TIME The FM_BLEND_MULTIPATH_RELEASE_TIME property sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4000 Units: ms FM_BLEND_MULTIPATH_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on Multipath. Default is 4000 ms. Range is 1-32767 ms. Property 0x3510 FM_BLEND_USN_THRESHOLDS The FM_BLEND_USN_THRESHOLDS property sets the USN thresholds for maximum and minimum stereo separation (set by Property 0x3511) on the blend engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x341B Units: -dBFS FM_BLEND_USN_THRESHOLDS 15 14 13 12 11 10 9 8 7 6 5 4 3 USNMIN[7:0] USNMAX[7:0] 0x34 0x1B 2 1 0 Bit Name Function 15:8 USNMIN[7:0] Sets the USN Min threshold. If USN is below this threshold, maximum stereo separation will be achieved as set by property 0x3511. Default is -52 dBFS. Range is 0-127 -dBFS. USNMAX[7:0] Sets the USN Max threshold. If USN is above this threshold, minimum stereo separation will be achieved as set by property 0x3511. Default is -27 dBFS. Range is 0-127 -dBFS. 7:0 Rev. 0.9 169 AN543 Property 0x3511 FM_BLEND_USN_STEREO_SEP The FM_BLEND_USN_STEREO_SEP property sets the maximum and minimum stereo separation based on USN (set by Property 0x3510) on the blend engine. You can force a constant stereo separation value by setting ST_SEPMAX and ST_SEPMIN to the same value. To disable the stereo blend based on USN, set ST_SEPMAX = ST_SEPMIN = 64. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x2D00 Units: dB FM_BLEND_USN_STEREO_SEP 15 14 13 12 11 10 9 8 7 6 5 4 3 ST_SEPMAX[7:0] ST_SEPMIN[7:0] 0x2D 0x00 2 1 0 Bit Name Function 15:8 ST_SEPMAX[7:0] Sets the maximum stereo separation. Default is 45 dB. Range is 0-100 dB. 7:0 ST_SEPMIN[7:0] Sets the minimum stereo separation. Default is 0 dB. Range is 0-100 dB. Property 0x3512 FM_BLEND_USN_ATTACK_TIME The FM_BLEND_USN_ATTACK_TIME property sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 16 Units: ms FM_BLEND_USN_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ATTACK[15:0] 0x0010 170 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on USN. Default is 16 ms. Range is 1-32767 ms. Rev. 0.9 0 AN543 Property 0x3513 FM_BLEND_USN_RELEASE_TIME The FM_BLEND_USN_RELEASE_TIME property sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4000 Units: ms FM_BLEND_USN_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on USN. Default is 4000 ms. Range is 1-32767 ms. Property 0x3518 FM_BLEND_CHBW_LIMITS (Si4754/55/56/57 Only) The FM_BLEND_CHBW_LIMITS property sets the limits for the CHBW input metric on the stereo blend mitigation engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x0000 Units: 100 Hz FM_BLEND_CHBW_LIMITS 15 14 13 12 11 10 9 8 7 6 5 4 3 CHBWMAX[7:0] CHBWMIN[7:0] 0x00 0x00 2 1 0 Bit Name Function 15:8 CHBWMAX[7:0] Sets the value of the channel bandwidth that causes maximum stereo separation. Default is 0 kHz. Range is 0-15 kHz. 7:0 CHBWMIN[7:0] Sets the value of the channel bandwidth that causes minimum stereo separation. Default is 0 kHz. Range is 0-15 kHz. Rev. 0.9 171 AN543 Property 0x3519 FM_BLEND_CHBW_STEREO_SEP (Si4754/55/56/57 Only) The FM_BLEND_CHBW_STEREO_SEP property sets the limits for the stereo separation when driven by CHBW on the stereo blend mitigation engine. To force a given setting (either completely on or completely off) set ST_SEPMIN = ST_SEPMAX. To disable the stereo blend based on CHBW, set ST_SEPMIN = ST_SEPMAX = 64 (0x40). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x2D2D Units: dB FM_BLEND_CHBW_STEREO_SEP 15 14 13 12 11 10 9 8 7 6 5 4 3 ST_SEPMAX[7:0] ST_SEPMIN[7:0] 0x2D 0x2D 2 1 0 Bit Name Function 15:8 ST_SEPMAX[7:0] Sets the maximum stereo separation for channel bandwidth based stereo blend. Default is 45 dB. Range is 0-64 dB. 7:0 ST_SEPMIN[7:0] Sets the minimum stereo separation for channel bandwidth based stereo blend. Default is 45 dB. Range is 0-64 dB. Property 0x351A FM_BLEND_CHBW_ATTACK_TIME The FM_BLEND_CHBW_ATTACK_TIME property sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on channel bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 1 Units: ms FM_BLEND_CHBW_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ATTACK[15:0] 0x0001 172 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the stereo blend mitigation engine decreases the stereo separation based on channel bandwidth. Default is 1 ms. Range is 1-32767 ms. Rev. 0.9 0 AN543 Property 0x351B FM_BLEND_CHBW_RELEASE_TIME The FM_BLEND_CHBW_RELEASE_TIME property sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on channel bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 1 Units: ms FM_BLEND_CHBW_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0001 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the stereo blend mitigation engine increases the stereo separation based on channel bandwidth. Default is 1 ms. Range is 1-32767 ms. Property 0x3600 FM_HICUT_RSSI_THRESHOLDS The FM_HICUT_RSSI_THRESHOLDS property sets the RSSI thresholds for HICUT to begin band limiting and reach maximum band limiting on L+R channel based on max and min cutoff frequency (set by Property 0x3601) on the HICUT engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x230F Units: dBV FM_HICUT_RSSI_THRESHOLDS 15 14 13 12 11 10 9 8 7 6 5 4 3 RSSIMAX[7:0] RSSIMIN[7:0] 0x23 0x0F 2 1 0 Bit Name Function 15:8 RSSIMAX[7:0] Sets the RSSI level at which HICUT begins to band limit on the L+R channel based on cutoff frequency set by property 0x3601. Default is 35 dBV. Range is -20-120 dBV. 7:0 RSSIMIN[7:0] Sets the RSSI level at which HICUT reaches maximum band limiting on the L+R channel based on cutoff frequency set by property 0x3601. Default is 15 dBV. Range is -20-120 dBV. Rev. 0.9 173 AN543 Property 0x3601 FM_HICUT_RSSI_CUTOFF_FREQ The FM_HICUT_RSSI_CUTOFF_FREQ property sets the maximum and minimum cutoff frequencies based on RSSI (set by Property 0x3600) on the HICUT engine. You can force a constant cutoff frequency value by setting FREQ_MAX and FREQ_MIN to the same value. To disable the HICUT based on RSSI, set FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0xB428 Si475x/5xC-A55, Default: 0xB419 Units: 100 Hz FM_HICUT_RSSI_CUTOFF_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0xB4 0x19 2 1 0 Bit Name Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0-18 kHz. 7:0 FREQ_MIN[7:0] Sets the minimum stereo separation. Range is 0-18 kHz. Si475x/5xC-A55, Default is 2.5 kHz. Property 0x3602 FM_HICUT_RSSI_ATTACK_TIME The FM_HICUT_RSSI_ATTACK_TIME property sets the transition time for which the HICUT mitigation engine lowers the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 16 Si475x/5xC-A55, Default: 100 Units: ms FM_HICUT_RSSI_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0064 174 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the HICUT mitigation engine lowers the cutoff frequency based on RSSI. Si475x/5xC-A55, Default is 100 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x3603 FM_HICUT_RSSI_RELEASE_TIME The FM_HICUT_RSSI_RELEASE_TIME property sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4000 Units: ms FM_HICUT_RSSI_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on RSSI. Default is 4000 ms. Range is 1-32767 ms. Property 0x3608 FM_HICUT_MULTIPATH_THRESHOLDS The FM_HICUT_MULTIPATH_THRESHOLDS property sets the Multipath thresholds for HICUT to begin band limiting and reach maximum band limiting on L+R channel based on max and min cutoff frequencies (set by Property 0x3609) on the HICUT engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0x3250 Si475x/5xC-A55, Default: 0x0A14 Unit: % FM_HICUT_MULTIPATH_THRESHOLDS 15 14 Bit 13 12 11 10 9 8 7 6 5 4 3 MULTMIN[7:0] MULTMAX[7:0] 0x0A 0x14 2 1 0 Name Function 15:8 MULTMIN[7:0] Sets the Multipath level at which HICUT reaches max band limiting on the L+R channel based on cutoff frequency set by property 0x3609. Si475x/5xC-A55, Default is 10. Range is 0-127%. 7:0 MULTMAX[7:0] Sets the Multipath level at which HICUT begins to band limit on the L+R channel based on cutoff frequency set by property 0x3609. Si475x/5xC-A55, Default is 20. Range is 0-127%. Rev. 0.9 175 AN543 Property 0x3609 FM_HICUT_MULTIPATH_CUTOFF_FREQ The FM_HICUT_MULTIPATH_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency based on Multipath (set by Property 0x3608) on the HICUT engine. You can force a constant cutoff frequency value by setting FREQ_MAX and FREQ_MIN to the same value. To disable the HICUT based on Multipath, set FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0xB428 Si475x/5xC-A55, Default: 0x6419 Units: 100Hz FM_HICUT_MULTIPATH_CUTOFF_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0x64 0x19 2 1 0 Bit Name Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency. Si475x/5xC-A55, Default is 10 kHz. Range is 0-18kHz. 7:0 FREQ_MIN[7:0] Sets the minimum stereo separation. Range is 0-18 kHz. Si475x/5xC-A55, Default is 2.5 kHz. Property 0x360A FM_HICUT_MULTIPATH_ATTACK_TIME The FM_HICUT_MULTIPATH_ATTACK_TIME property sets the transition time for which the HICUT mitigation engine lowers the cutoff frequency based on Multipath. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 16 Si475x/5xC-A55, Default: 100 Units:ms FM_HICUT_MULTIPATH_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0064 Bit 15:0 176 Name ATTACK[15:0] Function Sets the transition time for which the HICUT mitigation engine decreases the cutoff frequency based on Multipath. Si475x/5xC-A55, Default is 100 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x360B FM_HICUT_MULTIPATH_RELEASE_TIME The FM_HICUT_MULTIPATH_RELEASE_TIME property sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on Multipath. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4000 Units: ms FM_HICUT_MULTIPATH_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 Bit 15:0 Name Function RELEASE[15:0] Sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on Multipath. Default is 4000 ms. Range is 1-32767 ms. Property 0x3610 FM_HICUT_USN_THRESHOLDS The FM_HICUT_USN_THRESHOLDS property sets the USN thresholds for HICUT to begin band limiting and reach maximum band limiting on L+R channel based on max and min cutoff frequencies (set by Property 0x3611) on the HICUT engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x250F Units: -dBFS FM_HICUT_USN_THRESHOLDS 15 14 13 12 11 10 9 8 7 6 5 4 3 USNMIN[7:0] USNMAX[7:0] 0x25 0x0F 2 1 0 Bit Name Function 15:8 USNMIN[7:0] Sets the USN level at which HICUT reaches max band limiting on the L+R channel based on cutoff frequency set by property 0x3611. Default is -37 dBFS. Range is 0-127 -dBFS. 7:0 USNMAX[7:0] Sets the Multipath level at which HICUT begins to band limit on the L+R channel based on cutoff frequency set by property 0x3611. Default is -15 dBFS. Range is 0-127 -dBFS. Rev. 0.9 177 AN543 Property 0x3611 FM_HICUT_USN_CUTOFF_FREQ The FM_HICUT_USN_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency based on USN (set by Property 0x3610) on the HICUT engine. You can force a constant cutoff frequency value by setting FREQ_MAX and FREQ_MIN to the same value. To disable the HICUT based on USN, set FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0xB428 Si475x/5xC-A55, Default: 0xB419 Units: 100 Hz FM_HICUT_USN_CUTOFF_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0xB4 0x19 2 1 0 Bit Name Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0-18kHz. 7:0 FREQ_MIN[7:0] Sets the minimum stereo separation. Range is 0-18 kHz. Si475x/5xC-A55, Default is 2.5 kHz. Property 0x3612 FM_HICUT_USN_ATTACK_TIME The FM_HICUT_USN_ATTACK_TIME property sets the transition time for which the HICUT mitigation engine lowers the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 16 Si475x/5xC-A55, Default: 100 Units:ms FM_HICUT_USN_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0064 178 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the HICUT mitigation engine lowers the cutoff frequency based on USN. Si475x/5xC-A55, Default is 100 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x3613 FM_HICUT_USN_RELEASE_TIME The FM_HICUT_USN_RELEASE_TIME property sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4000 Units: ms FM_HICUT_USN_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the HICUT mitigation engine increases the cutoff frequency based on USN. Default is 4000 ms. Range is 1-32767 ms. Property 0x3618 FM_HICUTN_CHBW_LIMITS (Si4754/55/56/57 Only) The FM_BLEND_HICUTN_LIMITS property sets the limits for the CHBW input metric on the L+R high cut mitigation engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x0000 Units: 100 Hz FM_HICUTN_CHBW_LIMITS 15 14 13 12 11 10 9 8 7 6 5 4 3 CHBWMAX[7:0] CHBWMIN[7:0] 0x00 0x00 2 1 0 Bit Name Function 15:8 CHBWMAX[7:0] Sets the value of the channel bandwidth that causes maximum cutoff frequency. Default is 0 kHz. Range is 0-15 kHz. 7:0 CHBWMIN[7:0] Sets the value of the channel bandwidth that causes minimum cutoff frequency. Default is 0 Hz. Range is 0-15 kHz. Rev. 0.9 179 AN543 Property 0x3619 FM_HICUTN_CHBW_CUTOFF_FREQ (Si4754/55/56/57 Only) The FM_HICUTN_CHBW_CUTOFF_FREQ property sets the limits for the cutoff frequency when driven by CHBW on the L+R high cut mitigation engine. To force a given setting (either completely on or completely off) set FREQ_MIN = FREQ_MAX. To disable L+R high cut based on CHBW, set FREQ_MIN = FREQ_MAX = 180 (0xB4). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0xB4B4 Units: 100 Hz FM_HICUTN_CHBW_CUTOFF_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0xB4 0xB4 2 1 0 Bit Name Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency for channel bandwidth based L+R high cut. Default is 18 kHz. Range is 0-18 kHz. 7:0 FREQ_MIN[7:0] Sets the minimum cutoff frequency for channel bandwidth based L+R high cut. Default is 18 kHz. Range is 0-18 kHz. Property 0x361A FM_HICUTN_CHBW_ATTACK_TIME The FM_HICUTN_CHBW_ATTACK_TIME property sets the transition time for which the L+R high cut mitigation engine decreases the cutoff frequency based on channel bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 1 Units: ms FM_HICUTN_CHBW_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ATTACK[15:0] 0x0001 180 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the L+R high cut mitigation engine decreases the cutoff frequency based on channel bandwidth. Default is 1 ms. Range is 1-32767 ms. Rev. 0.9 0 AN543 Property 0x361B FM_HICUTN_CHBW_RELEASE_TIME The FM_HICUTN_CHBW_RELEASE_TIME property sets the transition time for which the L+R high cut mitigation engine increases the cutoff frequency based on channel bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 1 Units: ms FM_HICUTN_CHBW_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0001 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the L+R high cut mitigation engine increases the cutoff frequency based on channel bandwidth. Default is 1 ms. Range is 1-32767 ms. Property 0x3700 FM_HIBLEND_RSSI_THRESHOLDS The FM_HIBLEND_RSSI_THRESHOLDS property sets the RSSI thresholds for HIBLEND to begin band limiting and reach maximum band limiting on L-R channel based on max and min cutoff frequency (set by Property 0x3701) on the HIBLEND engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x371B Units: dBV FM_HIBLEND_RSSI_THRESHOLDS 15 14 13 12 11 10 9 8 7 6 5 4 3 RSSIMAX[7:0] RSSIMIN[7:0] 0x37 0x1B 2 1 0 Bit Name Function 15:8 RSSIMAX[7:0] Sets the RSSI level at which HIBLEND begins to band limit on the L-R channel based on cutoff frequency set by property 0x3701. Default is 55 dBV. Range is -20 to 120 dBV. 7:0 RSSIMIN[7:0] Sets the RSSI level at which HIBLEND reaches maximum band limiting on the L-R channel based on cutoff frequency set by property 0x3701. Default is 27 dBV. Range is -20 to 120 dBV. Rev. 0.9 181 AN543 Property 0x3701 FM_HIBLEND_RSSI_CUTOFF_FREQ The FM_HIBLEND_RSSI_CUTOFF_FREQ property sets the maximum and minimum cutoff frequencies based on RSSI (set by Property 0x3700) on the HIBLEND engine. You can force a constant cutoff frequency value by setting FREQ_MAX and FREQ_MIN to the same value. To disable the HIBLEND based on RSSI, set FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0xB41E Si475x/5xC-A55, Default: 0xB419 Units: 100 Hz FM_HIBLEND_RSSI_CUTOFF_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0xB4 0x19 2 1 0 Bit Name Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency. Default is 18 kHz. Range is 0-18 kHz. 7:0 FREQ_MIN[7:0] Sets the minimum stereo separation. Si475x/5xC-A55, Default is 2.5 kHz. Range is 0-18 kHz Property 0x3702 FM_HIBLEND_RSSI_ATTACK_TIME The FM_HIBLEND_RSSI_ATTACK_TIME property sets the transition time for which the HIBLEND mitigation engine lowers the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 4 Si475x/5xC-A55, Default: 100 Units:ms FM_HIBLEND_RSSI_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0064 182 Bit Name Function 15:0 ATTACK[15:0] Sets the transition time for which the HIBLEND mitigation engine lowers the cutoff frequency based on RSSI. Si475x/5xC-A55, Default is 100 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x3703 FM_HIBLEND_RSSI_RELEASE_TIME The FM_HIBLEND_RSSI_RELEASE_TIME property sets the transition time for which the HIBLEND mitigation engine increases the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 8000 Si475x/5xC-A55, Default: 4000 Units: ms FM_HIBLEND_RSSI_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x1FA0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the HIBLEND mitigation engine increases the cutoff frequency based on RSSI. Si475x/5xC-A55, Default is 4000 ms. Range is 1-32767 ms. Property 0x3708 FM_HIBLEND_MULTIPATH_THRESHOLDS The FM_HIBLEND_MULTIPATH_THRESHOLDS property sets the Multipath thresholds for HIBLEND to begin band limiting and reach maximum band limiting on L-R channel based on max and min cutoff frequencies (set by Property 0x3709) on the HIBLEND engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0x193C Si475x/5xC-A55, Default: 0x080F FM_HIBLEND_MULTIPATH_THRESHOLDS 15 14 Bit 15:8 7:0 13 12 11 10 9 8 7 6 5 4 3 MULTMIN[7:0] MULTMAX[7:0] 0x08 0x0F 2 1 0 Name Function MULTMIN[7:0] Sets the Multipath level at which HICUT reaches max band limiting on the L-R channel based on cutoff frequency set by property 0x3709. Si475x/5xC-A55, Default is 8. Si475x-A10 and earlier, and Si475x-A30 and later: Range is 0-127 Si475xA20: Range: 0-100 MULTMAX[7:0] Sets the Multipath level at which HICUT begins to band limit on the L-R channel based on cutoff frequency set by property 0x3709. Si475x/5xC-A55, Default is 15. Si475x-A10 and earlier, and Si475x-A30 and later: Range is 0-127 Si475xA20: Range: 0-100 Rev. 0.9 183 AN543 Property 0x3709 FM_HIBLEND_MULTIPATH_CUTOFF_FREQ The FM_HIBLEND_MULTIPATH_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency based on Multipath (set by Property 0x3708) on the HIBLEND engine. You can force a constant cutoff frequency value by setting FREQ_MAX and FREQ_MIN to the same value. To disable the HIBLEND based on Multipath, set FREQ_MAX = FREQ_MIN = 180 (0xB4). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0xB41E Si475x/5xC-A55, Default: 0x6419 Units: 100 Hz FM_HIBLEND_MULTIPATH_CUTOFF_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0x64 0x19 2 1 0 Bit Name Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency. Si475x/5xC-A55, Default is 10 kHz. Range is 0-18 kHz. 7:0 FREQ_MIN[7:0] Sets the minimum stereo separation. Si475x/5xC-A55, Default is 2.5 kHz. Range is 0-18 kHz. Property 0x370A FM_HIBLEND_MULTIPATH_ATTACK_TIME The FM_HIBLEND_MULTIPATH_ATTACK_TIME property sets the transition time for which the HIBLEND mitigation engine lowers the cutoff frequency based on Multipath. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 4 Si475x/5xC-A55, Default: 100 Units: ms FM_HIBLEND_MULTIPATH_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ATTACK[15:0] 0x0064 184 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the HIBLEND mitigation engine decreases the cutoff frequency based on Multipath. Si475x/5xC-A55, Default is 100 ms. Range is 1-32767 ms. Rev. 0.9 0 AN543 Property 0x370B FM_HIBLEND_MULTIPATH_RELEASE_TIME The FM_HIBLEND_MULTIPATH_RELEASE_TIME property sets the transition time for which the HIBLEND mitigation engine increases the cutoff frequency based on RSSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 8000 Si475x/5xC-A55, Default: 4000 Units: ms FM_HIBLEND_MULTIPATH_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the HIBLEND mitigation engine increases the cutoff frequency based on Multipath. Si475x/5xC-A55, Default is 4000 ms. Range is 1-32767 ms. Property 0x3710 FM_HIBLEND_USN_THRESHOLDS The FM_HIBLEND_USN_THRESHOLDS property sets the USN thresholds for HIBLEND to begin band limiting and reach maximum band limiting on L-R channel based on max and min cutoff frequencies (set by Property 0x3711) on the HIBLEND engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x371E Units: -dBFS FM_HIBLEND_USN_THRESHOLDS 15 14 Bit 13 12 11 10 9 8 7 6 5 4 3 USNMIN[7:0] USNMAX[7:0] 0x37 0x1E Name 2 1 0 Function 15:8 USNMIN[7:0] Sets the USN level at which HIBLEND reaches max band limiting on the L-R channel based on cutoff frequency set by property 0x3711. Default is -55 dBFS. Range is 0-127 -dBFS. 7:0 USNMAX[7:0] Sets the Multipath level at which HIBLEND begins to band limit on the L-R channel based on cutoff frequency set by property 0x3711. Default is -30 dBFS. Range is 0-127 -dBFS. Rev. 0.9 185 AN543 Property 0x3711 FM_HIBLEND_USN_CUTOFF_FREQ The FM_HIBLEND_USN_CUTOFF_FREQ property sets the maximum and minimum cutoff frequency based on USN (set by Property 0x3710) on the HIBLEND engine. You can force a constant cutoff frequency value by setting FREQ_MAX and FREQ_MIN to the same value. To disable the HIBLEND based on USN, set FREQ_MAX = FREQ_MIN = 180 (0xB4.) The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0xB41E Si475x/5xC-A55, Default: 0x9619 Units: 100 Hz FM_HIBLEND_USN_CUTOFF_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0x96 0x19 2 1 0 Bit Name Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency. Si475x/5xC-A55, Default is 15 kHz. Range is 0-18kHz. 7:0 FREQ_MIN[7:0] Sets the minimum stereo separation. Si475x/5xC-A55, Default is 2.5 kHz. Range is 0-18 kHz. Property 0x3712 FM_HIBLEND_USN_ATTACK_TIME The FM_HIBLEND_USN_ATTACK_TIME property sets the transition time for which the HIBLEND mitigation engine lowers the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 4 Si475x/5xC-A55, Default: 100 Units: ms FM_HIBLEND_USN_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0064 186 Bit Name Function 15:0 ATTACK[15:0] Sets the transition time for which the HIBLEND mitigation engine lowers the cutoff frequency based on USN. Si475x/5xC-A55, Default is 100 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x3713 FM_HIBLEND_USN_RELEASE_TIME The FM_HIBLEND_USN_RELEASE_TIME property sets the transition time for which the HIBLEND mitigation engine increases the cutoff frequency based on USN. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 8000 Si475x/5xC-A55, Default: 4000 Units: ms FM_HIBLEND_USN_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0FA0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time for which the HIBLEND mitigation engine increases the cutoff frequency based on USN. Si475x/5xC-A55, Default is 4000 ms. Range is 1-32767 ms. Property 0x3718 FM_HIBLEND_CHBW_LIMITS (Si4754/55/56/57 Only) The FM_HIBLEND_CHBW_LIMITS property sets the limits for the CHBW input metric on the high-blend (L-R high cut) mitigation engine. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x0000 Units: 100 Hz FM_HIBLEND_CHBW_LIMITS 15 14 13 12 11 10 9 8 7 6 5 4 3 CHBWMAX[7:0] CHBWMIN[7:0] 0x00 0x00 2 1 0 Bit Name Function 15:8 CHBWMAX[7:0] Sets the value of the channel bandwidth that causes maximum cutoff frequency. Default is 0 kHz. Range is 0-15 kHz. 7:0 CHBWMIN[7:0] Sets the value of the channel bandwidth that causes minimum cutoff frequency. Default is 0 kHz. Range is 0-15 kHz. Rev. 0.9 187 AN543 Property 0x3719 FM_HIBLEND_CHBW_CUTOFF_FREQ (Si4754/55/56/57 Only) The FM_HIBLEND_CHBW_CUTOFF_FREQ property sets the limits for the cutoff frequency when driven by CHBW on the hi-blend (L-R high cut) mitigation engine. To force a given setting (either completely on or completely off) set FREQ_MIN = FREQ_MAX. To disable the hi-blend (L-R high cut) based on CHBW, set FREQ_MIN = FREQ_MAX = 180 (0xB4). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0xB4B4 Units: 100 Hz FM_HIBLEND_CHBW_CUTOFF_FREQ 15 14 13 Bit 12 11 10 9 8 7 6 5 4 3 FREQ_MAX[7:0] FREQ_MIN[7:0] 0xB4 0xB4 Name 2 1 0 Function 15:8 FREQ_MAX[7:0] Sets the maximum cutoff frequency for channel bandwidth based hiblend (L-R high cut). Default is 18 kHz. Range is 0-18 kHz. 7:0 FREQ_MIN[7:0] Sets the minimum cutoff frequency for channel bandwidth based hiblend (L-R high cut). Default is 18 kHz. Range is 0-18 kHz. Property 0x371A FM_HIBLEND_CHBW_ATTACK_TIME The FM_HIBLEND_CHBW_ATTACK_TIME property sets the transition time for which the hi-blend (L-R high cut) mitigation engine decreases the cutoff frequency based on channel bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 1 Units: ms FM_HIBLEND_CHBW_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 ATTACK[15:0] 0x0001 188 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time for which the hi-blend (L-R high cut) mitigation engine decreases the cutoff frequency based on channel bandwidth. Default is 1 ms. Range is 1-32767 ms. Rev. 0.9 0 AN543 Property 0x371B FM_HIBLEND_CHBW_RELEASE_TIME The FM_HIBLEND_CHBW_RELEASE_TIME property sets the transition time for which the hi-blend (L-R high cut) mitigation engine increases the cutoff frequency based on channel bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 1 Units: ms FM_HIBLEND_CHBW_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x0001 Bit Name 15:0 RELEASE[15:0] Function Sets the transition time for which the hi-blend (L-R high cut) mitigation engine increases the cutoff frequency based on channel bandwidth. Default is 1 ms. Range is 1-32767 ms. Rev. 0.9 189 AN543 Property 0x4000 FM_RDS_INTERRUPT_SOURCE (Si4751/53/55/57 Only) The FM_RDS_INTERRUPT_SOURCE property configures interrupt related to RDS. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x0000 FM_RDS_INTERRUPT_SOURCE 15 14 13 12 11 10 9 8 7 6 5 0x000 4 RDSTPPTY RDSPI 0x000 Bit Name 15:5 Reserved 0 0 2 1 0 0 RDSSYNC RDSRECV 0 0 0 Function Always write 0. RDSTPPTY If set, generates RDS Interrupt when first valid Block B data has been received or if Block B data is different from last valid Block B data. 0 = Disabled. 1 = Enabled. 3 RDSPI If set, generates RDS Interrupt when first valid Block A data has been received or if Block A data is different from last valid Block A data. 0 = Disabled. 1 = Enabled. 2 Reserved 4 1 0 190 3 Always write 0. RDSSYNC If set, generates RDS interrupt when RDS Synchronization status changes. Default is 0. 0 = Disabled. 1 = Enabled. RDSRECV If set, generate an interrupt whenever the RDS FIFO has at least FM_RDS_INTERRUPT_FIFO_COUNT entries. Default is 0 0 = Disabled. 1 = Enabled. Rev. 0.9 AN543 Property 0x4001 FM_RDS_INTERRUPT_FIFO_COUNT (Si4751/53/55/57 Only) The FM_RDS_INTERRUPT_FIFO_COUNT property sets the minimum number of RDS groups stored in the RDS FIFO before RDSRECV is set. RDSRECV is disabled if set to 0. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 FM_RDS_INTERRUPT_FIFO_COUNT 15 14 13 12 11 10 9 8 7 6 5 4 3 0x00 DEPTH[7:0] 0x00 0x00 Bit Name 15:8 Reserved 7:0 DEPTH[7:0] 2 1 0 Function Always write 0. Sets the minimum number of RDS Groups stored in the RDS FIFO required before RDSRECV is set. RDSRECV is disabled if set to 0. Default is 0. Range is 0-25 Rev. 0.9 191 AN543 Property 0x4002 FM_RDS_CONFIG (Si4751/53/55/57 Only) The FM_RDS_CONFIG property configures RDS settings to enable RDS processing (RDSEN) and set RDS block error thresholds. When a RDS Group is received, all block errors must be less than or equal to the associated block error threshold for the group to be stored in the RDS FIFO. If blocks with errors are permitted into the FIFO, the block error information can be reviewed when the group is read using the FM_RDS_STATUS command. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x0000 FM_RDS_CONFIG 15 14 13 12 11 10 9 8 0x00 Name 15:8 Reserved 7:6 192 BLETHB[1:0] 5:4 BLETHCD[1:0] 3:1 Reserved 0 RDSEN 6 5 4 BLETHB[1:0] BLETHCD[1:0] 0x00 Bit 7 0x0 0x0 3 2 1 0 0x0 RDSEN 0x0 0 Function Always write 0. Block Error Threshold BLOCKB. Block B is most critical because it tells what C and D contain. 0 = No errors. 1 = 1-2 bit errors detected and corrected. 2 = 3-5 bit errors detected and corrected. 3 = Uncorrectable. Block Error Threshold for BLOCKC and BLOCKD. 0 = No errors. 1 = 1-2 bit errors detected and corrected. 2 = 3-5 bit errors detected and corrected. 3 = Uncorrectable. Always write 0. Enables RDS processing. Default is 0. 0 = RDS Disabled. 1 = RDS Enabled. Rev. 0.9 AN543 Property 0x4003 FM_RDS_CONFIDENCE (Si4751/53/55/57 Only) The FM_RDS_CONFIDENCE property sets the required receiver confidence level for each RDS block prior to demodulation. A higher confidence requirement will result in more block errors (higher percentage of blocks with BLE = 3) but reduces the chance of decoder errors (lower percentage of blocks that contain incorrect information despite having BLE<3). Higher confidence requirements may result in a decrease in the frequency with which RDS data is stored in the FIFO. Higher block error rate will affect RDS sensitivity tests. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Default: 0x1111 FM_RDS_CONFIDENCE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 CONFIDENCEA[3:0] CONFIDENCEB[3:0] CONFIDENCEC[3:0] CONFIDENCED[3:0] 0x1 0x1 0x1 0x1 Bit 15:12 11:8 7:4 3:0 Name Function CONFIDENCEA[3:0] Sets the decoder error rate threshold for BLOCK A. 0 = Reserved. 1 = Lowest confidence required. A valid and usable confidence threshold. 2-14 = Medium confidence required. High value may result in all blocks being marked as uncorrectable. 15 = Highest confidence required. This setting may result in all blocks being marked as uncorrectable. CONFIDENCEB[3:0] Sets the decoder error rate threshold for BLOCK B. 0 = Reserved. 1 = Lowest confidence required. A valid and usable confidence threshold. 2-14 = Medium confidence required. High value may result in all blocks being marked as uncorrectable. 15 = Highest confidence required. This setting may result in all blocks being marked as uncorrectable. CONFIDENCEC[3:0] Sets the decoder error rate threshold for BLOCK C. 0 = Reserved. 1 = Lowest confidence required. A valid and usable confidence threshold. 2-14 = Medium confidence required. High value may result in all blocks being marked as uncorrectable. 15 = Highest confidence required. This setting may result in all blocks being marked as uncorrectable. CONFIDENCED[3:0] Sets the decoder error rate threshold for BLOCK D. 0 = Reserved. 1 = Lowest confidence required. A valid and usable confidence threshold. 2-14 = Medium confidence required. High value may result in all blocks being marked as uncorrectable. 15 = Highest confidence required. This setting may result in all blocks being marked as uncorrectable. Rev. 0.9 193 AN543 7.3. Commands and Properties for AM Receiver Table 13. AM Receiver Command Summary Number Name 0x40 AM_TUNE_FREQ Tunes the AM receiver to a frequency in 1 kHz steps. 0x41 AM_SEEK_START Initiates a seek for a channel that meets the validation criteria for AM. 0x42 AM_RSQ_STATUS Returns status information about the received signal quality. 0x45 AM_ACF_STATUS Returns status information about automatically controlled features. 0x47 AM_AGC_STATUS Reports the status of AM AGC. 194 Summary Rev. 0.9 AN543 Table 14. AM Receiver Properties Summary Address Name Default Summary A10 A20 A30 A40 0x0200 0x0200 0x0200 0x0200 512 512 512 512 0x000C 0x000C 0x000C 0x000C 12 12 12 12 0x0008 0x0008 0x0008 0x0008 8 8 8 8 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x01F4 0x01F4 0x01F4 0x01F4 500 500 500 500 0x0078 0x0078 0x0078 0x0078 120 120 120 120 0x0080 0x0080 128 128 0x0008 0x0008 8 8 0x0000 0x0000 0 0 0x01F4 0x01F4 500 500 0x0303 AUDIO_PWR_LINE_FILTER 0x0400 AM_SOFT_MUTE_MAX_ATTENUATION 0x0401 AM_SOFT_MUTE_TRIGGER_THRESHOLD 0x0402 AM_SOFT_MUTE_END_THRESHOLD 0x0403 AM_SOFT_MUTE_RELEASE_TIME 0x0404 AM_SOFT_MUTE_ATTACK_TIME 0x0405 AM_SOFT_MUTE_MAX_ATTENUATION_AGC N/A N/A 0x0406 AM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC N/A N/A 0x0407 AM_SOFT_MUTE_END_THRESHOLD_AGC N/A N/A 0x0408 AM_SOFT_MUTE_RELEASE_TIME_AGC N/A N/A Rev. 0.9 A55 0x0200 Selects a 50 or 60 Hz notch filter for power line noise mitigation. 512 0x000C Sets the maximum soft mute attenuation for RSSI/SNR softmute engine. 12 0x0008 Sets the trigger threshold for RSSI/SNR softmute engine. 8 0x0000 Sets the end threshold for RSSI/SNR softmute engine. 0 0x01F4 Sets the maximum soft mute release time in ms for RSSI/SNR softmute engine. 500 0x0078 Sets the maximum soft mute attack time in ms for RSSI/SNR softmute engine. 120 0x0080 Sets the maximum soft mute attenuation for RSSI/SNR+AGC softmute engine. 128 0x0008 Sets the trigger threshold for RSSI/ SNR+AGC softmute engine. 8 0x0000 Sets the end threshold for RSSI/SNR+AGC softmute engine. 0 0x01F4 Sets the maximum soft mute release time in ms for RSSI/SNR+AGC softmute engine. 500 195 AN543 Table 14. AM Receiver Properties Summary (Continued) Address Name Default A10 A20 Summary A30 A40 0x0078 0x0078 120 120 A55 0x0078 Sets the maximum soft mute attack time in ms for RSSI/SNR+AGC softmute engine. 120 0x0409 AM_SOFT_MUTE_ATTACK_TIME_AGC N/A N/A 0x0412 AM_SOFT_MUTE_MAX_ATTENUATION_MOD N/A N/A N/A N/A 0x008C Sets the maximum soft mute attenuation when modulation index is used. 140 0x0413 AM_SOFT_MUTE_THRESHOLD_MOD N/A N/A N/A N/A 0x0E16 Sets the modulation index thresholds for soft mute to start and stop. 3606 0x0414 AM_SOFT_MUTE_RELEASE_TIME_MOD N/A N/A N/A N/A 0x01F4 Sets the maximum soft mute release time in ms when modulation index is used. 500 0x0415 AM_SOFT_MUTE_ATTACK_TIME_MOD N/A N/A N/A N/A 0x0078 Sets the maximum soft mute attack time in ms when modulation index is used. 120 0x0416 AM_SOFT_MUTE_MOD_RSSI N/A N/A N/A N/A 0x0F0D Sets the RSSI level for AM modulation based softmute to enable/disable. 3853 0x0500 AM_AVC_MIN_GAIN 0xF800 0xF800 0xF800 0xF800 -2048 -2048 -2048 -2048 0x0501 AM_AVC_MAX_GAIN 0x27EC 0x27EC 0x27EC 0x27EC 10220 10220 10220 10220 0x0700 AM_AGC_FE_CONFIG 0x0094 0x0094 0xF094 0xF094 148 148 61588 61588 0x0050 0x0050 0x0050 0x0050 0x0708 AM_IF_AGC_ATTACK_MS 80 80 80 80 196 Rev. 0.9 0xF800 Sets the minimum gain for automatic vol-2048 ume control. 0x4272 Sets the maximum gain for automatic vol17010 ume control. 0xF094 Specifies the input path for the RF signal 61588 and other front-end configuration options. 0x0050 Sets the number of milliseconds the IF highpeak detector must be exceeded before 80 attenuating the appropriate block. AN543 Table 14. AM Receiver Properties Summary (Continued) Address 0x0709 0x070C Name AM_IF_AGC_RELEASE_MS AM_RF_AGC_ATTACK_MS Default Summary A10 A20 A30 A40 0x0050 0x0324 0x0324 0x0324 80 804 804 804 0x0008 0x0008 0x0008 0x0008 8 8 8 8 0x0320 0x0320 0x0320 0x0320 800 800 800 800 0x5104 0x5104 0x5104 0x5104 20740 20740 20740 20740 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0 0 0 0x0050 0x0050 80 80 0x0000 0x0000 0 0 0x070D AM_RF_AGC_RELEASE_MS 0x070E AM_LNA_PD_THRESHOLD 0x0710 AM_AGC_OVERRIDE 0x071B AM_AGC_RSSI_OFFSET N/A 0x1006 AM_SEEK_TUNE_CHBW_HOLD_TIME N/A N/A 0x1007 AM_TUNE_CHBW N/A N/A 0x1100 AM_SEEK_BAND_BOTTOM 0x0208 0x0208 0x0208 0x0208 520 520 520 520 Rev. 0.9 A55 0x0324 Sets the number of milliseconds the IF low peak detector must not be exceeded before 804 increasing the gain of the appropriate block. 0x0008 Sets the number of milliseconds the wideband RF high-peak detector must be exceeded before attenuating the appropri8 ate AGC block. 0x0320 Sets the number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the 800 appropriate block. 0x5904 Sets the high threshold and hysteresis for 22788 the LNA peak detector. 0x0000 Overrides the AGC setting by disabling the AGC and forcing the gain to be maximum. 0 0x0000 Offsets the RSSI value so that it can take into account front-end gain/loss. 0 0x0050 Sets the length of time CHBW is held in units of ms. 80 0x0000 Sets the maximum CHBW allowed during the normal tune. 0 0x020A Sets the lower seek boundary of the AM band in multiples of 1 kHz. 522 197 AN543 Table 14. AM Receiver Properties Summary (Continued) Address Name 0x1101 AM_SEEK_BAND_TOP 0x1102 AM_SEEK_FREQUENCY_SPACING 0x1104 AM_SEEK_CHBW 0x1200 AM_RSQ_INTERRUPT_SOURCE 0x1201 AM_RSQ_SNR_HIGH_THRESHOLD 0x1202 AM_RSQ_SNR_LOW_THRESHOLD 0x1203 AM_RSQ_RSSI_HIGH_THRESHOLD 0x1204 AM_RSQ_RSSI_LOW_THRESHOLD 0x1300 AM_ACF_INTERRUPT_SOURCE 0x1301 AM_ACF_SM_THRESHOLD 198 Default Summary A10 A20 A30 A40 0x06AE 0x06AE 0x06AE 0x06AE 1710 1710 1710 1710 0x000A 0x000A 0x000A 0x000A 10 10 10 10 N/A N/A 0x0014 0x0014 0x0014 20 20 20 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x007F 0x007F 0x007F 0x007F 127 127 127 127 0xFF80 0xFF80 0xFF80 0xFF80 -128 -128 -128 -128 0x007F 0x007F 0x007F 0x007F 127 127 127 127 0xFF80 0xFF80 0xFF80 0xFF80 -128 -128 -128 -128 0x0000 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0 0x001F 0x001F 0x001F 0x001F 0x001F 31 31 31 31 31 Rev. 0.9 A55 0x06AE Sets the upper seek boundary for the AM band in multiples of 1 kHz. 1710 0x0009 Sets the frequency spacing for the AM band in multiples of 1 kHz when performing a 9 seek. Sets the CHBW during the seek. 0x0000 Configures interrupt related to Received Signal Quality metrics (AM_RSQ_STA0 TUS). 0x007F Sets high threshold, which triggers the RSQ interrupt if the SNR is above this threshold. 127 0xFF80 Sets low threshold, which triggers the RSQ interrupt if the SNR is below this threshold. -128 0x007F Sets high threshold, which triggers the RSQ interrupt if the RSSI is above this threshold. 127 0xFF80 Sets low threshold, which triggers the RSQ interrupt if the RSSI is below this threshold. -128 Enables the ACF interrupt sources. Sets the softmute interrupt threshold in dB. AN543 Table 14. AM Receiver Properties Summary (Continued) Address Name Default Summary A10 A20 A30 A40 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x004B 0x004B 0x004B 0x004B 75 75 75 75 0x0005 0x0005 0x0005 0x0005 5 5 5 5 0x0024 0x0024 0x0024 0x0024 36 36 36 36 0x0005 0x0005 0x0005 0x0005 5 5 5 5 0x000A 0x000A 0x000A 0x000A 10 10 10 10 0x1302 AM_ACF_CHBW_THRESHOLD 0x1303 AM_ACF_HICUT_THRESHOLD 0x1306 AM_ACF_CONTROL_SOURCE 0x2000 AM_VALID_MAX_TUNE_ERROR 0x2001 AM_VALID_RSSI_TIME 0x2002 AM_VALID_SNR_TIME 0x2003 AM_VALID_SNR_THRESHOLD 0x2004 AM_VALID_RSSI_THRESHOLD 0x200C AM_VALID_FREQOFF_SCALE N/A N/A N/A 0x200D AM_VALID_FREQOFF_FILTER N/A N/A N/A Rev. 0.9 0x0000 0 0x0064 100 A55 0x0000 Sets the Channel Filter Bandwidth interrupt threshold in units of 100 Hz. 0 0x0000 Sets the HICUT interrupt threshold in units of 100 Hz. 0 0x0000 Determines if SNR or RSSI will be used as the controlling metric for ACF features. 0 0x007E Sets the maximum frequency error allowed before setting the AFCRL indicator. 126 0x0005 Sets the amount of time in milliseconds to allow the RSSI metric to settle before evalu5 ating. 0x0024 Sets the amount of time in milliseconds to allow the SNR metric to settle before evalu36 ating. 0x0005 Sets the SNR threshold for a valid AM Seek Tune. 5 0x000A Sets the RSSI threshold for a valid AM Seek Tune. 10 0x0000 Changes FREQOFF from bppm units to some multiple of Hz. 0 0x0064 Changes the amount that FREQOFF is filtered. 100 199 AN543 Table 14. AM Receiver Properties Summary (Continued) Address Name 0x2100 AM_NB_DETECT_THRESHOLD 0x2101 AM_NB_INTERVAL 0x2102 0x2103 0x2104 AM_NB_DELAY AM_SECONDARY_NB_DETECT_THRESHOLD AM_SECONDARY_NB_INTERVAL Default Summary A10 A20 A30 A40 0x0012 0x0012 0x0012 0x0012 18 18 18 18 0x0004 0x0004 0x0004 0x0004 4 4 4 4 0x005D 0x175D 0x3AE8 0x3AE8 93 5981 15080 15080 0x0015 0x0015 0x0015 0x0015 21 21 21 21 0x0004 0x0004 0x0004 0x0004 4 4 4 4 A55 0x0012 Sets the threshold for detecting impulses in dB above the noise floor. 18 0x0004 Sets the interval as the number of samples to be replaced by interpolated clean sam4 ples. 0x3AE8 Delay in units of number of samples from where to select the good samples to 15080 replace the samples corrupted by the impulse. 0x0015 Sets the threshold for detecting impulses in dB above the noise floor. This blanker is used in the presence of strong near-end 21 blockers. 0x0004 Sets the interval that original samples are replaced by interpolated clean samples. This blanker is used in the presence of 4 strong near end blockers. 0x6070 0x2106 AM_NB_STRONG_SIGNAL_SHUTOFF 0x2107 AM_NB_DETECT_DELAY 0x2108 AM_NB_SCHEME 200 NA NA NA NA 0x0008 0x0008 0x0008 0x0008 8 8 8 8 0x0001 0x0000 0x0100 0x0101 1 0 256 257 N/A Rev. 0.9 24688 Sets the RSSI threshold for determining when to turn on/off the noise blanker. 0x0005 Delay in units of number of samples before applying impulse blanking to the original 5 samples. Sets the noise blanking scheme. AN543 Table 14. AM Receiver Properties Summary (Continued) Address Name Default Summary A10 A20 A30 A40 A55 0x0004 0x0004 0x0004 0x0004 0x0002 4 4 4 4 2 N/A N/A N/A 0x1414 0x2314 0x2314 0x2314 5140 8980 8980 8980 0x001E 0x001E 0x001E 0x001E 30 30 30 30 0x000F 0x000F 0x000F 0x000F 15 15 15 15 0x0800 0x0800 0x0800 0x0800 2048 2048 2048 2048 0x0010 0x0010 0x0010 0x0010 16 16 16 16 0x3232 0x3232 0x3232 12850 12850 12850 0x000A 0x000A 0x000A 10 10 10 0x001E 0x001E 0x001E 30 30 30 0x2109 AM_NB_MODE_CONTROL 0x2110 AM_NB_BURST_NOISE_DETECT_THRESHOLD 0x2200 AM_CHBW_SQ_MIN_MAX 0x2201 AM_CHBW_SQ_HIGH_THRESHOLD 0x2202 AM_CHBW_SQ_LOW_THRESHOLD 0x2203 AM_CHBW_SQ_WIDENING_TIME 0x2204 AM_CHBW_SQ_NARROWING_TIME 0x2205 AM_CHBW_ASSI_MIN_MAX N/A 0x2206 AM_CHBW_ASSI_LOW_THRESHOLD N/A 0x2207 AM_CHBW_ASSI_HIGH_THRESHOLD N/A Rev. 0.9 0x0609 1545 Sets the mode for the noise blanker. 0x0000 Sets the threshold for burst noises and number of samples for the blanker. 0 0x2314 Sets the max(IQSNR,SNR) based maximum and minimum channel filter bandwidth 8980 in units of 100 Hz. 0x001E Sets the max (IQSNR,SNR) threshold for maximum channel filter bandwidth. 30 0x000F Sets the max (IQSNR/SNR) threshold for minimum channel filter bandwidth. 15 0x0800 Sets the channel filter bandwidth widening time based on max(IQSNR/SNR) in units of 2048 ms. 0x0010 Sets the channel filter bandwidth narrowing time based on max(IQSNR/SNR) in units of 16 ms. 0x3232 Sets the maximum and minimum channel filter bandwidth as determined by ASSI in 12850 units of 100 Hz. 0x000A Sets the ASSI threshold for maximum channel filter bandwidth. 10 0x001E Sets the ASSI threshold for minimum channel filter bandwidth. 30 201 AN543 Table 14. AM Receiver Properties Summary (Continued) Address Name Default A10 Summary A20 A30 A40 0x0010 0x0010 0x0010 16 16 16 0x0010 0x0010 0x0010 16 16 16 A55 0x0010 Sets the channel filter bandwidth widening time based on ASSI in units of ms. 16 0x2208 AM_CHBW_ASSI_WIDENING_TIME N/A 0x2209 AM_CHBW_ASSI_NARROWING_TIME N/A 0x220A AM_CHBW_RQ_MIN_MAX N/A N/A N/A N/A 0x2314 Sets the RSSI based maximum and minimum channel bandwidth in 100 Hz. 8980 0x220B AM_CHBW_RQ_LOW_THRESHOLD N/A N/A N/A N/A 0x000F Sets RSSI threshold for minimum channel filter bandwidth. 15 0x220C AM_CHBW_RQ_HIGH_THRESHOLD N/A N/A N/A N/A 0x001E Sets RSSI threshold for maximum channel filter bandwidth. 30 0x220D AM_CHBW_RQ_WIDENING_TIME N/A N/A N/A N/A 0x0800 Sets the RSSI based channel filter bandwidth widening time. 2048 0x220E AM_CHBW_RQ_NARROWING_TIME N/A N/A N/A N/A 0x0010 Sets the RSSI based channel filter bandwidth narrowing time. 16 0x2300 AM_DEMOD_MODE 0x0001 0x0001 0x0001 0x0001 0x0100 1 1 1 1 256 0x2301 AM_DEMOD_AFC_RANGE N/A N/A 0x0000 0x0000 0x0000 0 0 0 0x2302 AM_DEMOD_CARRIER_ENH N/A N/A N/A N/A 202 Rev. 0.9 0x0010 Sets the channel filter bandwidth narrowing time based on ASSI in units of ms. 16 0x0014 20 Selects the demodulation scheme. Selects the AFC range. Specify carrier enhance ratio. AN543 Table 14. AM Receiver Properties Summary (Continued) Address Name Default Summary A10 A20 A30 A40 0x0008 0x0008 0x0008 0x0008 8 8 8 8 0x0000 0x0000 0x0000 0x0000 0 0 0 0 0x0010 0x0010 0x0010 0x0010 16 16 16 16 0x07D0 0x07D0 0x07D0 0x07D0 2000 2000 2000 2000 0x280A 0x280A 0x280A 0x280A 10250 10250 10250 10250 0x0000 0x0000 0 0 0x0000 0x0000 0 0 0x3100 AM_HICUT_SQ_HIGH_THRESHOLD 0x3101 AM_HICUT_SQ_LOW_THRESHOLD 0x3102 AM_HICUT_ATTACK_TIME 0x3103 AM_HICUT_RELEASE_TIME 0x3104 AM_HICUT_CUTOFF_FREQ 0x3105 AM_LOWCUT_MIN_FREQ N/A N/A 0x3106 AM_LOWCUT_MAX_FREQ N/A N/A Rev. 0.9 A55 0x0008 Sets the SNR/RSSI based HICUT high SNR/RSSI threshold. 8 0x0000 Sets the SNR/RSSI based HICUT low SNR/ RSSI threshold. 0 0x0010 Sets the HICUT cutoff frequency attack time in ms. 16 0x07D0 Sets the HICUT cutoff frequency release time in ms. 2000 0x280A Sets the HICUT cutoff Max and Min audio 10250 frequencies. 0x0000 Sets the minimum LowCut cutoff audio frequency. 0 0x0000 Sets the maximum LowCut cutoff audio frequency. 0 203 AN543 7.3.1. AM Receiver Commands Command 0x40 AM_TUNE_FREQ The AM_TUNE_FREQ command sets the AM Receiver to tune to a frequency in 1 kHz units. The CTS bit (and optional interrupt) is set when it is safe to send the next command. The ERR bit (and optional interrupt) is set if an invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC interrupt is set when the command completes. This command may only be sent in powerup mode. The command clears the STC bit if it is already set. Command Bit 7 6 5 4 3 2 1 0 0x40 CMD 000000 ARG1 INJSIDE[1:0] ARG2 FREQH[7:0] ARG3 FREQL[7:0] ARG Bit Name 1 7:2 Reserved 1 1:0 2 7:0 3 7:0 Function Always write 000000. INJSIDE[1:0] Selects injection side. 0 = Automatic injection side selection by the tuner. 1 = Force low-side injection. 2 = Force high-side injection. FREQH[7:0] Tune Frequency High Byte. This byte in combination with FREQL selects the tune frequency in units of 1 kHz. In MW mode the valid range is from 520 to 1710 (520-1710 kHz). LW Range is 144 to 288 (144-288 kHz). SW Range is 2300 to 30000 (2300-30000 kHz). FREQL[7:0] Tune Frequency Low Byte. This byte in combination with FREQH selects the tune frequency in units of 1 kHz. In MW mode the valid range is from 520 to 1710 (520-1710 kHz). LW Range is 144 to 288 (144-288 kHz). SW Range is 2300 to 30000 (2300-30000 kHz) Response Bit 7 6 STATUS CTS ERR 204 5 4 XX Rev. 0.9 3 2 1 0 RSQINT X ACFINT STCINT AN543 Command 0x41 AM_SEEK_START The AM_SEEK_START command begins searching for a valid frequency. In order for a station to be considered valid, each of the following thresholds must be met: AM_VALID_SNR_THRESHOLD, AM_VALID_RSSI_THRESHOLD, and AM_VALID_MAX_TUNE_ERROR. Clears any pending STCINT or RSQINT interrupt status. Seek can be cancelled through setting the CANCEL bit in the AM_RSQ_STATUS command. The CTS bit (and optional interrupt) is set when it is safe to send the next command. RSQINT status is only cleared by the AM_RSQ_STATUS command when the RSQACK bit is set. The ERR bit (and optional interrupt) is set if an invalid argument is sent. Note that only a single interrupt occurs if both the CTS and ERR bits are set. The optional STC interrupt is set when the command completes. This command may only be sent in powerup mode. The command clears the STCINT bit if it is already set. Command Bit 7 6 5 4 3 2 SEEKUP WRAP 1 0 0x41 CMD 0000 ARG1 00 ARG Bit Name Function 1 7:4 Reserved Always write 0000. Seek Up/Down. Determines the direction of the search, either UP = 1 or DOWN = 0. 1 3 SEEKUP 1 2 WRAP 1 1:0 Reserved Wrap/Halt. Determines whether the seek should Wrap = 1, or Halt = 0 when it hits the band limit. Always write 00. Response Bit 7 6 STATUS CTS ERR 5 4 XX Rev. 0.9 3 2 1 0 RSQINT X ACFINT STCINT 205 AN543 Command 0x42 AM_RSQ_STATUS The AM_RSQ_STATUS command returns status information about the received signal quality. This command returns Received Signal Strength Indicator (RSSI), Signal to Noise Ratio (SNR), High Side Adjacent Channel Strength (HASSI), Low Side Adjacent Channel Strength (LASSI), Frequency Offset (FREQOFF), and AM Modulation Index (MOD) associated with the desired channel. It also indicates valid channel (VALID) and AFC rail status (AFCRL). This command can be used to check if the received signal is above the RSSI high threshold as reported by RSSIHINT, or below the RSSI low threshold as reported by RSSILINT. It can also be used to check if the signal is above the SNR high threshold as reported by SNRHINT, or below the SNR low threshold as reported by SNRLINT. The command clears the RSQINT, SNRHINT, SNRLINT, RSSIHINT and RSSILINT interrupt bits when RSQACK bit of ARG1 is set. If the condition is still true after the interrupt is cleared another interrupt will fire assuming that bit is enabled in AM_RSQ_INTERRUPT_SOURCE. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Command Bit 7 6 5 4 2 1 0 RSQACK ATTUNE CANCEL STCACK 0x42 CMD 0000 ARG1 ARG Bit Name 1 7:4 Reserved Always write 0000. 1 3 RSQACK Clears RSQINT, SNRHINT, SNRLINT, RSSIHINT, RSSILINT if set. ATTUNE Returns the values of metrics as of tune time. When the ATTUNE bit is set, values returned for RSQ_STATUS are the values calculated at tune and do not change unless another AM_TUNE_FREQ or AM_SEEK_START command is called. This feature can be used to determine why seek stopped at the current station. 1 206 3 2 Function 1 1 CANCEL Aborts a seek or tune currently in progress 0 = Don't abort. 1 = Abort. 1 0 STCACK Clears the STC interrupt status indicator if set. Rev. 0.9 AN543 Response Bit 7 6 STATUS CTS ERR 4 XX XXXX RESP1 RESP 2 5 BLTF X SNRREADY RSSIREADY 3 2 1 0 RSQINT X ACFINT STCINT SNRHINT SNRLINT RSSIHINT RSSILINT X INJSIDE AFCRL VALID RESP 3 READFREQ[15:8] RESP 4 READFREQ[7:0] RESP 5 FREQOFF[7:0] RESP 6 RSSI[7:0] RESP 7 SNR[7:0] RESP 8 XXXXXXXX RESP 9 LASSI[7:0] RESP 10 HASSI[7:0] RESP 11 IQSNR[7:0] RESP 12 MOD[7:0] Rev. 0.9 207 AN543 RESP Bit Name 1 7:4 Reserved Values may vary. SNRHINT SNR Detect High 0 = Received SNR has not exceeded above SNR programmed using AM_RSQ_SNR_HIGH_THRESHOLD. 1 = Received SNR has exceeded above SNR threshold programmed using AM_RSQ_SNR_HIGH_THRESHOLD. SNRLINT SNR Detect Low 0 = Received SNR has not fallen below SNR threshold programmed using AM_RSQ_SNR_LOW_THRESHOLD. 1 = Received SNR has fallen below SNR threshold programmed using AM_RSQ_SNR_LOW_THRESHOLD. RSSIHINT RSSI Detect High 0 = RSSI has not exceeded above RSSI threshold programmed using AM_RSQ_RSSI_HIGH_THRESHOLD. 1 = RSSI has exceeded above RSSI threshold programmed using AM_RSQ_RSSI_HIGH_THRESHOLD. RSSILINT RSSI Detect Low 0 = RSSI has not fallen below RSSI threshold. programmed using AM_RSQ_RSSI_LOW_THRESHOLD. 1 = RSSI has fallen below RSSI threshold programmed using AM_RSQ_RSSI_LOW_THRESHOLD. 1 1 1 1 2 1 0 2 7 BLTF 2 6 Reserved 2 2 208 3 5 4 Function Band Limit Reports if a seek hit the band limit (WRAP = 0 in AM_SEEK_START) or wrapped to the original frequency (WRAP = 1). Values may vary. SNRREADY SNR Status When set, indicates that the SNR metric was read as part of a tune. If this flag is not set once tune completes, the SNR metric was not measured. A metric not measured indicates that a tune was terminated prematurely due to an invalidating condition (i.e., RSSI did not meet the minimum threshold).In this case, tune time RSQ will report 0 for SNR. The normal running SNR is not affected by this flag. 0 = SNR measurement in progress (tune in progress). 1 = SNR measurement ready or not taken (tune completed). RSSIREADY RSSI Status When set, indicates that the RSSI metric was read as part of a tune. If this flag is not set once tune completes, the RSSI metric was not measured. In this case, tune time RSQ will report 0 for RSSI. The normal running RSSI is not affected by this flag. 0 = RSSI measurement in progress (tune in progress). 1 = RSSI measurement ready or not taken (tune completed). Rev. 0.9 AN543 RESP Bit Name Function 2 3 Reserved Values may vary 2 2 INJSIDE Function = Injection side used. 0 = Low-side injection is being used. 1 = High-side injection is being used. 2 1 AFCRL Set if the AFC rails (AFC gets railed if FREQOFF > MAX_TUNE_ERROR). 2 0 VALID Reports if the channel is valid based on the settings of AM_VALID_RSSI_THRESHOLD, AM_VALID_SNR_THRESHOLD, AM_VALID_MAX_TUNE_ERROR. 3,4 15:0 READFREQ[15:0] 5 7:0 6 7:0 RSSI[7:0] Received Signal Strength indicator in dBV (-128 to 127). 7 7:0 SNR[7:0] RF SNR indicator in dB (-128 to 127). 8 7:0 Reserved Values may vary 9 7:0 LASSI[7:0] Low Side Adjacent Channel Strength Indicator reports the Signal + Noise power relative to the carrier. (-128 to 127). 10 7:0 HASSI[7:0] High Side Adjacent Channel Strength Indicator reports the Signal + Noise power relative to the carrier. (-128 to 127). (Available in Si475x-A40 only) I/Q based SNR for AM-SS in dB. This metric is only available if IQSNR is set in AM_DEMOD_MODE Range: -128 to 127 Returns the currently tuned frequency. FREQOFF[7:0] Frequency offset in units of 2 ppm (-128 to 127). 11 7:0 IQSNR[7:0] 12 7:0 MOD[7:0] AM Modulation Index in percent range 0-100. Rev. 0.9 209 AN543 Command 0x45 AM_ACF_STATUS The AM_ACF_STATUS command returns status information about automatically controlled features. This command returns the Soft Mute Attenuation, Channel Filter Bandwidth, and HICUT cutoff frequency associated with the desired channel. If SMUTE bit is high it indicates that is audio is soft muted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Command Bit 7 6 5 4 3 2 1 0 0x45 CMD 0x00 ARG1 ACFACK ARG Bit Name Function 1 7:1 Reserved Always write 0. 1 0 ACFACK If set to 1, clears ACFINT and any ACF interrupt bits. Response Bit 7 6 STATUS CTS ERR RESP1 XX 210 4 XX CHBWH_INT 3 2 1 0 RSQINT X ACFINT STCINT HICUT_INT CHBW_INT SOFTMUTE_INT XX XXXXXXX RESP2 RESP3 5 X SMUTE SMATTN[6:0] RESP4 CHBW[7:0] RESP5 HICUT [7:0] RESP6 XXXXXXXX RESP7 XXXXXXXX RESP8 LOWCUT[7:0] Rev. 0.9 AN543 RESP Bit Name 1 7:6 Reserved 1 5 CHBWH_INT 1 4:3 Reserved 1 2 HICUT_INT Indicates that HICUT cutoff frequency has crossed below the HICUT threshold set by AM_ACF_HICUT_THRESHOLD. 1 1 CHBW_INT Indicates that Channel Filter Bandwidth is less than the threshold set by AM_ACF_CHBW_THRESHOLD. 1 0 SOFTMUTE_INT 2 7:1 Reserved 2 0 SMUTE 3 7 Reserved 3 6:0 SMATTN[6:0] 4 7:0 CHBW[7:0] Channel Filter Bandwidth in 100 Hz. Range: 0-150. 5 7:0 HICUT[7:0] HICUT cutoff frequency in units of 100 Hz. Range: 10-50. 6 7:0 Reserved Values may vary. 7 7:0 Reserved Values may vary. 8 7:0 LOWCUT[7:0] Function Values may vary. (Available in Si475x-A40 only) CHBWH_INT - Indicates that the Channel Bandwidth is greater than the threshold set by ACF_CBW_THRESHOLD. Values may vary. Indicates that SM attenuation has increased above AM_ACF_SM_THRESHOLD. Values may vary. 0 = Audio is not soft muted. 1 = Audio is soft muted. Values may vary. Soft mute attenuation level in dB. Range: 0-31 in Si475x-A30 and earlier, 0-63 in Si475x-A40 and later. (Available in Si475x-A30 and later.) Lowcut cutoff frequency in units of 10Hz. Only available if lowcut is enabled by the AM_LOWCUT_MIN_FREQ property. Range: 1-100 Rev. 0.9 211 AN543 Command 0x47 AM_AGC_STATUS The AM_AGC_STATUS command reports the current status of the AM AGC. The command is complete when the CTS bit (and optional interrupt) is set. This command may only be sent in powerup mode. Command Bit 7 6 5 4 3 2 1 0 3 2 1 0 RSQINT X ACFINT STCINT AMHI AMLO 0x47 CMD Response Bit 7 6 Status CTS ERR 5 4 XX XXXXXX RESP1 RESP 2 AMWHIPC RESP 3 AMWHIPR RESP 4 PGAGAIN[7:0] 212 RESP Bit Name Function 1 7:2 Reserved 1 1 AMHI 0 = AM LNA PD high threshold is not tripped. 1 = AM LNA PD high threshold is tripped. 1 0 AMLO 0 = AM LNA PD low threshold is not tripped. 1 = AM LNA PD low threshold is tripped. 2 7:0 AMWHIPC AM whip capacitive attenuation in dB. Range: 0-37. 3 7:0 AMWHIPR AM whip resistive attenuation in dB. Range: 0-31. 4 7:0 PGAGAIN[7:0] Values may vary. PGA gain in dB. Range: 8-33. Rev. 0.9 AN543 7.3.2. AM Receiver Properties Property 0x0303 AUDIO_PWR_LINE_FILTER (Si4754/55/56/57 Only) The AUDIO_PWR_LINE_FILTER property selects a 50 Hz or 60 Hz notch filter for power line noise mitigation. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in powerup mode. Default: 0x0200 AUDIO_PWR_LINE_FILTER 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 AUTO[2:0] 0 PWRLINEHDWR PWRLINEFLTR 0x0 HARMONICS[4:0] 0 000 0 1 0 0x0 0x00 Bit Name 15 Reserved Always write to 0. 14:12 AUTO[2:0] The number of 60 ms cycles to wait before relieving 50/60 Hz suppression. 0 = disable automatic 50/60 Hz detection/suppression. (The PWRLINEHDWR setting is ignored.) Default: 0 Recommended: 3 Range: 0 to 7 11:10 Reserved Always write to 00. 9 PWRLINEHDWR 8 PWRLINEFLTR 7:5 Reserved 4:0 HARMONICS[4:0] Function Power Line Hardware Suppression 0 = Hardware is disabled. 1 = Hardware is enabled. (Available in Si475x-A30 and earlier only) Power Line noise filter selection 0 = 50 Hz Filter is selected. 1 = 60 Hz Filter is selected. Always write 0. (Available in Si475x-A30 and earlier) Sets the number of 50/60 Hz harmonics rejected by the Power Line Noise filter. Range 0-20. 0 indicates the filter is disabled. Rev. 0.9 213 AN543 Property 0x0400 AM_SOFT_MUTE_MAX_ATTENUATION The AM_SOFT_MUTE_MAX_ATTENUATION property sets the maximum attenuation in dB that will be applied by the softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 12 Units: dB AM_SOFT_MUTE_MAX_ATTENUATION 15 14 12 11 10 9 8 7 6 5 4 3 2 0x000 SMATTN[6:0] 0x000 0x0C Bit Name 15:7 Reserved 6:0 214 13 SMATTN[6:0] 1 0 Function Always write 0. Sets the maximum attenuation in dB that will be applied by the softmute feature. Default is 12 dB. Si476x-A20 and earlier: Range is 0-31. Si476x-A30 and later: Range is 0-63. Rev. 0.9 AN543 Property 0x0401 AM_SOFT_MUTE_TRIGGER_THRESHOLD The AM_SOFT_MUTE_TRIGGER_THRESHOLD property sets the SNR threshold in dB to engage softmute. The CTS bit (and optional interrupt) is set when it is safe to send the next command. If USE_RSSI is set in AM_ACF_CONTROL_SOURCE property, then property 0x0401 refers to RSSI threshold. This property may only be set or read in powerup mode. Default: 8 Units: dB AM_SOFT_MUTE_TRIGGER_THRESHOLD 15 14 13 12 10 9 8 7 6 5 4 3 0x00 SMTRGTH[7:0] 0x00 0x08 Bit Name 15:8 Reserved 7:0 11 SMTRGTH[7:0] 2 1 0 Function Always write 0. Sets the SNR threshold in dB to engage softmute. Default is 8 dB. (Si475x-A10 and earlier) Range is 0-15 dB. (Si475x-A20 and later) Range is -127-127 dB. Rev. 0.9 215 AN543 Property 0x0402 AM_SOFT_MUTE_END_THRESHOLD The AM_SOFT_MUTE_END_THRESHOLD property sets the SNR threshold in dB at which softmute attenuation will be set to its maximum value. When the SNR is at this level or lower, the audio attenuation will be set to AM_SOFT_MUTE_MAX_ATTENUATION. The CTS bit (and optional interrupt) is set when it is safe to send the next command. If USE_RSSI is set in AM_ACF_CONTROL_SOURCE property, then property 0x0402 refers to RSSI threshold. This property may only be set or read in powerup mode. Default: 0 Units: dB AM_SOFT_MUTE_END_THRESHOLD 15 14 13 12 10 9 8 7 6 5 4 3 0x00 SMENDTH[7:0] 0x00 0x00 Bit Name 15:8 Reserved 7:0 11 2 1 0 Function Always write 0. SMENDTH[7:0] Sets the SNR threshold in dB at which softmute attenuation will be set to its maximum value given by AM_SOFT_MUTE_MAX_ATTENUATION property. Default is 0 dB. Range is 0 to 15 dB for Si475x-A10 and -127 to 127 dB for Si475x-A20 or later. Property 0x0403 AM_SOFT_MUTE_RELEASE_TIME The AM_SOFT_MUTE_RELEASE_TIME property sets the maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 500 Units: ms AM_SOFT_MUTE_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x01F4 Bit 15:0 216 Name Function RELEASE[15:0] Sets the maximum time in ms it takes to unmute the audio. Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage. Default is 500 ms. Range is 1-32767 ms. Rev. 0.9 AN543 Property 0x0404 AM_SOFT_MUTE_ATTACK_TIME The AM_SOFT_MUTE_ATTACK_TIME property sets the maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 120 Units: ms AM_SOFT_MUTE_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0078 Bit Name Function Sets the maximum time in ms it takes to mute the audio. 15:0 ATTACK[15:0] Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage. Default is 120 ms. Range is 1-32767 ms. Property 0x0405 AM_SOFT_MUTE_MAX_ATTENUATION_AGC (Si4754/55/56/57 Only) When AGC is engaged, the AM_SOFT_MUTE_MAX_ATTENUATION_AGC property sets the maximum attenuation in dB that will be applied by the RSSI/SNR softmute feature. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0x0080 AM_SOFT_MUTE_MAX_ATTENUATION_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 IGNORE_AGC SMATTN[6:0] 0x00 1 0x00 Bit Name 15:8 Reserved 7 IGNORE_AGC 6:0 SMATTN[6:0] 1 0 Function Always write to 0. Selects which set of properties control softmute when AGC is engaged. 0 = Use properties 0x0405-0x0409 when the AGC is engaged, and properties 0x0400-0x0404 otherwise. 1 = Always use only properties 0x0400-0x0404. When AGC is engaged, sets the maximum attenuation in dB that will be applied by the RSSI/SNR softmute feature. Default is 0 dB. Range is 0-63 dB. Rev. 0.9 217 AN543 Property 0x0406 AM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC (Si4754/55/56/57 Only) When AGC is engaged, the AM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC property sets the RSSI/SNR threshold in dB to engage softmute. If USE_RSSI bit is set in AM_ACF_CONTROL_SOURCE property (0x1306), then this property refers to RSSI threshold. If USE_RSSI bit is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 8 Units: dB AM_SOFT_MUTE_TRIGGER_THRESHOLD_AGC 15 218 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SMTRGTH_AGC[7:0] 0x00 0x08 Bit Name 15:8 Reserved 7:0 SMTRGTH_AGC[7:0] 1 0 Function Always write to 0. When AGC is engaged, sets the RSSI/SNR threshold in dB to engage softmute. Default is 8 dB. Range is -127 to 127 dB. Rev. 0.9 AN543 Property 0x0407 AM_SOFT_MUTE_END_THRESHOLD_AGC (Si4754/55/56/57 Only) When AGC is engaged, the AM_SOFT_MUTE_END_THRESHOLD_AGC property sets the RSSI/SNR threshold in dB at which softmute attenuation will be set to its maximum value. When the RSSI/SNR is at this level or lower, the audio attenuation will be set to AM_SOFT_MUTE_MAX_ATTENUATION_AGC. If USE_RSSI bit is set in AM_ACF_CONTROL_SOURCE property (0x1306), then this property refers to RSSI threshold. If USE_RSSI bit is not set, this property refers to SNR threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 0 Units: dB AM_SOFT_MUTE_END_THRESHOLD_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SMTRGTH_AGC[7:0] 0x00 0x00 Bit Name 15:8 Reserved 7:0 SMTRGTH_AGC[7:0] 1 0 Function Always write to 0. When AGC is engaged, sets the RSSI/SNR threshold in dB to engage softmute. Default is 8 dB. Range is -127 to 127 dB. Property 0x0408 AM_SOFT_MUTE_RELEASE_TIME_AGC (Si4754/55/56/57 Only) When AGC is engaged, the AM_SOFT_MUTE_RELEASE_TIME_AGC property sets maximum time in ms it takes to unmute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 500 Units: ms AM_SOFT_MUTE_RELEASE_TIME_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE_AGC[15:0] 0x01F4 Bit 15:0 Name Function Sets the maximum time in ms it takes to unmute the audio. Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can RELEASE_AGC[15:0] engage/disengage. Default is 500 ms. Range is 1-32767 ms. Rev. 0.9 219 AN543 Property 0x0409 AM_SOFT_MUTE_ATTACK_TIME_AGC (Si4754/55/56/57 Only) When AGC is engaged, the AM_SOFT_MUTE_ATTACK_TIME_AGC property sets maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 120 Units: ms AM_SOFT_MUTE_ATTACK_TIME_AGC 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK_AGC[15:0] 0x0078 Bit Name 15:0 Function ATTACK_AGC[15:0] Sets the maximum time in ms it takes to unmute the audio. Note that there will be 16 ms of filter delay for RSSI/SNR metric before softmute can engage/disengage. Default is 120 ms. Range is 1-32767 ms. Property 0x0412 AM_SOFT_MUTE_MAX_ATTENUATION_MOD The AM_SOFT_MUTE_MAX_ATTENUATION_MOD property sets the maximum soft mute attenuation when modulation index is used. The feature is disabled by default by setting IGNORE[7]=1. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, this property is not available Si475x/5xC-A55, Default: 0x008C AM_SOFT_MUTE_MAX_ATTENUATION_MOD 15 14 13 12 10 9 8 7 6 5 4 3 2 0x00 IGNORE SMATTN[6:0] 0x00 1 0x0C Bit Name 15:8 0x00 7 IGNORE 6:0 SMATTN[6:0] 220 11 1 0 Function Always write 0 0 = enable the modulation based soft mute 1 = disable the modulation based soft mute Sets the maximum attenuation in dB that will be applied by the softmute feature. Default is 12 dB. Range is 0 ~ 63. Rev. 0.9 AN543 Property 0x0413 AM_SOFT_MUTE_THRESHOLD_MOD The AM_SOFT_MUTE_THRESHOLD_MOD property sets the modulation index threshold for soft mute to start and stop. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available. Si475x/5xC-A55, Default: 0x0E16 Units: % AM_SOFT_MUTE_THRESHOLD_MOD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0 SMENDTH[6:0] 0 SMTRGTH[6:0] 0 0x0E 0 0x16 Bit Name 15 0 14:8 SMENDTH[6:0] 7 0 6:0 SMTRGTH[6:0] 1 0 Function Always write to 0 Sets the soft mute end threshold in percentage, the conversion between property value and threshold in percentage is SMENDTH[6:0] = threshold x 1.27. Default is 14. Range is 0 ~ 127. Always write to 0 Sets the soft mute start threshold in percentage, the conversion between property value and threshold in percentage is SMTRGTH[6:0] = threshold x 1.27. Default is 22, Range is 0 ~127. Property 0x0414 AM_SOFT_MUTE_RELEASE_TIME_MOD The AM_SOFT_MUTE_RELEASE_TIME_MOD property sets the maximum soft mute release time in ms when modulation index is used. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, this property is not available. Si475x/5xC-A55, Default: 500 ms AM_SOFT_MUTE_RELEASE_TIME_MOD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x01F4 Bit Name 15:0 RELEASE [15:0] Function Sets the maximum time in ms to unmute the audio. Default is 500 ms. Range is 1 ~ 32767 ms. Rev. 0.9 221 AN543 Property 0x0415 AM_SOFT_MUTE_ATTACK_TIME_MOD The AM_SOFT_MUTE_ATTACK_TIME_MOD property sets maximum time in ms it takes to mute the audio. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier: This property is not available. Si475x/5xC-A55, Default: 120 Units: ms AM_SOFT_MUTE_ATTACK_TIME_MOD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0078 Bit Name Function 15:0 ATTACK [15:0] Sets the maximum time in ms to unmute the audio. Default is 120 ms. Range is 1-32767 ms. Property 0x0416 AM_SOFT_MUTE_MOD_RSSI The AM_SOFT_MUTE_MOD_RSSI property sets the RSSI level for AM modulation based soft mute to enable or disable. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, this property is not available Si475x/5xC-A55, Default: 0x0F0D Units: dBV AM_SOFT_MUTE_MOD_RSSI 15 14 13 12 11 10 9 8 7 6 5 4 3 XMAX[7:0] XMIN[7:0] 0x0F 0x0D 2 1 0 Bit Name Function 15:8 XMAX [15:8] Sets RSSI level above which the AM modulation based soft mute will be automatically switched off. Default is 15 dBV. Range is -127 ~ 127 dBV. 7:0 XMIN[7:0] Sets RSSI level below which the AM modulation based soft mute will be automatically switched on. Default is 13 dBV. Range is -127 ~ 127 dBV 222 Rev. 0.9 AN543 Property 0x0500 AM_AVC_MIN_GAIN The AM_AVC_MIN_GAIN property sets the minimum gain for automatic volume control. The minimum gain value is given by MINGAIN = g x 170 where g is the desired minimum AVC gain in dB. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: -2048 AM_AVC_MIN_GAIN 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 MINGAIN[15:0] 0xF800 Bit Name Function 15:0 MINGAIN[15:0] The minimum gain value for the AVC. Gain in dB is MINGAIN x 6.02/1024. Range for MINGAIN is -4096 to 0. This implies that the range of g is -24 dB to 0 dB Rev. 0.9 223 AN543 Property 0x0501 AM_AVC_MAX_GAIN The AM_AVC_MAX_GAIN property sets the maximum gain for automatic volume control. The maximum gain value is given by MAXGAIN = g x 170 where g is the desired maximum AVC gain in dB. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 10220 Si475x/5xC-A55, Default: 17010 AM_AVC_MAX_GAIN 15 14 13 12 11 10 9 0 8 7 6 5 4 3 2 1 0 MAXGAIN[14:0] 0x27EC 0 Bit Name Function 15 Reserved 14:0 MAXGAIN[14:0] Always set to 0. The maximum gain value for the AVC. Gain in dB is MAXGAIN x 6.02/1024. Range is 0-32767. This implies that the range of g is 0-193 dB Property 0x0700 AM_AGC_FE_CONFIG Specifies the input path for the RF signal and other front-end configuration options. The CTS bit (and optional interrupt) is set when it is safe to send the next command. The property may only be set or read when in the powerup mode. Changes to this property take effect after the next tune is completed. Default: 0x0094 AM_AGC_FE_CONFIG 15 224 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0000000 FMLNAZ 10 ATTENFM HARMREJ INPUTSELECT[3:0] 0000000 0 10 0 1 0x4 Rev. 0.9 AN543 Bit Name Function 15:9 Reserved In Si475x-A20 and earlier, always write 0000000. In Si475x-A30 and later, always write 1111000. 8 FMLNAZ 0 = Normal LNA mode where the LNA input impedance is 50 1 = LNA loopthru mode where LNA input impedance is 100 7:6 Reserved Always write to 10. 5 ATTENFM 0 = FM attenuators are turned on to improve FM intrusion. 1 = FM attenuators are off. This is the preferred setting to minimize desensitization for a multiple receiver system sharing a single antenna. 4 HARMREJ 0 = Harmonic reject is disabled. 1 = Harmonic reject is enabled. 3:0 INPUTSELECT[3:0] 4 = Receive signal comes into the AMI Rev. 0.9 225 AN543 Property 0x0708 AM_IF_AGC_ATTACK_MS Sets the number of milliseconds the IF high peak detector must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3-5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Default: 80 Units: ms AM_IF_AGC_ATTACK_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 IF_AGC_ATTACK_MS[15:0] 0x0050 Bit Name 15:0 Function Number of milliseconds the IF high peak detector must be exceeded before attenuating the appropriate block. IF_AGC_ATTACK_MS[15:0] Si475x-A10 and earlier: Range: 4-248 ms. Si475x-A20 and later: Range: 4-4096 ms. Property 0x0709 AM_IF_AGC_RELEASE_MS Sets the number of milliseconds the IF low peak detector must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled once every 3-5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read when in the powerup mode. Si475x-A10 and earlier, Default: 80 Si475x-A30 and later, Default: 804 Units: ms AM_IF_AGC_RELEASE_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 IF_AGC_RELEASE_MS[15:0] 0x0324 Bit 15:0 Name IF_AGC_RELEASE_MS[15:0] Function Number of milliseconds the IF low peak detector must not be exceeded before increasing the gain of the appropriate block. Si475x-A10 Range: 4-248 ms Si475x-A20 and later, Range: 4-4096 ms Note: For best performance AM_IF_AGC_RELEASE_MS > AM_RF_AGC_RELEASE_MS and set AM_IF_AGC_RELEASE_MS to 804 ms for AM_RF_AGC_RELEASE_MS of 800 ms. 226 Rev. 0.9 0 AN543 Property 0x070C AM_RF_AGC_ATTACK_MS The AM_RF_AGC_ATTACK_MS property sets the number of milliseconds the wideband RF high-peak detector must be exceeded before attenuating the appropriate block. The peak detectors are only sampled once every 3- 5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 8 Units: ms AM_RF_AGC_ATTACK_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RF_AGC_ATTACK_MS[15:0] 0x0008 Bit 15:0 Name Function RF_AGC_ATTACK_MS[15:0] Number of milliseconds the wide-band RF high-peak detector must be exceeded before attenuating the appropriate block. Default is 8 ms. Si475x-A10 and earlier: Range: 4-248 ms. Si475x-A20 and later: Range: 4-4096 ms. Rev. 0.9 227 AN543 Property 0x070D AM_RF_AGC_RELEASE_MS The AM_RF_AGC_RELEASE_MS property sets the number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. The peak detectors are only sampled once every 3-5 ms. If the peak detector trips, the internal counter is incremented by 4 ms. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 800 Units: ms AM_RF_AGC_RELEASE_MS 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RF_AGC_RELEASE_MS[15:0] 0x0320 Bit 15:0 Name Function RF_AGC_RELEASE_MS[15:0] Number of milliseconds the wideband RF low-peak detector must not be exceeded before increasing the gain of the appropriate block. Default is 800 ms. (Si475x-A10 and earlier) Range: 4-248 ms. (Si475x-A20 and later) Range is 4-4096 ms. Note: For best performance, AM_IF_AGC_RELEASE_MS > AM_RF_AGC_RELEASE_MS 228 Rev. 0.9 AN543 Property 0x070E AM_LNA_PD_THRESHOLD The AM_LNA_PD_THRESHOLD property sets the high threshold and hysteresis for the LNA peak detector. The high threshold sets the level at which the AGC increases attenuation. The hysteresis is how many dB below the high threshold the level must drop before the AGC decreases attenuation. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0x5104 Si475x/5xC-A55, Default: 0x5904 AM_LNA_PD_THRESHOLD 15 14 Bit 15:8 7:0 13 12 11 10 9 8 7 6 5 4 3 HIGH[7:0] HYST[7:0] 0x51 0x04 Name 2 1 0 Function HIGH[7:0] Sets the level in dBV at which AGC increases attenuation. HIGH[7:0] Range: 79-93. 79 = 79 dBV. 81 = 81 dBV. 83 = 83 dBV. 85 = 85 dBV. 87 = 87 dBV. 89 = 89 dBV. 91 = 91 dBV. 93 = 93 dBV. HYST[7:0] Sets how many dB below the high threshold the level must drop before the AGC decreases attenuation. HYST[7:0] Range: 3-6. 3 = 3 dB. 4 = 4 dB. 5 = 5 dB. 6 = 6 dB. Rev. 0.9 229 AN543 Property 0x0710 AM_AGC_OVERRIDE The AM_AGC_OVERRIDE property overrides the AGC setting by disabling the AGC and forcing the gain to be maximum. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x0000 AM_AGC_OVERRIDE 15 14 13 12 11 Bit Name 15:6 Reserved 5:0 10 9 8 7 6 5 4 3 2 1 0x000 AGC_OVERRIDE[5:0] 0x000 0 0 Function Always write 0. AGC_OVERRIDE[5:0] AGC_OVERRIDE selects whether the AGC is enabled or disabled. 0 = AGC is enabled. 0x3F = AGC is disabled and set to maximum gain. Property 0x071B AM_AGC_RSSI_OFFSET The AM_AGC_RSSI_OFFSET property sets the value of the offset applied to the RSSI value in order to account for the front-end gain/loss due to the AGC. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 and earlier: This property is not available. Si475x-A20 and later, Default: 0 Units: dB AM_AGC_RSSI_OFFSET 15 230 14 13 12 11 10 9 8 7 6 5 4 3 OFFSET[7:0] RSVD[7:0] 0x00 0x00 Bit Name 15:8 OFFSET[7:0] 7:0 Reserved 2 1 Function Sets the RSSI offset value to take into account front-end gain/loss. Default is 0. Range is -128 to 127. Always write 0. Rev. 0.9 0 AN543 Property 0x1006 AM_SEEK_TUNE_CHBW_HOLD_TIME The AM_SEEK_TUNE_CHBW_HOLD_TIME property sets the length of time channel filter bandwidth is held at specified value after Seek or Tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10: This property is not available. Si475x-A20: This feature is not available. Do not write to this property. Si475x-A30 and later, Default: 80 Units: ms AM_SEEK_TUNE_CHBW_HOLD_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 CHBW_HOLD_TIME[15:0] 0x0050 Bit 15:0 Name Function Sets the length of time channel filter bandwidth is held at specified value after Seek or Tune. CHBW_HOLD_TIME[15:0] Default is 80 ms. Range is 4-1000. Property 0x1007 AM_TUNE_CHBW The AM_TUNE_CHBW property sets the maximum channel filter bandwidth to allow during tune. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available Si475x-A30 and later, Default: 0 Units: 100 Hz AM_TUNE_CHBW 15 14 13 12 10 9 8 7 6 5 4 3 0x00 TUNE_CHBW[7:0] 0x00 0x0000 Bit Name 15:8 Reserved 7:0 11 TUNE_CHBW[7:0] 2 1 0 Function Always write to 0. Sets the maximum channel filter bandwidth to allow during tune. Set to 0 to disable limiting of channel filter bandwidth during tune. Default is 0. Range is 0-150. Rev. 0.9 231 AN543 Property 0x1100 AM_SEEK_BAND_BOTTOM The AM_SEEK_BAND_BOTTOM property sets the bottom of the AM band for seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 520 kHz. Si475x-A40 and earlier, Default: 520 Si475x/5xC-A55, Default: 522 Units: kHz AM_SEEK_BAND_BOTTOM 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 AMSKFREQL[15:0] 0x0208 Bit Name 15:0 Function AMSKFREQL[15:0] Sets the bottom of the AM band for seek. Default is 520 kHz. Range: 520-1710 (MW). 144-288 (LW). 2300-30000 (SW). Property 0x1101 AM_SEEK_BAND_TOP The AM_SEEK_BAND_TOP property sets the top of the AM band for seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 1710 kHz Default: 1710 Units: kHz 15 14 13 12 11 10 AM_SEEK_BAND_TOP 9 8 7 6 AMSKFREQH[15:0] 5 4 3 2 0x06AE Bit 15:0 232 Name AMSKFREQH[15:0] Function Sets the top of the AM band for seek. Default is 1710 kHz. Range: 520-1710 (MW). 144-288 (LW) 2300-30000 (SW) Rev. 0.9 1 0 AN543 Property 0x1102 AM_SEEK_FREQUENCY_SPACING The AM_SEEK_FREQUENCY_SPACING property selects frequency spacing for AM seek in multiples of 1 kHz. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 10 kHz. Si475x-A40 and earlier, Default: 10 Si475x/5xC-A55, Default: 9 Units: kHz AM_SEEK_FREQUENCY_SPACING 15 14 13 12 Bit Name 15:5 Reserved 4:0 11 10 9 8 7 6 5 4 3 2 1 0x000 AMSKSPACE[4:0] 0x000 0x0A 0 Function Always write 0. AMSKSPACE[4:0] Selects frequency spacing for AM seek. Default is 10 kHz. Range is 1-31. 5 = SW (5 kHz). 9 = AM in Asia (9 kHz). 9 = LW (9 kHz). 10 = AM in U.S. (10 kHz). Property 0x1104 AM_SEEK_CHBW The AM_SEEK_CHBW property sets the channel filter bandwidth during seek. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available. Si475x-A30 and later, Default: 20 Units: 100 Hz 15 14 13 12 11 10 9 AM_SEEK_CHBW 8 7 6 5 4 3 0x00 SEEK_CHBW[7:0] 0x00 0x14 Bit Name 15:8 Reserved 7:0 SEEK_CHBW[7:0] 2 1 0 Function Always write to 0. Sets the maximum channel filter bandwidth to allow during seek. Default is 2 kHz. Range is 0-150. Rev. 0.9 233 AN543 Property 0x1200 AM_RSQ_INTERRUPT_SOURCE The AM_RSQ_INTERRUPT_SOURCE property configures interrupt related to Received Signal Quality metrics. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. The default is 0. Default: 0 AM_RSQ_INTERRUPT_SOURCE 15 14 13 12 11 10 9 8 7 6 5 0x000 4 3 2 1 SNRHINT SNRLINT RSSIHINT RSSILINT 0x000 0 0 0 Bit Name 15:4 Reserved Always write 0. 3 SNRHINT 0: Disable Interrupt. 1: Enable interrupt to occur if SNR goes above the threshold set by AM_RSQ_SNR_HIGH_THRESHOLD. 2 SNRLINT 0: Disable Interrupt. 1: Enable interrupt to occur if SNR goes below the threshold set by AM_RSQ_SNR_LOW_THRESHOLD. 1 RSSIHINT 0: Disable Interrupt. 1: Enable interrupt to occur if RSSI goes above the threshold set by AM_RSQ_RSSI_HIGH_THRESHOLD. RSSILINT 0: Disable Interrupt. 1: Enable interrupt to occur if RSSI goes below the threshold set by AM_RSQ_RSSI_LOW_THRESHOLD. 0 234 0 Function Rev. 0.9 0 AN543 Property 0x1201 AM_RSQ_SNR_HIGH_THRESHOLD The AM_RSQ_SNR_HIGH_THRESHOLD property sets the high threshold, which triggers the RSQ interrupt if the SNR is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 127 Units: dB 15 14 13 12 11 SIGN[7:0] AM_RSQ_SNR_HIGH_THRESHOLD 10 9 8 7 6 5 4 3 SNRH[7:0] 0x00 Bit Name 15:8 SIGN[7:0] 7:0 SNRH [7:0] 2 1 0 0x7F Function Write 0 for (+) values, 0xFF for (-) values. Sets the high threshold, which triggers the RSQ interrupt if the SNR is above this threshold. Default is 127 dB. Range is -128 to 127 dB in steps of 1 dB. Property 0x1202 AM_RSQ_SNR_LOW_THRESHOLD The AM_RSQ_SNR_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the SNR is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: -128 Units: dB AM_RSQ_SNR_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 SIGN[7:0] SNRL[7:0] 0xFF 0x80 2 1 0 Bit Name Function 15:8 SIGN[7:0] Write 0 for (+) values, 0xFF for (-) values. 7:0 SNRL [7:0] Sets low threshold, which triggers the RSQ interrupt if the SNR is below this threshold. Default is -128 dB. Range is -128 to 127 dB in steps of 1 dB. Rev. 0.9 235 AN543 Property 0x1203 AM_RSQ_RSSI_HIGH_THRESHOLD The AM_RSQ_RSSI_HIGH_THRESHOLD property sets high threshold, which triggers the RSQ interrupt if the RSSI is above this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 127 Units: dBV AM_RSQ_RSSI_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 SIGN[7:0] RSSIH[7:0] 0x00 0x7F Bit Name 15:8 SIGN[7:0] 7:0 RSSIH [7:0] 2 1 0 Function Write 0 for (+) values, 0xFF for (-) values. Sets high threshold, which triggers the RSQ interrupt if the RSSI is above this threshold. Default is 127 dBV. Range is -128 to 127 dBV in steps of 1 dB. Property 0x1204 AM_RSQ_RSSI_LOW_THRESHOLD The AM_RSQ_RSSI_LOW_THRESHOLD property sets low threshold, which triggers the RSQ interrupt if the RSSI is below this threshold. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: -128 Units: dBV 15 14 13 12 11 SIGN[7:0] AM_RSQ_RSSI_LOW_THRESHOLD 10 9 8 7 6 5 4 3 RSSIL[7:0] 0xFF Bit Name 15:8 SIGN[7:0] 7:0 RSSIL [7:0] 236 2 1 0 0x80 Function Write 0 for (+) values, 0xFF for (-) values. Sets low threshold, which triggers the RSQ interrupt if the RSSI is below this threshold. Default is -128 dBV. Range is -128 to 127 dBV in steps of 1 dB. Rev. 0.9 AN543 Property 0x1300 AM_ACF_INTERRUPT_SOURCE The AM_ACF_INTERRUPT_SOURCE property enables the ACF interrupt sources. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 AM_ACF_INTERRUPT_SOURCE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0x000 CHBWH_INT 00 HICUT_INT CHBW_INT SOFTMUTE_INT 0x000 0 00 0 0 0 Bit Name 15:6 Reserved Function Always write 0. (Available in Si475x-A40 only) Enables the Channel Filter Bandwidth High Interrupt 0 = The Channel Bandwidth interrupt is disabled 1 = The Channel Bandwidth interrupt is enabled 5 CHBWH_INT 4:3 Reserved 2 HICUT_INT When set, enables the HICUT Interrupt. Default is 0. 0 = The HICUT interrupt is disabled. 1 = The HICUT interrupt is enabled. 1 CHBW_INT When set, enables the Channel Filter Bandwidth Interrupt. Default is 0. 0 = The Channel Filter Bandwidth interrupt is disabled. 1 = The Channel Filter Bandwidth interrupt is enabled. 0 SOFTMUTE_INT Always write 0. When set, enables the softmute interrupt. Default is 0. 0 = The softmute interrupt is disabled. 1 = The softmute interrupt is enabled. Rev. 0.9 237 AN543 Property 0x1301 AM_ACF_SM_THRESHOLD The AM_ACF_SM_THRESHOLD property sets the softmute interrupt threshold in dB. When softmute attenuation rises above the level set by this property and the SOFTMUTE_INT interrupt is enabled through the AM_ACF_INTERRUPT_SOURCE property, the SOFTMUTE_INT interrupt will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 31 Units: dB AM_ACF_SM_THRESHOLD 15 14 13 12 11 8 7 6 5 4 3 2 1 SMATTN_THRESH[4:0] 0x000 0x1F Name 15:5 Reserved 238 9 0x000 Bit 4:0 10 0 Function Always write 0. Softmute interrupt threshold in dB which triggers the softmute interrupt when SMATTN_THRESH[4:0] the softmute attenuation rises above this level. Default is 31 dB. Range is 0-31 dB. Rev. 0.9 AN543 Property 0x1302 AM_ACF_CHBW_THRESHOLD The AM_ACF_CHBW_THRESHOLD property sets the Channel Filter Bandwidth interrupt threshold in units of 100 Hz. When the Channel Filter Bandwidth falls below this threshold and the CHBW_INT interrupt is enabled through the AM_ACF_INTERRUPT_SOURCE property, the CHBW_INT interrupt will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 Units: 100 Hz AM_ACF_CHBW_THRESHOLD 15 14 Bit 13 12 11 10 9 8 7 6 5 4 3 2 CHBW_THRESH_HIGH[7:0] CHBW_THRESH[7:0] 0x00 0x00 Name 1 0 Function 15:8 (Available in Si475x-A40 and later only) Channel Filter Bandwidth High interrupt threshold in units of 100 Hz, CHBW_THRESH_HIGH[7:0] which triggers the Channel Filter Bandwidth Interrupt when the channel filter bandwidth rises above this threshold. Default is 0 kHz. Range is 0-255. 7:0 Channel Filter Bandwidth Low interrupt threshold in units of 100 Hz, which triggers the Channel Filter Bandwidth Interrupt when the Channel Filter Bandwidth falls below this threshold. Default is 0 kHz. Range is 0-255. CHBW _THRESH[7:0] Rev. 0.9 239 AN543 Property 0x1303 AM_ACF_HICUT_THRESHOLD The AM_ACF_HICUT_THRESHOLD property sets the HICUT interrupt threshold in units of 100 Hz. When the HICUT cutoff frequency falls below this threshold and the HICUT_INT interrupt is enabled through the AM_ACF_INTERRUPT_SOURCE property, the HICUT_ INT interrupt will be asserted. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 Units: 100 Hz AM_ACF_HICUT_THRESHOLD 15 14 12 11 10 9 8 7 6 5 4 3 2 0x00 HICUT_THRESH[7:0] 0x00 0x00 Bit Name 15:8 Reserved 7:0 240 13 1 0 Function Always write 0. HICUT interrupt threshold in units of 100 Hz, which triggers the HICUT InterHICUT_THRESH[7:0] rupt when the HICUT cutoff frequency falls below this threshold. Default is 0 kHz. Range is 0-200. Rev. 0.9 AN543 Property 0x1306 AM_ACF_CONTROL_SOURCE The AM_ACF_CONTROL_SOURCE property determines if SNR or RSSI will be used as the controlling metric for ACF features. This will affect all automatically controlled features that are controlled by SNR. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 AM_ACF_CONTROL_SOURCE 15 14 13 12 11 10 9 8 7 6 5 4 0x0000 0x0000 3 2 AFC_DIS AFC_SM 0 0 Bit Name 15:4 Reserved Always write 0. 3 AFC_DIS When set, disables the use of AFC in tune validation 0 = Use AFC in tune validation. 1 = Do not use AFC in tune validation. 2 AFC_SM When set, softmute will be triggered by an AFC rail. (Si475x-A20 and later only). 0 = Do not use AFC rail to force softmute. 1 = Use AFC rail to force softmute. 1 Reserved Always write 0. 0 1 0 0 0 USE_RSSI 0 Function When set, RSSI will be used instead of SNR as the ACF controlling metric. 0 = Use SNR as the controlling metric. 1 = Use RSSI as the controlling metric. USE_RSSI Property 0x2000 AM_VALID_MAX_TUNE_ERROR The AM_VALID_MAX_TUNE_ERROR property sets the maximum frequency error allowed in units of 2 ppm before setting the AFC rail indicator (AFCRL). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 75 (150 ppm) Si475x/5xC-A55, Default: 126 (252 ppm) Units: 2 ppm AM_VALID_MAX_TUNE_ERROR 15 14 13 12 11 10 9 8 7 0x00 0x00 6 5 4 3 2 1 0 AMMAXTUNEERR[7:0] 0x4B Rev. 0.9 241 AN543 Bit Name Function 15:8 Reserved 7:0 AMMAXTUNEERR [7:0] Always write 0. Sets the maximum freq error allowed in units of 2 ppm before setting the AFC rail indicator (AFCRL). Default is 75. Range is 0-126. Property 0x2001 AM_VALID_RSSI_TIME The AM_VALID_RSSI_TIME property sets the amount of time in milliseconds to allow the RSSI metric to settle before evaluating. For 4 MHz crystal operation, the minimum recommended settling time for RSSI is 8 milliseconds. The reliability of the valid bit for identifying valid stations relies on this parameter being set properly. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 5 Units: ms AM_VALID_RSSI_TIME 15 14 13 12 Bit Name 15:6 Reserved 5:0 11 10 9 8 7 6 5 4 3 2 0x00 RSSIVALTIME[5:0] 0x00 0x05 1 0 Function Always write to 0. Validation time in milliseconds. Default is 5 ms. Range is 5-63 ms in Si475x-A30 and earlier. Range is 5-127 ms in si475x-A40 and later. RSSIVALTIME[5:0] Note: The recommended minimum RSSI settling time is 8 ms. Property 0x2002 AM_VALID_SNR_TIME The AM_VALID_SNR_TIME property sets the amount of time in milliseconds to allow the RSSI metric to settle before evaluating. The minimum SNR settling delay is 27 milliseconds. The reliability of the valid bit for identifying valid stations relies on this parameter being set properly. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 36 Units: ms AM_VALID_SNR_TIME 15 242 14 13 12 11 10 9 8 7 6 5 4 3 2 0x00 SNRVALTIME [5:0] 0x00 0x24 Rev. 0.9 1 0 AN543 Bit Name Function 15:6 Reserved 5:0 SNRVALTIME[5:0] Always write to 0. Validation time in milliseconds. Default is 36 ms. Range is 0-63 ms. Range is 27-63 ms in Si475x-A30 and earlier. Range is 27-127 ms in si475x-A40 and later. Property 0x2003 AM_VALID_SNR_THRESHOLD The AM_VALID_SNR_THRESHOLD property sets the SNR threshold for a valid AM Seek/Tune. If the desired channel SNR is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 5 Units: dB AM_VALID_SNR_THRESHOLD 15 Bit 15:8 7:0 14 13 12 11 10 9 8 7 6 5 4 3 AMVALUSN[7:0] AMVALSNR[7:0] 0x00 0x05 2 1 0 Name Function AMVALUSN[7:0] (Available in Si475x-A40 only) AM Seek/Tune USN Threshold. Default: 0 Range: 0 to 127 - Specified in units of negative -dBFS. (0 is full scale, 127 is 127dB down from full scale.) 0 = USN is not used as a criterion in determining the validity of a station. (In Si475x-A30 and earlier, this field should be the continued SIGN of AMVALSNR. That is, it should be 0x00 for positive (+) values and 0xFF for negative (-) values.) AMVALSNR [7:0] Sets the SNR threshold for a valid AM Seek/Tune. Default is 5 dB. Range is -128 to 127 in steps of 1 dB. -128 = SNR is not used as a criterion in determining the validity of a station. Rev. 0.9 243 AN543 Property 0x2004 AM_VALID_RSSI_THRESHOLD The AM_VALID_RSSI_THRESHOLD property sets the RSSI threshold for a valid AM Seek/Tune. If the desired channel RSSI is above this threshold, then it is considered valid. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 10 Units: dBV AM_VALID_RSSI_THRESHOLD 15 14 13 12 10 9 8 7 6 5 4 3 0x00 AMVALRSSI[7:0] 0x00 0x0A Bit Name 15:8 Reserved 7:0 11 2 1 0 Function Write 0 for (+) values, 0xFF for (-) values. AMVALRSSI[7:0] Sets the RSSI threshold for a valid AM Seek/Tune. Default is 10 dBV. Range is -128 to 127 in steps of 1 dB. -128 = RSSI is not used as a criterion in determining the validity of a station. Property 0x200C AM_VALID_FREQOFF_SCALE The AM_VALID_FREQOFF_SCALE sets the units in Hz for the AM_RSQ_STATUS response FREQOFF metric, as well as AM_VALID_MAX_TUNE_ERROR. (For example, if AM_VALID_FREQOFF_SCALE is set to 100, then AM_VALID_MAX_TUNE_ERROR will have units of 100 Hz per property value step.) The default is to use units of binary ppm instead of any number of Hz. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. In Si475x-A30 and earlier, FREQOFF is always in units of bppm (binary ppm, or 2 ppm). Si475x-A30 and earlier: This property is not available. Si475x-A40 and later, Default: 0 Units: Hz AM_VALID_FREQOFF_SCALE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SCALE[15:0] 0x0000 Bit 15:0 244 Name Function SCALE[15:0] Sets the units in Hz for the frequency offset metric and the AM_VALID_MAX_TUNE_ERROR. The recommended value for AM is 50 Hz. Default is 0. 0 = Use units of bppm. Rev. 0.9 AN543 Property 0x200D AM_VALID_FREQOFF_FILTER The AM_VALID_FREQOFF_FILTER sets the number of FREQOFF samples averaged by the metric filter before reporting FREQOFF as part of AM_RSQ_STATUS. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A30 and earlier: This property is not available. Si475x-A40 and later, Default: 100 AM_VALID_RSSI_THRESHOLD 15 14 13 12 10 9 8 7 6 5 4 3 0x00 FILTER[7:0] 0x00 0x64 Bit Name 15:8 Reserved 7:0 11 2 1 0 Function Always write 0. The number of FREQOFF values that are averaged when reporting the value in AM_RSQ_STATUS. (Values below 10 will begin to track audio and are not recommended. If low-cut is being used then the minimum value will need to be increased accordingly to avoid tracking low frequency audio.) Default is 100 samples. Range is 0-127. FILTER[7:0] Property 0x2100 AM_NB_DETECT_THRESHOLD The AM_NB_DETECT_THRESHOLD property sets the threshold for detecting impulses in dB above the noise floor. The noise blanker can be disabled by setting the noise blanker detect threshold to 0.The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 18 Units: dB AM_NB_DETECT_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 DETECT_THRESHOLD[15:0] 0x0012 Bit 15:0 Name Function DETECT_THRESHOLD[15:0] Sets the threshold for detecting impulses in dB above the noise floor. Default is 18 dB. Range is 0-90 dB. To disable the noise blanker, set the DETECT_THRESHOLD to 0. Rev. 0.9 245 AN543 Property 0x2101 AM_NB_INTERVAL The AM_NB_INTERVAL property sets the interval in microseconds that original samples are replaced by interpolated clean samples. The noise blanker can be disabled by setting the noise blanker detect threshold to 0.The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 4 AM_NB_INTERVAL 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NB_INTERVAL[15:0] 0x0004 246 Bit Name Function 15:0 NB_INTERVAL[15:0] Sets the interval in number of audio samples that original samples are replaced by interpolated clean samples. Default is 4. Range is 1-40. Rev. 0.9 AN543 Property 0x2102 AM_ NB_DELAY The AM_NB_DELAY property sets the noise blanker delay in number of samples from where to select the good samples to replace the samples corrupted by the impulse. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be sent when in powerup mode. Si475x-A10, Default: 0x005D Si475x-A20, Default: 0x175D Si475x-A30, Default: 0x3AE8 AM_NB_DELAY 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0x0 SECONDARY_BLANKER_DELAY[5:0] PRIMARY_BLANKER_DELAY[7:0] 0x0 0x3A 0xE8 Bit Name 15:14 Reserved 0 Function Always write to 00. 13:8 Delay in units of number of samples from where to select the good samples to replace the samples corrupted by the impulse for the secondary blanker at 23k sample/second. (Available in Si475x-A20 and later only). SECONDARY_BLANKER_DELAY[5:0] Si475x-A20 Default is 23 (1 ms). Si475x-A30 and later, Default is 58 (2.5 ms). Range is 1-256. Sum of SECONDARY_BLANKER_DELAY, NB_INTERVAL, and DETECT_DELAY may not exceed 256. 7:0 Delay in units of number of samples from where to select the good samples to replace the samples corrupted by the impulse for the primary blanker at 93k sample/second. Si475x-A20 and earlier: Default is 93 (1 ms), Range: 1-63. Si475x-A30 and later: Default is 232 (2.5 ms), Range: 1-255. PRIMARY_BLANKER_DELAY[7:0] Rev. 0.9 247 AN543 Property 0x2103 AM_SECONDARY_NB_DETECT_THRESHOLD The AM_SECONDARY_NB_DETECT_THRESHOLD property sets the threshold for detecting impulses in dB above the noise floor. The noise blanker can be disabled by setting the noise blanker detect threshold to 0.This blanker is used in the presence of strong near end blockers. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Default: 21 Units: dB AM_SECONDARY_NB_DETECT_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SECONDARY_DETECT_THRESHOLD[15:0] 0x0015 Bit Name Function 15:0 SECONDARY_DETECT_ THRESHOLD[15:0] Sets the threshold for detecting impulses in dB above the noise floor. Default is 21 dB. Range is 0-90 dB. To disable the noise blanker, set the SECONDARY_DETECT_THRESHOLD to 0. Property 0x2104 AM_SECONDARY_NB_INTERVAL The AM_SECONDARY_NB_INTERVAL property sets the interval in microseconds that original samples are replaced by interpolated clean samples. The noise blanker can be disabled by setting the noise blanker detect threshold to 0. The secondary blanker is used in the presence of strong near end blockers. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This command may only be sent in powerup mode. Default: 4 AM_SECONDARY_NB_INTERVAL 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 SECONDARY_NB_INTERVAL[15:0] 0x0004 Bit 15:0 248 Name Function Sets the interval in microseconds that original samples are SECONDARY_NB_INTERVAL[15:0] replaced by interpolated clean samples Default if 4. Range is 0-25. Rev. 0.9 0 AN543 Property 0x2106 AM_NB_STRONG_SIGNAL_SHUTOFF The AM_NB_STRONG_SIGNAL_SHUTOFF property sets the RSSI thresholds for determining turn on/off the noise blanker. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be sent when in powerup mode. Note that this feature is off by default, but the recommended value when turned on is 0x322D. Si475x-A40 and earlier, not available. Si475x/5xC-A55, Default: 0x6070 AM_NB_STRONG_SIGNAL_SHUTOFF 15 14 13 12 11 10 9 8 7 6 5 4 3 2 XMAX [7:0] XMMIN [7:0] 0x60 0x70 Bit Name 15:8 XMAX [15:8] RSSI level above which the noise blanker is effectively off. Range is -127 to 127. 7:0 XMMIN [7:0] RSSI level below which the noise blanker is effectively on. Range is -127 to 127. 1 0 Function Property 0x2107 AM_NB_DETECT_DELAY The AM_NB_DETECT_DELAY property sets the number of samples to delay after detection of a noise pulse condition before applying impulse blanking. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be sent when in powerup mode. Si475x-A40 and earlier, Default: 8 Si475x/5xC-A55, Default: 5 AM_NB_DETECT_DELAY 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 DETECT_DELAY [15:0] 0x0008 Bit Name 15:0 DETECT_DELAY [15:0] Function Delay in units of number of samples before applying impulse blanking to the original samples.Range is 0-25. Rev. 0.9 249 AN543 Property 0x2108 AM_NB_SCHEME The AM_NB_SCHEME property selects the noise blanking scheme. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 is not available. Si475x-A20, Default: 0x0001 Si475x-A30, Default: 0x0000 Si475x-A40, Default: 0x0100 Si475x/5xC-A55, Default: 0x0101 AM_NB_SCHEME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 0 LEARNINGSTEP[6:0] 0x00 MODE[1:0] 0 0x01 0x00 0x0 Bit Name 15 Reserved 14:8 250 Function Always write to 0. (Available in Si475x-A40 only) I/Q Blanker learning step size. This controls the update speed of the LEARNINGSTEP[6:0] adaptive I/Q predictor. The higher the value the faster the convergence, but too fast could cause overshoot. Range: 1 to 127 7:2 Reserved 1:0 MODE[1:0] Always write to 0. Selects the noise blanking scheme. Default is 0. 0 = Sample/hold at IF. Delay determined by 0x2102 AM_NB_DELAY. 1 = Linear extrapolation at IF. Rev. 0.9 AN543 Property 0x2109 AM_NB_MODE_CONTROL The AM_NB_MODE_CONTROL property sets high-level control for the FM noise blanker. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0x0004 Si475x/5xC-A55, Default: 0x0002 AM_NB_MODE_CONTROL 15 14 13 12 11 Bit Name 15:3 Reserved 2:0 10 9 8 7 6 5 4 3 2 1 0x0000 MODE[2:0] 0x0000 0x4 0 Function MODE[2:0] Always write 0. Sets the mode for the I/Q noise blanker. 0 = wideband (93 kS/s) blanker. 1 = narrowband (23 kS/s) blanker with pre-channel filter. 2 = narrowband (23 kS/s) blanker without pre-channel filter. 4 = Automatic selection based on blocker levels. Property 0x2110 AM_NB_BURST_NOISE_DETECT_THRESHOLD The AM_NB_BURST_NOISE_DETECT_THRESHOLD sets the threshold for an additional AM noise blanker to detect and blank a longer "burst-style" noise profile to target the noise from a vehicle accessory electronic actuator motor. This additional noise blanking is in 93 kS/s I/Q signal and added to control the I/Q blanker. Enabling this feature may cause the noise blanker to engage too often, which may introduce audio artifacts. Unless the specific application environment includes longer, burst-style noise which is not mitigated by the other blankers, it is recommended to disable this property by setting it to 0x0000. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A30 and earlier, not available Si475x-A40, Default: 0x0609 Si475x/5xC-A55, Default: 0x0000 AM_NB_MODE_CONTROL 15 14 13 12 11 10 9 8 7 6 5 4 3 SAMPLE[7:0] THRESH[7:0] 0x00 0x00 Rev. 0.9 2 1 0 251 AN543 Bit Name Function 15:8 SAMPLE[7:0] Number of samples blanker at 93 kS/s due to longer bursts from automotive environment. Range 2~64. 7:0 THRESH[7:0] Sets the threshold for detecting longer bursts from automotive environment. Do not set lower than 7 dB. Property 0x2200 AM_CHBW_SQ_MIN_MAX The AM_CHBW_SQ_MIN_MAX property sets the maximum and minimum Channel Filter Bandwidth in units of 100 Hz based on max(IQSNR,SNR). To force a given Channel Filter Bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: Since the Si4750/51/52/53 do not support dynamic bandwidth control MIN[7:0] = MAX[7:0], MAX[7:0] determines the channel filter setting. Si475x-A20 and earlier, Default: 0x1414 Si475x-A30 and later, Default: 0x2314 Units: 100 Hz AM_CHBW_SQ_MIN_MAX 15 252 14 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x23 0x14 2 Bit Name Function 15:8 MAX [7:0] Sets the maximum Channel Filter Bandwidth in units of 100 Hz. Default is 3.5 kHz. Range is 15-100. 7:0 MIN [7:0] Sets the minimum Channel Filter Bandwidth in units of 100 Hz. Default is 2 kHz. Range is 15-100. Rev. 0.9 1 0 AN543 Property 0x2201 AM_CHBW_SQ_HIGH_THRESHOLD (Si4754/55/56/57 Only) The AM_CHBW_SQ_HIGH_THRESHOLD property sets the max(IQSNR,SNR) threshold for maximum Channel Filter Bandwidth. If the max(IQSNR,SNR) reported by the device is greater than the SQ High threshold programmed, then the Channel Filter Bandwidth will be set to the maximum value programmed through Property 0x2200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 30 Units: dB (for SNR), dBV (for RSSI) AM_CHBW_SQ_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SQMAX[15:0] 0x001E Bit 15:0 Name Function SQMAX[15:0] Sets the max(IQSNR,SNR)threshold for maximum Channel Filter Bandwidth. Default is 30 dB. Range is -128 to 127 dB (or dBV for RSSI). Property 0x2202 AM_CHBW_SQ_LOW_THRESHOLD (Si4754/55/56/57 Only) The AM_CHBW_SQ_LOW_THRESHOLD property sets the max(IQSNR,SNR) threshold for minimum Channel Filter Bandwidth. If the max(IQSNR,SNR) reported by the device is less than the SQ Low threshold programmed, then the Channel Filter Bandwidth will be set to the minimum value programmed through Property 0x2200. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 15 Units: dB AM_CHBW_SQ_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 SQMIN[15:0] 0x000F Bit 15:0 Name Function SQMIN[15:0] Sets the max(IQSNR,SNR) threshold for minimum Channel Filter Bandwidth. Default is 15 dB. Range is -128 to 127 dB Rev. 0.9 253 AN543 Property 0x2203 AM_CHBW_SQ_WIDENING_TIME (Si4754/55/56/57 Only) The AM_CHBW_SQ_WIDENING_TIME property sets the Channel Filter Bandwidth widening time based on max(IQSNR,SNR). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 2048 Units: ms AM_CHBW_SQ_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0800 Bit Name Function 15:0 WIDENING_TIME[15:0] Sets the max(IQSNR,SNR) based Channel Filter Bandwidth widening time. Default is 2048 ms. Range is 1-32767 ms. Property 0x2204 AM_CHBW_SQ_NARROWING_TIME (Si4754/55/56/57 Only) The AM_CHBW_SQ_NARROWING_TIME property sets the Channel Filter Bandwidth narrowing time based on max(IQSNR,SNR). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 16 Units: ms AM_CHBW_SQ_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0010 Bit 15:0 Name Function NARROWING_TIME [15:0] Sets the max(IQSNR,SNR) based Channel Filter Bandwidth narrowing time. Default is 16 ms. Range is 1-32767 ms. 254 Rev. 0.9 AN543 Property 0x2205 AM_CHBW_ASSI_MIN_MAX (Si4754/55/56/57 Only) The AM_CHBW_ASSI_MIN_MAX property sets the maximum and minimum Channel Filter Bandwidth in units of 100 Hz. Based on adjacent signal strength indicator (ASSI.) To force a given Channel Filter Bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: Si4750/51/52/53 do not support dynamic bandwidth control, but MIN[7:0] = MAX[7:0] can determine the channel filter setting. Si475x-A10 is not available. Si475x-A20 and later, Default: 0x3232. Units: 100 Hz AM_CHBW_ASSI_MIN_MAX 15 14 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x32 0x32 2 1 0 Bit Name Function 15:8 MAX[7:0] Sets the maximum Channel Filter Bandwidth in units of 100 Hz. Default is 5 kHz. Range is 15-100. 7:0 MIN[7:0] Sets the minimum Channel Filter Bandwidth in units of 100 Hz. Default is 5 kHz. Range is 15-100. Rev. 0.9 255 AN543 Property 0x2206 AM_CHBW_ASSI_LOW_THRESHOLD (Si4754/55/56/57 Only) The AM_CHBW_ASSI_LOW_THRESHOLD property sets the ASSI threshold in dB for maximum Channel Filter Bandwidth. ASSI is calculated as the worse (higher) value between HASSI and LASSI. If the ASSI reported by the device is less than the ASSI Low threshold programmed, then the Channel Filter Bandwidth will be set to the maximum value programmed through Property 0x2205. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 is not available. Si475x-A20 and later, Default: 10 Units: dB AM_CHBW_ASSI_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ASSIMIN[15:0] 0x000A Bit Name Function 15:0 ASSIMIN[15:0] Sets the ASSI threshold for maximum Channel Filter Bandwidth. Default is 10 dB. Range is -128 to 127 dB. Property 0x2207 AM_CHBW_ASSI_HIGH_THRESHOLD (Si4754/55/56/57 Only) The AM_CHBW_ASSI_HIGH_THRESHOLD property sets the ASSI threshold in dB for minimum Channel Filter Bandwidth. ASSI is calculated as the worse (higher) value between HASSI and LASSI. If the ASSI reported by the device is greater than the ASSI High threshold programmed, then the Channel Filter Bandwidth will be set to the minimum value programmed through Property 0x2205. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 is not available. Si475x-A20 and later, Default: 30 Units: dB AM_CHBW_ASSI_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 ASSIMAX[15:0] 0x001E 256 Bit Name 15:0 ASSIMAX[15:0] Function Sets the ASSI threshold for minimum Channel Filter Bandwidth. Default is 30 dB. Range is -128 to 127 dB. Rev. 0.9 1 0 AN543 Property 0x2208 AM_CHBW_ASSI_WIDENING_TIME (Si4754/55/56/57 Only) The AM_CHBW_ASSI_WIDENING_TIME property sets the Channel Filter Bandwidth widening time based on ASSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 is not available. Si475x-A20 and later, Default: 16 Units: ms AM_CHBW_ASSI_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0010 Bit Name Function 15:0 WIDENING_TIME[15:0] Sets the channel filter widening time in ms. Default is 16 ms. Range is 1-32767 ms. Property 0x2209 AM_CHBW_ASSI_NARROWING_TIME (Si4754/55/56/57 Only) The AM_CHBW_ASSI_NARROWING_TIME property sets the Channel Filter Bandwidth narrowing time based on ASSI. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A10 is not available. Si475x-A20 and later, Default: 16 Units: ms AM_CHBW_ASSI_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0010 Bit Name 15:0 NARROWING_TIME[15:0] Function Sets the channel filter narrowing time in ms. Default is 16 ms. Range is 1-32767 ms. Rev. 0.9 257 AN543 Property 0x220A AM_CHBW_RQ_MIN_MAX The AM_CHBW_RQ_MIN_MAX property sets the RSSI maximum and minimum channel bandwidth in the unit of 100 Hz. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier is not available. Si475x/5xC-A55, Default: 0x2314 Units: 100 Hz AM_CHBW_RQ_MIN_MAX 15 14 13 12 11 10 9 8 7 6 5 4 3 MAX [7:0] MIN [7:0] 0x23 0x14 Bit Name 15:8 MAX [7:0] Sets the maximum channel bandwidth in 100 kHz. Default is 35. Range is 15 ~ 100. 7:0 MIN[7:0] Sets the minimum channel bandwidth in 100 kHz. Default is 20. Range is 15 ~ 100. 2 1 0 Function Property 0x220B AM_CHBW_RQ_LOW_THRESHOLD The AM_CHBW_RQ_LOW_THRESHOLD property sets the RSSI threshold for minimum channel bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier is not available. Si475x/5xC-A55, Default: 15 Units: 100 Hz AM_CHBW_RQ_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 RQMIN [15:0] 0x000F Bit Name 15:0 RQMIN[15:0] 258 Function Sets the RSSI threshold for minimum channel bandwidth. Default is 15 dBV. Rev. 0.9 1 0 AN543 Property 0x220C AM_CHBW_RQ_HIGH_THRESHOLD The AM_CHBW_RQ_HIGH_THRESHOLD property sets the RSSI threshold for maximum channel filter bandwidth. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier is not available. Si475x/5xC-A55, Default: 30 Units: dBV AM_CHBW_RQ_HIGH_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RQMAX[15:0] 0x001E Bit Name Function 15:0 RQMAX[15:0] Sets the RSSI threshold for maximum channel bandwidth. Default is 30 dBV. Property 0x220D AM_CHBW_RQ_WIDENING_TIME The AM_CHBW_RQ_WIDENING_TIME property sets the RSSI based channel filter bandwidth widening time. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier is not available. Si475x/5xC-A55, Default: 2048 Units: ms AM_CHBW_RQ_WIDENING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WIDENING_TIME[15:0] 0x0800 Bit Name 15:0 WIDENING_TIME[15:0] Function Sets the RSSI based channel filter bandwidth widening time. Default is 2048 ms. Rev. 0.9 259 AN543 Property 0x220E AM_CHBW_RQ_NARROWING_TIME The AM_CHBW_RQ_NARROWING_TIME property sets the RSSI based channel filter bandwidth narrowing time. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier is not available. Si475x/5xC-A55, Default: 16 AM_CHBW_RQ_NARROWING_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 NARROWING_TIME[15:0] 0x0010 Bit Name Function 15:0 NARROWING_TIME[15:0] Sets the RSSI based channel filter bandwidth narrowing time. Default is 16 ms. Property 0x2300 AM_DEMOD_MODE The AM_DEMOD_MODE property selects the demodulation technique. To force to envelope demodulation, set this property to 0x0100. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier, Default: 0x0001 Si475x/5xC-A55, Default: 0x0100 AM_DEMOD_MODE 15 260 14 13 12 11 9 8 0x00 IQSNR FIXED_MODE 0x00 MODE[2:0] 0x00 0 1 0x00 0x0 Bit Name 15:10 Reserved 10 7 6 5 4 3 2 1 0 Function Always write to 0. 9 IQSNR (Available in Si475x-A40 and A55 only) When set, enables the I/Q SNR metric, which is more robust when AM carrier varied greatly (as with AM-SS). 0 = Normal SNR metric 1 = Enable AM-SS resistant SNR metric. This should only be used with envelope demodulation. 8 FIXED_MODE 0 = The demodulation technique is not fixed. 1 = The demodulation technique is fixed and will not automatically switch. Rev. 0.9 AN543 7:3 Reserved Always write to 0. 2:0 MODE[2:0] 0 = Envelope demodulation 1 = Coherent demodulation 2 = Envelope demodulation with carrier enhancement. Property 0x2301 AM_DEMOD_AFC_RANGE The AM_DEMOD_AFC_RANGE property specifies the range of AFC in Hz to allow for wideband AM. Envelope demod (property 0x2300) should be forced when this property is non-zero. The part must be retuned after modifying this property before it takes effect. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This property is not available Si475x-A30 and later, Default: 0 Units: Hz AM_DEMOD_AFC_RANGE 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RANGE[15:0] 0X0000 Bit Name Function 15:0 RANGE[15:0] Specify the range of AFC. If set to 0, range is determined by AM_VALID_MAX_TUNE_ERROR. Default is 0. Range is 0-6000 Hz. Property 0x2302 AM_DEMOD_CARRIER_ENH The AM_DEMOD_CARRIER_ENH property configures the envelope demodulation with carrier enhancement demodulator mode. Carrier enhancement has been found to reduce audio distortion while maintaining the robust reception benefits of envelope demodulation. This mode is selected by setting API property AM_DEMOD_MODE field MODE[2:0] to 2. This property only has an effect when API property AM_DEMOD_MODE field MODE[2:0] is set to 2. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A40 and earlier; this property is not available. Si475x/5xC-A55; Default: 20 Units: % AM_DEMOD_CARRIER_ENH 15 14 13 12 11 10 9 8 7 6 5 4 3 0x000 RATIO[6:0] 0x000 0x14 Rev. 0.9 2 1 0 261 AN543 Bit Name Function 15:7 Reserved 6:0 RATIO[6:0] Always write 0. Sets amount of carrier enhancement. Default is 20%, recommended range is 0 ~ 50%. Range is 0 to 100%. Property 0x3100 AM_HICUT_SQ_HIGH_THRESHOLD The AM_HICUT_SQ_HIGH_THRESHOLD property sets the SNR or RSSI level at which HICUT begins to band limit. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 8 Units: dB (for SNR), dBV (for RSSI) AM_HICUT_SQ_HIGH_THRESHOLD 15 262 14 13 12 11 10 9 8 7 6 5 4 3 2 0x000 SQ_HIGH[6:0] 0x000 0x08 Bit Name 15:7 Reserved 6:0 SQ_HIGH[6:0] 1 0 Function Always write 0. Sets the SNR or RSSI level at which HICUT begins to band limit. Default is 8. Range is from -127 to 127 dB (for SNR), dBV (for RSSI). Rev. 0.9 AN543 Property 0x3101 AM_HICUT_SQ_LOW_THRESHOLD The AM_HICUT_SQ_LOW_THRESHOLD property sets the SNR or RSSI level at which HICUT reaches maximum band limiting. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0 Units: dB AM_HICUT_SQ_LOW_THRESHOLD 15 14 13 12 11 10 9 8 7 6 5 4 3 2 0x000 SQ_LOW[6:0] 0x000 0x08 Bit Name 15:7 Reserved 6:0 SQ_LOW[6:0] 1 0 Function Always write 0. Sets the SNR or RSSI level at which HICUT reaches maximum band limiting. Default is 0. Range is from -127 to 127 dB (for SNR), dBV (for RSSI). Property 0x3102 AM_HICUT_ATTACK_TIME The AM_HICUT_ATTACK_TIME property sets the transition time in ms for which high cut lowers the cutoff frequency. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 16 Units: ms AM_HICUT_ATTACK_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 ATTACK[15:0] 0x0010 Bit Name 15:0 ATTACK[15:0] Function Sets the transition time in ms for which high cut lowers the cutoff frequency. Default is 16 ms. Range is 1-32767 ms. Rev. 0.9 263 AN543 Property 0x3103 AM_HICUT_RELEASE_TIME The AM_HICUT_RELEASE_TIME property sets the transition time in ms for which high cut increases the cutoff frequency. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 2000 Units: ms AM_HICUT_RELEASE_TIME 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 RELEASE[15:0] 0x07D0 Bit Name Function 15:0 RELEASE[15:0] Sets the transition time in ms for which high cut increases the cutoff frequency. Default is 2000 ms. Range is 1-32767 ms. Property 0x3104 AM_HICUT_CUTOFF_FREQ The AM_HICUT_CUTOFF_FREQ property sets the maximum and minimum HICUT transition frequencies in units of 100 Hz. To force a given HICUT filter bandwidth, set the min and max to the same value. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Default: 0x280A Units: 100 Hz AM_HICUT_CUTOFF_FREQ 15 264 14 13 12 11 10 9 8 7 6 5 4 3 MAX[7:0] MIN[7:0] 0x28 0x0A Bit Name Function 15:8 MAX [7:0] Maximum HICUT transition frequency in units of 100 Hz. Default is 4 kHz. Range is 10-50. 7:0 MIN [7:0] Minimum HICUT transition frequency in units of 100 Hz. Default is 1 kHz. Range is 10-50. Rev. 0.9 2 1 0 AN543 Property 0x3105 AM_LOWCUT_MIN_FREQ The AM_LOWCUT_MIN_FREQ property sets the minimum cutoff frequency. The LowCut tracks the HICUT engine; therefore, thresholds are programmed in property 0x3100 and 0x3101. Setting the property to 0 disables LowCut. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Note: Once set, this property may not be observed until after the next AM_TUNE_FREQ command is issued. Si475x-A20 and earlier: This feature is not available. Do not write to this property. Si475x-A30 and later, Default: 0 Units: Hz AM_LOWCUT_MIN_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 FREQ_MIN[15:0] 0x0000 Bit Name 15:0 Function FREQ_MIN[15:0] Sets the minimum LOW-CUT cutoff frequency in Hz. Default is disabled. Range is 0 (disable) or 8-1000 Hz. 0 = Disabled. Property 0x3106 AM_LOWCUT_MAX_FREQ The AM_LOWCUT_MAX_FREQ property sets the maximum cutoff frequency. The LowCut tracks the HICUT engine, therefore thresholds are programmed in property 0x3100 and 0x3101. The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read in powerup mode. Si475x-A20 and earlier: This feature is not available. Do not write to this property. Si475x-A30 and later, Default: 0 Units: Hz AM_LOWCUT_MAX_FREQ 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 FREQ_MAX[15:0] 0x0000 Bit 15:0 Name Function FREQ_MAX[15:0] Sets the maximum LOW-CUT cutoff frequency in Hz. Note that if property 0x3105 (AM_LOWCUT_MIN_FREQ) is greater than 7, this property must be set to a value no less than property 0x3105. Default is 0 Hz. Range is 0- 1000 Hz. Rev. 0.9 265 AN543 section "7. Commands and Properties"for detailed descriptions of commands and properties. 8. Programming Examples 8.1. Configuration The following tables summarize the available configuration options for FM and AM functions. Refer to Table 15. FM Configuration Commands and Properties Pin Configuration Commands Properties Interrupts 0x1C 0x0000 Analog/MPX audio 0x1B RF/Audio Configuration Commands Properties Softmute 0x0400 RF Signal routing, AGC thresholds and timing 0x0700 Channel spacing 0x1100 RSQ (RSSI, SNR) Interrupts 0x1200 ACF (Softmute, Channel Filter Bandwidth, HIBLEND, HICUT) Interrupts 0x1300 Tune/seek metric thresholds and timing (RSSI, SNR, ISSI, ASSI, frequency error) 0x2000 Noise blankers 0x2100 Channel Filter Bandwidth (RSSI, STRONGDEV, ASSI, ASSI200, ASSI200DEV, ASSI100 B) range and timing 0x2200 Pop filter 0x3200 Blend (RSSI/SNR, Multi-path, USN) range and timing 0x3500 HICUT (RSSI/SNR, Multi-path, USN) range and timing 0x3600 HIBLEND (RSSI/SNR, Multi-path, USN) range and timing 0x3700 RDS Configuration Commands RDS Interrupts, FIFO size and management, decoder configuration (Si4751/53/55/57 only). 266 Rev. 0.9 Properties 0x4000 AN543 Table 16. AM Configuration Commands and Properties Pin Configuration Commands Properties Interrupts 0x1C 0x0000 Analog audio 0x1B RF/Audio Configuration Commands Properties Power line filtering 0x0300 Softmute 0x0400 AVC (automatic volume control) 0x0500 RF Signal routing, AGC thresholds and timing 0x0700 Channel spacing 0x1100 RSQ (RSSI, SNR) Interrupts 0x1200 ACF (Softmute, Channel Filter Bandwidth, HICUT) Interrupts 0x1300 Tune/seek metric thresholds and timing (RSSI, SNR, ISSI, ASSI frequency error) 0x2000 Noise blankers 0x2100 Channel Filter Bandwidth (RSSI, SNR, ASSI) range and timing 0x2200 HICUT (RSSI/SNR) range and timing 0x3100 8.1.1. Analog/MPX Audio (MPX Si4755/57 Only) Analog and MPX audio setup includes pin configuration. 1. Complete steps up to and including 5 in section "5.1. Powerup Receiver from Internal Memory" on page 4 or 10 in "5.2. Powerup Receiver from a Patch" on page 7. 2. Send the ANA_AUDIO_PIN_CFG command to route analog left and right channel to LOUT/ROUT pins, or to route the MPX to the LOUT pin. This step may be omitted if analog audio is not required. Example: ANA_AUDIO_PIN_CFG Command Action Data Description CMD 0x1B ANA_AUDIO_PIN_CFG ARG1 0x02 2 = LOUT/ROUT pins configured to output audio. STATUS 0x80 Rev. 0.9 267 AN543 8.1.2. AGC For FM and AM modes, the AGC default configuration is generally optimal. The following section describes the settings and options. AGC settings may be over-ridden by setting property 0x0710 FM_AGC_OVERRIDE (or similar property 0x0710 AM_AGC_OVERRIDE) and the state of the AGC peak detectors may be monitored by sending command 0x17 AGC_STATUS (or similar property 0x17 AM_AGC_STATUS). 8.1.2.1. FM FM AGC configuration involves setting signal routing, AGC and peak detector. The default property settings are configured for routing through the LNA input (instead of directly to the mixer) with 50 LNA impedance as shown in Figure 8. FMAGC2 FMAGC1 FMXI RF Pkd RFREG Reg RL FMO LNA 50 FMI to AM RF Pkd Si475x Figure 8. FM Single Receiver System Diagram Note: For primary/companion configuration in which two receivers are connected to the same antenna, the LNA input impedance should be set to 100 as shown in Figure 9. 268 Rev. 0.9 AN543 FMAGC2 FMAGC1 FMXI RF Pkd RFREG Reg RL LNA FMO 50 100 FMI RF Pkd to AM Si475x FMXIP RF Pkd FMXIN RFREG Reg RL FMO 100 FMI LNA RF Pkd Si4769 Figure 9. Primary and Companion Receiver System Diagram For optimal weak signal, blocker and intermodulation performance, the default property settings are configured to disable the LNA peak detector and associated attack/release time constants, and enable the mixer peak detector thresholds to 85 dBV and 3 dB hysteresis, with an attack time of 4 ms and release time of 80 ms. To improve weak signal performance at the expense of intermodulation performance, the mixer peak detector thresholds may be increased to as high as 93 dBV. To improve blocker and intermodulation performance at the expense of weak signal performance, the mixer peak detector thresholds may be decreased to as low as 79 dBV. To improve impulsive noise desensitization (caused by engaging the AGC) at the expense of AGC response time, the mixer peak detector attack time may be increased from 4 ms to an attack time greater than the period of the impulses. 8.1.2.2. AM AM AGC configuration involves configuring signal routing, AGC and peak detector characteristics. The default property settings are configured for optimal performance with the harmonic rejection enabled, IF AGC attack time of 80 ms and release time of 804 ms, RF attack time of 8 ms and RF release time of 800 ms. Rev. 0.9 269 AN543 8.1.3. Interrupts The interrupt status can be monitored by sending command 0x15 GET_INT_STATUS. Note that the command response varies based on FM or AM mode. Interrupt pins can be configured by sending command 0x1C INTB_PIN_CFG. Property 0x0000 INT_CTL_ENABLE enables top-level interrupt sources and interrupt repetition characteristics. Property group 0x1200 configures RSQ (RSSI, SNR) interrupts. Property group 0x1300 configures ACF (Softmute, Channel Filter Bandwidth, HIBLEND, HICUT) interrupts. Note that HIBLEND only applies to FM mode operation. Property group 0x4000 configures RDS interrupts. 8.1.4. Noise Blankers 8.1.4.1. FM Property group 0x2100 configures the noise blankers for FM mode. The FM noise blanking system consists of a detector and audio sample blanker after the FM demodulator. The detector compares average USN with USN scaled by the FM_NB_DETECT_THRESHOLD property setting. If the scaled USN is greater than the filtered USN audio samples will be blanked. Lower values of FM_NB_DETECT_THRESHOLD result in more aggressive noise blanking. For weak signal levels, the USN of only the L+R portion of the MPX spectrum is used as the detector input. For higher signal levels, the USN of the entire MPX spectrum is used as the detector input. The signal levels at which the switch between weak/strong blanking occurs is set by the FM_NB_STRONG_WEAK_SWITCH property (by default, SNR < 9 dB for weak signal blanking and SNR >11 dB for strong signal blanking). For strong signal levels (RSSI > 50 dBV) the noise blanker is disabled as configured by FM_NB_STRONG_SIGNAL_SHUTOFF. The number of samples to blank is set by the FM_NB_INTERVAL property setting. Higher values result in more aggressive noise blanking, as more samples are replaced with repaired ones. 8.1.4.2. AM Property group 0x2100 configures the noise blankers for AM modes. The AM noise blanking system consists of a wide band detector and I/Q sample blanker before the first channel filter and a narrow band detector and I/Q sample blanker after the first channel filter. The detectors compare average USN with USN scaled by the AM_NB_DETECT_THRESHOLD (wide band) and AM_SECONDARY_NB_DETECT_THRESHOLD (narrow band) property setting. If the scaled USN is greater than the filtered USN audio samples will be blanked. Lower values of AM_NB_DETECT_THRESHOLD or AM_SECONDARY_NB_DETECT_THRESHOLD result in more aggressive noise blanking. The narrow band noise blanker with pre-channel filter is enabled if 1 channel adjacent blocker is detected. In this mode, the wide band detector AM_NB_DETECT_THRESHOLD is used. The narrow band noise blanker without pre-channel filter is enabled if 2 or 3 channel adjacent blocker is detected. In this mode, the narrow band detector AM_SECONDARY_NB_DETECT_THRESHOLD is used. The wide band noise blanker is enabled if no adjacent blocker is detected. In this mode, the wide band detector AM_NB_DETECT_THRESHOLD is used. 8.1.5. Pop Filter Property group 0x3200 configures the pop filter for FM mode operation. Two independent pop filter engines can be configured for minimum and maximum limiting of the MPX using RSSI and USN as the metric. Limiting ranging from minimum to maximum occurs at the specified attack rate as the RSSI or USN metric increases above the minimum threshold and reaches the maximum threshold. Limiting ranging from maximum to minimum occurs at the specified release rate as the RSSI or USN metric decreases below the maximum threshold and reaches the minimum threshold. The resulting limiting level is the maximum of the result of the two pop filter engines. Refer to Figure 10. 270 Rev. 0.9 AN543 Max Limiting Min Min RSSI or USN Max Figure 10. Pop Filter Thresholds 8.1.6. Channel Filter Bandwidth 8.1.6.1. FM Property group 0x2200 configures Channel Filter Bandwidth characteristics for FM mode. Six independent Channel Filter Bandwidth engines can be configured using RSSI/deviation (weak signal engine), ASSI100 (absolute value of difference between 100 kHz channel RSSI), ASSI200 (sum of 200 kHz channel RSSI minus desired channel RSSI), strong signal deviation, 200 kHz blocker deviation and strong 100 kHz blocker as the metric. For RSSI, ASSI100, ASSI200 and strong signal deviation, Channel Filter Bandwidth ranging from minimum to maximum occurs at the specified widening rate as the metric increases above the minimum threshold and reaches maximum threshold. Channel Filter Bandwidth ranging from maximum to minimum occurs at the specified narrowing rate as the metric decreases below the maximum threshold and reaches the minimum threshold. For 200 kHz blocker deviation, Channel Filter Bandwidth ranging from 80 to 32 kHz occurs at 1 ms rate as the metric increases above 75 kHz and reaches 100 kHz. Channel Filter Bandwidth ranging from 32 to 80 kHz occurs at the 300 ms rate as the metric decreases below 100 kHz and reaches 75 kHz. The resulting Channel Filter Bandwidth is the minimum of the result of the six blend engine calculations. Property 0x1306 FM_ACF_CONTROL_SOURCE is used to select RSSI or deviation as a metric for the weak signal engine. The default condition is RSSI. Property 0x220F FM_CHBW_WEAKSIG_THR is used to set the hysteresis window for enabling the weak signal RSSI/deviation engine. The default is to enable above 16 dBuV RSSI and disable below 14 dBV RSSI. Note that this hysteresis range is always determined by RSSI and is not configurable with the FM_ACF_CONTROL_SOURCE property. Property 0x2210 FM_CHBW_BLOCKER_THR is used to set the hysteresis window for engaging the 200 kHz blocker engine. The default is to enable above 20 dB ASSI200 and disable below 10 dB ASSI200. Note that 2 dB ASSI200 indicates that the sum of the energy at +200 kHz and -200 kHz is 20 dB greater than the desired channel. The 200 kHz blocker deviation engine is only enabled when sufficient pilot energy is present on the desired channel. Rev. 0.9 271 AN543 8.1.6.2. AM Property group 0x2200 configures Channel Filter Bandwidth characteristics for AM. Two independent Channel Filter Bandwidth engines can be configured using RSSI or SNR and ASSI (independent 9/10 kHz channel RSSI relative to on-channel RSSI). Channel Filter Bandwidth ranging from minimum to maximum occurs at the specified widening rate as the metric increases above the minimum threshold and reaches maximum threshold. Channel Filter Bandwidth ranging from maximum to minimum occurs at the specified narrowing rate as the metric decreases below the maximum threshold and reaches the minimum threshold. The resulting Channel Filter Bandwidth is the minimum of the result of the two blend engine calculations. Property 0x1306 AM_ACF_CONTROL_SOURCE is used to select RSSI or SNR as a metric for the Channel Filter Bandwidth. 8.1.7. Softmute Property group 0x0400 configures softmute characteristics for FM and AM. Property 0x1306 FM_ACF_CONTROL_SOURCE (and AM_ACF_CONTROL_SOURCE) is used to select SNR (default) or RSSI as a metric for the softmute engine. For FM and AM modes, the property is also used to select whether an AFC rail condition will engage softmute. The most common cause for an AFC rail condition is tuning to an idle channel. Softmute engages as SNR (or RSSI) drops below a trigger threshold and audio level reaches a maximum attenuation at the end threshold. Softmute releases as SNR (or RSSI) rises above the end threshold and audio level reaches full level at the trigger threshold. The attack and release rates are configurable along with maximum attenuation and trigger and end thresholds. 8.1.8. Automatic Volume Control (AVC) Property group 0x0500 configures automatic volume control (AVC) for AM. The AVC minimum and maximum gain can be configured. The AVC maintains a constant carrier level. 8.1.9. Mono/stereo Blend Property group 0x3500 configures the mono/stereo blend characteristics for FM mode. Six independent blend engines can be configured using RSSI, multipath, and USN as the metric. Blend from minimum stereo to maximum stereo separation occurs at the specified attack rate as the metric increases above the minimum threshold and reaches maximum threshold. Blend from maximum stereo to minimum stereo separation occurs at the specified release rate as the metric decreases below the maximum threshold and reaches the minimum threshold. The resulting stereo separation is the minimum of the result of the six blend engine calculations. 8.1.10. HICUT HICUT applies a lowpass filter to the L+R MPX audio. 8.1.10.1. FM Property group 0x3600 configures the HICUT characteristics for FM mode. Six independent blend engines can be configured using RSSI, multipath, and USN as the metric. HICUT from minimum to maximum occurs at the specified attack rate as the metric increases above the minimum threshold and reaches maximum threshold. HICUT from maximum to minimum occurs at the specified release rate as the metric decreases below the maximum threshold and reaches the minimum threshold. The resulting HICUT is the minimum of the result of the six blend engine calculations. 272 Rev. 0.9 AN543 8.1.10.2. AM Property group 0x3100 configures the HICUT characteristics for AM mode. The blend engine can be configured with RSSI or SNR as the metric. HICUT from minimum to maximum occurs at the specified attack rate as the metric increases above the minimum threshold and reaches maximum threshold. HICUT from maximum to minimum occurs at the specified release rate as the metric decreases below the maximum threshold and reaches the minimum threshold. 8.1.11. HIBLEND HIBLEND applies a lowpass filter to the L-R MPX audio. Property group 0x3700 configures the HIBLEND characteristics for FM mode. Six independent blend engines can be configured using RSSI, multipath, and USN as the metric. HIBLEND from minimum to maximum occurs at the specified attack rate as the metric increases above the minimum threshold and reaches maximum threshold. HIBLEND from maximum to minimum occurs at the specified release rate as the metric decreases below the maximum threshold and reaches the minimum threshold. The resulting HIBLEND is the minimum of the result of the six blend engine calculations. 8.1.12. Calibrating Crystal Loading Capacitance (XCLOAD) Tuning accuracy depends on accurate clocking from an external clock or the internal crystal oscillator. When the internal crystal oscillator is used, it is important to determine the optimum load capacitance of the crystal in order to minimize tuning error. This value is provided to the chip at power-up through the POWER_UP command's XCLOAD parameter. This procedure describes to how to determine the optimum value of XCLOAD. This procedure needs to be done once on a typical PCB for your application in order to determine a single value of XCLOAD which can work across as many devices as possible. 1. We will begin with and XCLOAD value of 0x1F, the middle value for the parameter. 2. Power up the device in FM mode with a POWER_UP command (as described in Section 5 Powerup and Powerdown) with the chosen value for the XCLOAD parameter. 3. Using a calibrated bench source, input an unmodulated, 98 MHz, 60 dBV signal to the part. 4. Tune the part to 98 MHz 5. Issue an FM_RSQ_STATUS command, and note the value of the frequency offset (FreqOff) returned by that command. 6. If FreqOff is greater than 0, decrease the value of XCLOAD downward. If FreqOff is less than 0, increase the value of CXLOAD. 7. Repeat steps 2 through 5 until FreqOff is 0 bppm. 8. Repeat the measurement described in steps 2 through 5 at 85 C, and again at -40 C. 9. If the value of FreqOff at 85 C or -40 C exceeds the crystal frequency accuracy specification for the tuner, you can attempt to adjust XCLOAD to bring the system back into specification. If FreqOff is positive and exceeds crystal frequency accuracy specifications, decrease the value of XCLOAD. If FreqOff is negative and exceeds crystal frequency accuracy specifications, increase the value of XCLOAD. 10.Repeat steps 2 through 9 across as many PCBs and crystals for your application as are necessary to account for part-to-part variation. 11. In production, we recommend you average XCLOAD across all such samples to determine an optimal value of XCLOAD for your application. Rev. 0.9 273 AN543 8.2. Operation Operations including sending a command, checking CTS and ERR state, checking STC state, tune, seek, and RDS are possible. 8.2.1. Tune The tune operation provides options for configuring tuning mode (validated normal tune, unvalidated fast tune, validated AF Tune, or validated AF Check) and audio filter state management (re-initialize based on new channel, or smoothly transition from current to new channel). In the case of tuning mode, 0x2000 property group sets the tune/seek metric thresholds and timing (RSSI, SNR, frequency error). Note that references to "AFC Rail" in this manual refers to a condition in which the frequency offset of the desired channel is outside the frequency error as configured with property group 0x2000. Start 1. Configure Tune parameters 2. FM_TUNE_FREQ or AM_TUNE_FREQ 3. Check CTS & ERR 4. Check STC End 274 Rev. 0.9 AN543 1. Complete the appropriate steps in section"8.1. Configuration". 2. Send the FM_TUNE_FREQ command to tune to a specific frequency. If the receiver has been muted, set property 0x0301 to disable mute. If using AF check, set the SMOOTHMETRICS bit to transition audio state from previous channel. Note that AM tuning is very similar. Refer to the AM_TUNE_FREQ command. Example: FM_TUNE_FREQ Command Action Data Description CMD 0x30 FM_TUNE_FREQ ARG1 0x00 Unconditionally stay on channel, initialize audio state based on new channel. ARG2 0x27 0x27A6 = tune to 101.50 MHz. ARG3 0xA6 STATUS 0x80 CTS = 1 3. Check the CTS and ERR state to determine whether it is safe to send the next command. Refer to section "8.2.4. Check CTS and ERR Status". 4. Check the STC state to determine tune status. Refer to section xxx Check STC state. 5. Repeat steps 2, 3, and 4 as necessary. Rev. 0.9 275 AN543 8.2.2. Seek Start 1/2/3. Configure Seek parameters 4. FM_SEEK_START or AM_SEEK_START 5. Check CTS and ERR 6. Check STC End 1. Complete the appropriate steps in section "8.1. Configuration". 2. Set the 0x1100 property group to configure the seek start, stop and channel spacing. 3. Set the 0x2000 property group to set the tune/seek metric thresholds and timing (RSSI, SNR, frequency error). Note that because every system will have unique signal gain and noise characteristics, RSSI and SNR thresholds should be carefully evaluated. 4. Send the FM_SEEK_START command to begin the seek operation. Example: FM_SEEK_START Command Action Data Description CMD 0x30 FM_SEEK_START ARG1 0x08 Seek up, don't wrap at the top of the band. STATUS 0x80 CTS = 1 5. Check the CTS and ERR state to determine whether it is safe to send the next command. Refer to section "8.2.4. Check CTS and ERR Status". 6. Check the STC state to determine seek status and abort if desired. Refer to Check STC state. 7. Repeat steps 4, 5, and 6 as necessary. 276 Rev. 0.9 AN543 8.2.3. RDS (Si4751/53/55/57 Only) 1. Complete the appropriate steps in section "8.1. Configuration"and section "8.2.1. Tune". 2. Set the 0x4000 property group to configure RDS Interrupts, FIFO size and management, and decoder configuration. 3. (Optional) Send the FM_RDS_BLOCKCOUNT command to verify RDS block error rate. The block error rate is defined as BLER = (UNCORRECTABLE + (EXPECTED-RECEIVED)) / EXPECTED. Example: FM_RDS_BLOCKCOUNT Command Action Data Description CMD 0x37 FM_RDS_BLOCKCOUNT ARG1 0x01 Clear the block count. STATUS 0x80 CTS = 1 RESP1 0x00 RESP2 0x27 RESP3 0x1F RESP4 0x24 RESP5 0x8B RESP6 0x00 RESP7 0x1B Expected 0x271F = 10015 Received 0x248B = 9355 Uncorrectable 0x001B = 27 In this example, the BLER = (27 + (10015-9355)) / 10015 = 6.8%. 4. Send the FM_RDS_STATUS in response to a configured RDS interrupt or at a set time interval. For example, an interrupt can be configured when the 25 group FIFO has any number of entries between 1 and 25. Alternatively, the command can be sent every 88 ms (time for one group to be received) to 2.2 seconds (time for 25 groups to be received). The FM_RDS_STATUS command must be called once for each entry. The FIFOUSED field can be used to monitor FIFO status. Refer to the RDS and RBDS specifications for further decoding information. Example: FM_RDS_STATUS Command Action Data Description CMD 0x36 FM_RDS_STATUS ARG1 0x01 Acknowledge the STC interrupt. STATUS 0x80 CTS = 1 RESP1 0x00 RESP2 0x1A TP/PTY has changed, PI has changed, synchronization has changed. RESP3 0x05 PTY = 5 RESP4 0x3E PI = 0x3E67 Rev. 0.9 277 AN543 FM_RDS_STATUS Command Action Data RESP5 0x67 RESP6 0x01 FIFO used = 1 (out of a maximum of 25) RESP7 0x00 BLEA = 0, BLEB = 0, BLEC = 0, BLED = 0 RESP8 0x3E BLOCKA = 0x3E67 (PI code) RESP9 0x67 RESP10 0x20 RESP11 0xA7 RESP12 0x6C RESP13 0x74 RESP14 0x65 RESP15 0x72 Description BLOCKB = 0x20A7, group 2A (RadioText), PTY = 5, A/B flag = 0, text segment address code = 7 BLOCKC = 0x6C74 (ASCII) = "lt" BLOCKD = 0x6572 (ASCII) = "er" 5. Repeat steps 3 and 4 as necessary. 278 Rev. 0.9 AN543 8.2.4. Check CTS and ERR Status After every command the CTS bit state should be checked to determine whether it is safe to send the next command and the ERR bit state should be checked to determine whether an error has occurred. Start 1. Start Timer 2. Read STATUS and RESP1 3. CTS = 1? No 4 .Timer > 125 ms? No 4. Wait tCTS Yes Yes 5. ERR = 0? 4. STOP No 6. ERR = 0x18? Yes Yes 6. Set CANCEL =1 and call FM_RSQ_STATUS or AM_RSQ_STATUS End 6. Wait 5ms No 7. ERR = 0x20, 0x30 or 0x31? No Yes 7. STOP 6. Set STCACK =1 and call FM_RSQ_STATUS or AM_RSQ_STATUS 6. Wait tCTS Rev. 0.9 279 AN543 1. Start a timer capable of measuring 100 s to 125 ms. 2. Read the STATUS byte and RESP1. 3. If CTS is set, it is safe to send the next command. Go to step 5. 4. If CTS is not set, check if the timer measures greater than 125 ms (time to execute the POWER_UP command plus 20% margin). If it does, it is likely that the receiver is not in the power up state. Refer to "5. Powerup and Powerdown" on page 3. If it doesn't, wait time tCTS (100 s). Refer to "6. Timing" on page 14. 5. If ERR (error) is set, check the specific error code reported in RESP1. 6. If the error code is 0x18, the tune or seek command is in progress and should be aborted by setting CANCEL = 1 and sending the FM_RSQ_STATUS command (or AM_RSQ_STATUS), waiting 5 ms for the seek operation to abort and set the STC bit, acknowledge and clear the STC bit by setting STCACK = 1 and sending the FM_RSQ_STATUS command (or AM_RSQ_STATUS) again, and then waiting time tCTS (100 s). Refer to "6. Timing" on page 14. 7. If the error code is 0x30 or 0x31 the boot operation failed and the powerup operation should be attempted. Refer to "5. Powerup and Powerdown" on page 3. If the error code is 0x20 contact Silicon Labs. All other errors are recoverable. and the error code reported in RESP1 will clear when the next valid command is sent. See Table 17. Table 17. Error Codes and Remedies RESP1 0x10 Bad command 0x11 Bad ARG1 0x12 Bad ARG2 0x13 Bad ARG3 0x14 Bad ARG4 0x18 Command Busy 0x20 280 Error Code Explanation and Remedy Unsupported command, possibly due to programming error or incorrect device population. For example an Si4751 is mistakenly placed on a design instead of the Si4755 and FM tune is attempted. Argument out of range or invalid mode, possibly due to programming error or incorrect device population. Wait for command completion, or abort tune/seek. Bad internal memory Internal memory corruption. Contact Silicon Labs. 0x30 Bad patch Patch CRC is incorrect. Recover by repeating the powerup sequence with correct patch. 0x31 Bad boot mode Mode is not supported (for example RDS on an Si4752). Recover by repeating the powerup sequence with supported mode (AM, FM). 0x40 Bad property Unsupported property, possibly due to programming error or incorrect device population. Rev. 0.9 AN543 8.2.5. Check STC Status After every command the STC (seek/tune complete) bit state should be checked to determine the state of the tune or seek command and abort the operation if desired. Start 1. Read STATUS 2. STC = 1? No 3. User Abort? Yes Yes 2. Set STCACK = 1, set ATTUNE = 1 and call FM_RSQ_STATUS or AM_RSQ_STATUS 3. Set CANCEL = 1 and call FM_RSQ_STATUS or AM_RSQ_STATUS 2. Wait tCTS 3. Wait 5ms No 4. Wait tSTC End 1. Read the STATUS byte. 2. If STC (seek/tune complete) is set, set STCACK = 1 to acknowledge and clear the STC bit and set ATTUNE = 1 to return RSQ metrics from tune time and call FM_RSQ_STATUS (or AM_RSQ_STATUS). Rev. 0.9 281 AN543 Example: FM_RSQ_STATUS Command Action Data Description CMD 0x32 FM_RSQ_STATUS ARG1 0x05 Return metrics from tune time, acknowledge the STC interrupt. STATUS 0x81 CTS = 1, STC = 1 RESP1 0x00 RESP2 0x31 SNR ready, RSSI ready, valid channel. RESP3 0x27 Tuning frequency 0x027A6 = 101.50 MHz RESP4 0xA6 RESP5 0x10 Frequency offset = 16 ppm RESP6 0x25 RSSI = 37 dBV RESP7 0x14 SNR = 20 dB RESP8 0x00 RESP9 0xFB -100 kHz channel signal strength (LASSI) 0xFB = -5 dB RESP10 0xF4 +100 kHz channel signal strength (HASSI) 0xFB = -12 dB RESP11 0x00 RESP12 0x0F Reserved, values will vary. RESP13 0x00 0x000 = Antenna capacitance, only for tracking filter applications RESP14 0x00 RESP15 0xE5 200 kHz channel signal strength (ASSI) 0xE5 = -27 dB RESP16 0x2A Ultrasonic noise (USN) 0x2A = 42 3. If STC is not set and the user wishes to abort the tune, set CANCEL = 1 to abort and call FM_RSQ_STATUS (or AM_RSQ_STATUS). Wait 5 ms for the tune or seek to abort and set the STC bit. 4. Wait tSTC (21-40 ms depending AM or FM modes). Refer to "6. Timing" on page 14. 282 Rev. 0.9 AN543 DOCUMENT CHANGE LIST Revision 0.1 to Revision 0.2 Revised "1. Introduction" on page 1. Added "4. Control Interface" on page 2. Added "5. Powerup and Powerdown" on page 3. Added "6. Timing" on page 14. Revised "7. Commands and Properties" on page 19. Added "8. Programming Examples" on page 266. Removed appendixes. Revision 0.2 to Revision 0.3 Added new softmute engines. Added new metrics to RSQ response. Added new metrics to Seek/Tune validation. Added new Channel Filter Bandwidth control engine. Added FM keyed AGC. Recommend new power-up sequence for 4 MHz crystal operation. Revision 0.3 to Revision 0.4 Added 6-Tap channel equalizer properties. Added "Property 0x40A-0x411" to FM section. Revision 0.4 to Revision 0.5 Added Si475x-40 information. Updated properties. Added Crystal XCLOAD calibration procedure. Revision 0.5 to Revision 0.6 Updated properties. Updated commands. Added Property 0x3210 FM_POP_NOISE_SCALE. Added blend CHBW properties 0x3518-0x351B. Added HICUTN CHBW properties 0x3618-0x361B. Added HIBLEND CHBW properties 0x3718-0x371B. Revision 0.6 to Revision 0.7 Updated " Property 0x3518 FM_BLEND_CHBW_LIMITS (Si4754/55/56/57 Only)" on page 171. " Property 0x3519 FM_BLEND_CHBW_STEREO_SEP (Si4754/55/56/57 Only)" on page 172. Updated " Property 0x3618 FM_HICUTN_CHBW_LIMITS (Si4754/55/56/57 Only)" on page 179. Updated " Property 0x3619 FM_HICUTN_CHBW_CUTOFF_FREQ (Si4754/55/56/57 Only)" on page 180. Updated " Property 0x3718 FM_HIBLEND_CHBW_LIMITS (Si4754/55/56/57 Only)" on page 187. Updated " Property 0x3719 FM_HIBLEND_CHBW_CUTOFF_FREQ (Si4754/55/56/57 Only)" on page 188. Rev. 0.9 283 AN543 Revision 0.7 to Revision 0.8 Updated the powerup sequence to a powerup sequence with an external circuit for the 4 MHz crystal detailed in "AN750: Si475x 4 MHz Crystal Circuit and Power-Up Procedure". Revision 0.8 to Revision 0.9 Added support for Si475xC parts. Added FM properties 0x2111 ~ 0x2118. Corrected description for property 0x360B. Changed "...based on RSSI" to "...based on Multipath". 284 Rev. 0.9 Smart. Connected. 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