20463-21 - CONEXANT SYSTEMS

Doc. No. 100490C

June 16, 2000

SmartSCM



 Modem

V.90/K56flex



/V.34/V.32bis CX88168 Single Chip Modem

with CX20463 SmartDAA



 and Optional CX20437 Voice

Codec for Embedded Applications

Data Sheet

Conexant Proprietary Information

SmartSCM Modem Data Sheet

ii Conexant 100490C

Revision Record

Revision Date Comments

C 6/16/2000 Revision B release. Supersedes 100490B.

B 6/2/2000 Revision B release. Supersedes 100490A and 100491A.

A 1/26/2000 Initial release.

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omissions in these materials. Conexant may make changes to specifications and product descriptions at any time, without notice. Conexant

makes no commitment to update the information and shall have no responsibility whatsoever for conflicts or incompatibilities arising from

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Technologies”™, ConfigurACE™, K56flex™, SmartDAA™, and SmartSCM™. Product names or services listed in this publication are for

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suggestions to tech.pubs@conexant.com. For technical questions, contact your local Conexant sales office or field applications engineer.

SmartSCM Modem Data Sheet

100490C Conexant iii

Contents

1 INTRODUCTION................................................................................................................................................. 1-1

1.1 Overview................................................................................................................................................... 1-1

1.2 Features ................................................................................................................................................... 1-4

1.2.1 General Modem Features .......................................................................................................... 1-4

1.2.2 SmartDAA Features ................................................................................................................... 1-5

1.2.3 Applications................................................................................................................................ 1-5

1.3 Technical Overview .................................................................................................................................. 1-5

1.3.1 General Description ................................................................................................................... 1-5

1.3.2 MCU Firmware ........................................................................................................................... 1-5

1.3.3 Operating Modes........................................................................................................................ 1-6

Data/Fax Modes................................................................................................................ 1-6

Synchronous Access Mode (SAM) - Video Conferencing................................................. 1-6

Worldwide Operation ........................................................................................................ 1-6

TAM Mode......................................................................................................................... 1-7

Voice/Speakerphone Mode (S Models)............................................................................. 1-7

1.3.4 Reference Design ...................................................................................................................... 1-7

1.3.5 GSM (Parallel Host Interface) .................................................................................................... 1-7

1.4 Hardware Description............................................................................................................................... 1-7

1.4.1 CX88168 Single Chip Modem.................................................................................................... 1-7

1.4.2 Digital Isolation Barrier............................................................................................................... 1-8

1.4.3 CX20463 SmartDAA Line Side Device ...................................................................................... 1-8

1.4.4 CX20437 Voice Codec............................................................................................................... 1-8

1.5 Commands ............................................................................................................................................... 1-8

2 TECHNICAL SPECIFICATIONS......................................................................................................................... 2-1

2.1 Serial DTE Interface Operation ................................................................................................................ 2-1

2.1.1 Automatic Speed/Format Sensing .............................................................................................2-1

2.2 Parallel Host Bus Interface Operation ...................................................................................................... 2-1

2.3 Establishing Data Modem Connections ................................................................................................... 2-1

Telephone Number Directory ............................................................................................ 2-1

Dialing ............................................................................................................................... 2-1

Modem Handshaking Protocol.......................................................................................... 2-2

Call Progress Tone Detection ........................................................................................... 2-2

Answer Tone Detection..................................................................................................... 2-2

Ring Detection................................................................................................................... 2-2

Billing Protection ............................................................................................................... 2-2

Connection Speeds........................................................................................................... 2-2

Automode.......................................................................................................................... 2-2

2.4 Data Mode................................................................................................................................................ 2-3

Speed Buffering (Normal Mode) ....................................................................................... 2-3

Flow Control ...................................................................................................................... 2-3

Escape Sequence Detection............................................................................................. 2-3

BREAK Detection.............................................................................................................. 2-3

Telephone Line Monitoring................................................................................................ 2-3

Send SPACE on Disconnect (V.22 bis and Below)........................................................... 2-3

Fall Forward/Fallback (V.90/K56flex/V.34/V.32 bis/V.32) ................................................. 2-3

Retrain............................................................................................................................... 2-3

Programmable Inactivity Timer ......................................................................................... 2-3

DTE Signal Monitoring (Serial DTE Interface Only) .......................................................... 2-4

2.5 Error Correction and Data Compression .................................................................................................. 2-4

V.42 Error Correction ........................................................................................................ 2-4

MNP 2-4 Error Correction.................................................................................................. 2-4

V.42 bis Data Compression .............................................................................................. 2-4

MNP 5 Data Compression ................................................................................................ 2-4

SmartSCM Modem Data Sheet

iv Conexant 100490C

2.6 MNP 10 Data Throughput Enhancement ................................................................................................. 2-4

2.7 MNP 10EC™ Enhanced Cellular Connection .......................................................................................... 2-4

2.8 Telephony Extensions .............................................................................................................................. 2-5

2.8.1 Line In Use Detection................................................................................................................. 2-5

2.8.2 Extension Pickup Detection ....................................................................................................... 2-5

2.8.3 Remote Hangup Detection......................................................................................................... 2-5

2.9 Fax Class 1, Fax Class 1.0, and Fax Class 2 Operation.......................................................................... 2-5

2.10 Voice/Audio Mode .................................................................................................................................... 2-5

2.10.1 Online Voice Command Mode ................................................................................................... 2-5

2.10.2 Voice Receive Mode .................................................................................................................. 2-5

2.10.3 Voice Transmit Mode ................................................................................................................. 2-6

2.10.4 Audio Mode................................................................................................................................ 2-6

2.10.5 Tone Detectors........................................................................................................................... 2-6

2.10.6 Speakerphone Modes................................................................................................................ 2-6

2.11 Full-Duplex Speakerphone (FDSP) Mode (S Models).............................................................................. 2-6

2.12 Caller ID ................................................................................................................................................... 2-6

2.13 Worldwide Country Support ..................................................................................................................... 2-7

2.14 Diagnostics............................................................................................................................................... 2-7

2.14.1 Commanded Tests..................................................................................................................... 2-7

2.14.2 Power On Reset Tests ............................................................................................................... 2-7

2.15 Low Power Sleep Mode............................................................................................................................ 2-7

2.16 GSM Operation......................................................................................................................................... 2-8

3 HARDWARE INTERFACE.................................................................................................................................. 3-1

3.1 CX88168 SCM Hardware Pins and Signals ............................................................................................. 3-1

3.1.1 Common to Parallel and Serial Interface Configurations ........................................................... 3-1

LSD Interface (Through DIB) ............................................................................................ 3-1

Call Progress Speaker Interface ....................................................................................... 3-1

Voice Relay Interface (S Models)...................................................................................... 3-1

Serial EEPROM Interface.................................................................................................. 3-1

External Bus Interface....................................................................................................... 3-1

Analog Cellular Phone Interface ....................................................................................... 3-1

3.1.2 Serial Interface Configuration Only ............................................................................................ 3-2

Serial DTE Interface and Indicator Outputs (PARIF = Low).............................................. 3-2

3.1.3 Parallel Interface Configuration Only (PARIF = High)................................................................ 3-2

Parallel Host Bus Interface................................................................................................ 3-2

GSM Interface ...................................................................................................................3-2

3.1.4 CX88168 SCM Interface Signals ............................................................................................... 3-2

3.2 CX20463 SmartDAA LSD Hardware Pins and Signals .......................................................................... 3-21

3.2.1 General .................................................................................................................................... 3-21

3.2.2 SCM Interface (Through DIB)................................................................................................... 3-21

3.2.3 Telephone Line Interface ......................................................................................................... 3-21

3.2.4 CX20463 LSD Pin Assignments and Signal Definitions........................................................... 3-21

3.3 CX20437 VC Hardware Pins and Signals (S Models)............................................................................ 3-26

3.3.1 General .................................................................................................................................... 3-26

Speakerphone Interface.................................................................................................. 3-26

Telephone Handset/Headset Interface (In Lieu of Analog Cellular Connection)............. 3-26

Analog Cellular Phone Interface (In Lieu of Telephone Handset/Headset

Connection).....................................................................................................................3-26

SCM Interface ................................................................................................................. 3-26

Host Interface..................................................................................................................3-26

3.3.2 CX20437 VC Pin Assignments and Signal Definitions............................................................. 3-26

3.4 Electrical and Environmental Specifications........................................................................................... 3-32

3.4.1 Operating Conditions, Absolute Maximum Ratings, and Power Requirements ....................... 3-32

3.4.2 Interface and Timing Waveforms .............................................................................................3-33

External Memory Bus Timing .......................................................................................... 3-33

Parallel Host Bus Timing................................................................................................. 3-35

Serial DTE Interface........................................................................................................ 3-37

4 PACKAGE DIMENSIONS................................................................................................................................... 4-1

SmartSCM Modem Data Sheet

100490C Conexant v

5 PARALLEL HOST INTERFACE......................................................................................................................... 5-1

5.1 Overview................................................................................................................................................... 5-1

5.2 Register Signal Definitions ....................................................................................................................... 5-3

5.2.1 IER - Interrupt Enable Register (Addr = 1, DLAB = 0) ............................................................... 5-3

5.2.2 FCR - FIFO Control Register (Addr = 2, Write Only) ................................................................. 5-4

5.2.3 IIR - Interrupt Identifier Register (Addr = 2)................................................................................ 5-5

5.2.4 LCR - Line Control Register (Addr = 3)...................................................................................... 5-6

5.2.5 MCR - Modem Control Register (Addr = 4)................................................................................ 5-7

5.2.6 LSR - Line Status Register (Addr = 5) ....................................................................................... 5-8

5.2.7 MSR - Modem Status Register (Addr = 6) ................................................................................. 5-9

5.2.8 RBR - RX Buffer (Receiver Buffer Register) (Addr = 0, DLAB = 0) ............................................ 5-9

5.2.9 THR - TX Buffer (Transmitter Holding Register) (Addr = 0, DLAB = 0)...................................... 5-9

5.2.10 Divisor Registers (Addr = 0 and 1, DLAB = 1) ........................................................................... 5-9

5.2.11 SCR - Scratch Register (Addr = 7)............................................................................................. 5-9

5.3 Receiver FIFO Interrupt Operation......................................................................................................... 5-10

5.3.1 Receiver Data Available Interrupt ............................................................................................ 5-10

5.3.2 Receiver Character Timeout Interrupts .................................................................................... 5-10

5.4 Transmitter FIFO Interrupt Operation..................................................................................................... 5-10

5.4.1 Transmitter Empty Interrupt ..................................................................................................... 5-10

SmartSCM Modem Data Sheet

vi Conexant 100490C

Figures

Figure 1-1. SmartSCM Modem Simplified Interface Diagram................................................................................................... 1-2

Figure 1-2. SmartSCM Modem Major Interfaces ...................................................................................................................... 1-3

Figure 3-1. CX88168 SCM Hardware Signals for Parallel Interface (PARIF = High) ............................................................... 3-3

Figure 3-2. CX88168 SCM 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High) .................................................. 3-4

Figure 3-3. CX88168 SCM Hardware Signals for Serial Interface (PARIF = Low) ................................................................. 3-11

Figure 3-4. CX88168 SCM 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low).................................................... 3-12

Figure 3-5. CX20463 LSD Hardware Interface Signals .......................................................................................................... 3-22

Figure 3-6. CX20463 LSD 32-Pin TQFP Pin Signals ............................................................................................................. 3-22

Figure 3-7. CX20437 VC Hardware Interface Signals ............................................................................................................ 3-27

Figure 3-8. CX20437 VC 32-Pin TQFP Pin Signals ............................................................................................................... 3-27

Figure 3-9. Waveforms - External Memory Bus ..................................................................................................................... 3-34

Figure 3-10. Waveforms - Parallel Host Bus .......................................................................................................................... 3-36

Figure 3-11. Waveforms - Serial DTE Interface ..................................................................................................................... 3-37

Figure 4-1. Package Dimensions - 128-Pin TQFP ................................................................................................................... 4-1

Figure 4-2. Package Dimensions - 32-pin TQFP...................................................................................................................... 4-2

Tables

Table 1-1. SmartSCM Modem Models and Functions.............................................................................................................. 1-2

Table 2-1. +MS Command Automode Connectivity ................................................................................................................. 2-2

Table 3-1. CX88168 SCM 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High) ................................................... 3-5

Table 3-2. CX88168 SCM Pin Signal Definitions for Parallel Interface (PARIF = High) ........................................................... 3-7

Table 3-3. CX88168 SCM 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low)..................................................... 3-13

Table 3-4. CX88168 SCM Pin Signal Definitions for Serial Interface (PARIF = Low)............................................................. 3-15

Table 3-5. CX88168 SCM I/O Type Definitions ...................................................................................................................... 3-20

Table 3-6. CX88168 SCM DC Electrical Characteristics ........................................................................................................ 3-20

Table 3-7. CX20463 LSD 32-Pin TQFP Pin Signals............................................................................................................... 3-23

Table 3-8. CX20463 LSD Pin Signal Definitions .................................................................................................................... 3-24

Table 3-9. CX20463 LSD DC Electrical Characteristics......................................................................................................... 3-25

Table 3-10. CX20437 VC 32-Pin TQFP Pin Signals............................................................................................................... 3-28

Table 3-11. CX20437 VC Pin Signal Definitions .................................................................................................................... 3-29

Table 3-12. CX20437 VC DC Electrical Characteristics......................................................................................................... 3-31

Table 3-13. CX20437 VC Analog Electrical Characteristics................................................................................................... 3-31

Table 3-14. Operating Conditions........................................................................................................................................... 3-32

Table 3-15. Absolute Maximum Ratings................................................................................................................................. 3-32

Table 3-16. Current and Power Requirements ....................................................................................................................... 3-32

Table 3-17. Timing - External Memory Bus ............................................................................................................................ 3-33

Table 3-18. Timing - Parallel Host Bus................................................................................................................................... 3-35

Table 5-1. Parallel Interface Registers ..................................................................................................................................... 5-2

Table 5-2. Interrupt Sources and Reset Control....................................................................................................................... 5-5

Table 5-3. Programmable Baud Rates ................................................................................................................................... 5-10

SmartSCM Modem Data Sheet

100490C Conexant 1-1

1 INTRODUCTION

1.1 Overview

The Conexant SmartSCM V.90/K56flex Modem Device Set with SmartDAA technology supports analog data up to 56

kbps, analog fax to 14.4 kbps, telephone answering machine (TAM)/telephony extensions, voice/speakerphone (optional),

GSM, analog cellular (optional), and parallel/serial host interface operation depending on model. Table 1-1 lists the available

models.

The modem operates with PSTN telephone lines worldwide and supports optional direct connect to an AMPS analog cellular

phone. The parallel host interface model also supports direct connect to a GSM phone.

Conexant's SmartDAA technology (patent pending) eliminates the need for a costly analog transformer, relays, and opto-

isolators typically used in discrete DAA (Data Access Arrangement) implementations The SmartDAA architecture also

simplifies product implementation by eliminating the need for country-specific board configurations enabling worldwide

homologation of a single modem board design and a single bill of materials (BOM).

The SmartDAA system-powered DAA operates reliably without drawing power from the line, unlike line-powered DAAs which

operate poorly when line current is insufficient due to long lines or poor line conditions. Enhanced features, such as

monitoring of local extension status without going off-hook, are also supported.

Incorporating Conexant’s proprietary Digital Isolation Barrier (DIB) design (patent pending) and other innovative DAA

features, the SmartDAA architecture simplifies application design, minimizes layout area, and reduces component cost.

The SmartSCM device set, consisting of a CX88168 Single Chip Modem (SCM) in a 128-pin TQFP and a CX20463

SmartDAA™ Line Side Device (LSD) in a 32-pin TQFP, supports data/fax/TAM operation with hardware-based modem

controller, digital signal processing, and DAA/telephone line interface functions (Figure 1-1 and Figure 1-2).

The SCM device integrates modem controller (MCU), modem data pump (MDP), 256k bytes ROM, 32k bytes RAM, and

SmartDAA system side device (SSD) functions onto a single die.

Modem functions for both parallel and serial interface configurations operate using only internal memory with the exception of

GSM which requires external memory. The external memory interface can also be used for customized modem code and

added/modified country profiles.

Low profile, small TQFP packages and low voltage operation with low power consumption make this device set ideal for

embedded and palmtop applications using parallel host or serial DTE interface.

The modem operates by executing firmware from internal ROM and RAM. Customized modem firmware can be executed

from optional external memory, either from ROM/flash ROM or from serial EEPROM and RAM. GSM operation requires an

external 1 Mbit (128k x 8) ROM/flash ROM.

In V.90/K56flex data mode (/56 models), the modem can receive data at line speeds up to 56 kbps from a digitally connected

V.90 or K56flex-compatible central site modem. In this mode, the modem can transmit data at line speeds up to V.34 rates.

In V.34 data mode (/56 and /33 models), the modem operates at line speeds up to 33.6 kbps. When applicable, error

correction (V.42/MNP 2-4) and data compression (V.42 bis/MNP 5) maximize data transfer integrity and boost average data

throughput. Non-error-correcting mode is also supported.

In V.32 bis data mode, the modem operates at lines speeds up to 14.4 kbps.

In V.22 bis fast connect mode, the modem can connect at 2400 bps with a very short training time, which is very efficient for

small data transfers.

Fax Group 3 send and receive rates are supported up to 14.4 kbps with T.30 protocol.

V.80 synchronous access mode supports host-controlled communication protocols, e. g., H.324 video conferencing.

In TAM mode, enhanced 2-bit or 4-bit per sample coding schemes at 8 kHz sample rate provide flexible format compatibility

and allows efficient digital storage of voice/audio. Also supported are 8-bit linear and IMA 4-bit ADPCM coding. This mode

supports applications such as digital telephone answering machine (TAM), voice annotation, and recording from and playback

to the telephone line.

S models, using the optional CX20437 Voice Codec (VC) in a 32-pin TQFP, support position independent, full-duplex

speakerphone (FDSP) operation using microphone and speaker, as well as other voice/TAM applications using handset or

headset. S models can also support analog cellular operation with direct connection to an analog cellular phone (in lieu of a

telephone handset/headset connection).

SmartSCM Modem Data Sheet

1-2 Conexant 100490C

GSM operation supports data services offered by the Global System for Mobile Communications network: data transmissions

to PSTN, ISDN or GSM users. GSM data operation allows data and fax transfer, and connection to videotex.

Analog cellular and GSM direct connect operation is supported by licensed firmware for specific phone types.

This data sheet describes the modem capabilities. Commands and parameters are defined in the Commands Reference

Manual (Doc. No. 100722).

Table 1-1. SmartSCM Modem Models and Functions

Model/Order/Part Numbers Supported Functions

Marketing Name Device Set

Order No.

Single Chip

Modem (SCM)

[128-Pin TQFP]

Part No.

Line Side

Device (LSD)

[32-Pin TQFP]

Part No.

Voice Codec

(VC)

[32-Pin TQFP]

Part No.

V.90 and

K56flex

Data

V.34 Data V.32 bis Data,

V.17 Fax,

TAM,

Worldwide

Voice/FDSP,

Analog

Cellular

EMBEDDED APPLICATIONS

SmartSCM/56 DS56-L145-061 CX88168-11 20463-11 — Y Y Y —

SmartSCM/56S DS56-L145-071 CX88168-11 20463-11 20437-11 Y Y Y Y

SmartSCM/33 DS28-L189-061 CX88168-12 20463-11 — — Y Y —

SmartSCM/33S DS28-L189-071 CX88168-12 20463-11 20437-11 — Y Y Y

SmartSCM/14 DS96-L853-041 CX88168-13 20463-11 — — — Y —

SmartSCM/14S DS96-L853-051 CX88168-13 20463-11 20437-11 — — Y Y

AFTERMARKET APPLICATIONS

SmartSCM/56 DS56-L144-121 CX88168-11 20463-11 — Y Y Y —

SmartSCM/56S DS56-L144-131 CX88168-11 20463-11 20437-11 Y Y Y Y

Notes:

1. Model options:

S Voice/full-duplex speakerphone (FDSP) and analog cellular

56 56 kbps max. rate per V.90

33 33.6 kbps max. rate per V.34

14 14.4 kbps max. rate per V.32 bis.

2. Supported functions (Y = Supported; – = Not supported).

TAM Telephone answering machine (Voice playback and record through telephone line)

FDSP Full-duplex speakerphone and voice playback and record through telephone line, handset, and mic/speaker

3. For ordering purposes, the CX prefix may not be included in the part number for some devices. Also, the CX prefix may not appear in the part number as branded on

some devices.

CX88168

Single Chip Modem

(SCM)

128-Pin TQFP

CX20463

SmartDAA

Line Side

Device (LSD)

32-Pin TQFP

CX20437

Voice Codec

(VC)

32-Pin TQFP

(Optional)

MIC

SPEAKER

TIP

RING

Telephone

Line

Interface

Discrete

Components

100491_F1-1_SID

Digital

Isolation

Barrier

(DIB)

TIP

RING HANDSET (OPTIONAL)

TELEPHONE LINE

(OPTIONAL)

PARALLEL

HOST BUS OR

SERIAL DTE

INTERFACE

ANALOG CELL PHONE

(OPTIONAL)

GSM PHONE

(OPTIONAL)

Figure 1-1. SmartSCM Modem Simplified Interface Diagram

SmartSCM Modem Data Sheet

100490C Conexant 1-3

CX88168

Single Chip Modem (SCM)

128-Pin TQFP

CX20437

Voice Codec (VC)

32-Pin TQFP

(Optional)

SmartDAA

Interface

Modem Data

Pump (MDP)

Digital Speaker

Circuit (Optional)

Paralle Host

or Serial DTE

Interface

MIC

SPEAKER

100491_F1-2_FID

SOUNDUCER

HS Hybrid

Components

(Optional)

RAM

(32K x 8)

ROM

(256k x 8)

Cellular

Interface

GSM Interface

(Parallel host

interface only)

Optional RAM

Up to 1M (128K x 8)

Optional Flash ROM

Up to 4M (512K x 8)

[1M (128K x 8) required for

GSM with Base Modem Code

in Internal Flash ROM]

[4M (512K x 8) required for

GSM with Base Modem Code

in External Flash ROM]

Microcontroller

Unit (MCU)

Serial EEPROM

2K (256 x 8) to

256K (32K x 8)

(Optional)

TIP

RING

Telephone

Line Interface

Discrete

Components

TIP

RING

Voice Relay,

HS Pickup

Detector

(Optional)

TELEPHONE

LINE

TELEPHONE

HANDSET

Digital

Isolation

Barrier (DIB)

Components

CX20463 SmartDAA

Line Side Device (LSD)

32-Pin TQFP

Line

Side

DIB

Interface

(LSDI)

Codec

Telephone

Line

Interface

DAA Hardware

Rectifier

and Filter

Components

(Mic/Speaker)

Interface

(Optional)

Figure 1-2. SmartSCM Modem Major Interfaces

SmartSCM Modem Data Sheet

1-4 Conexant 100490C

1.2 Features

1.2.1 General Modem Features

• Data modem

− ITU-T V.90/K56flex (/56 models)/V.34 (/56 and /33 models), V.32bis, V.32, V.22 bis, V.22, V.23, and V.21;

Bell 212A and Bell 103

− V.42 LAPM and MNP 2-4 error correction

− V.42 bis and MNP 5 data compression

− MNP 10EC™ enhanced cellular performance

− V.250 and V.251 commands

• V.22 bis fast connect

• Analog cellular direct connect using optional CX20437 Voice Codec (S models)

• GSM cellular direct connect (parallel interface only)

• Fax modem send and receive rates up to 14.4 kbps

− V.17, V.29, V.27 ter, and V.21 channel 2

− EIA/TIA 578 Class 1 and T.31 Class 1.0, and EIA/TIA 578 Class 2 commands

• V.80 synchronous access mode supports host-controlled communication protocols with H.324 interface support

• Interfaces to optional external ROM/flash ROM and/or to optional external serial EEPROM and RAM for customized modem

firmware

• Downloadable Architecture

− Downloadable MCU firmware from the host/DTE to optional external flash ROM

− Downloadable MDP code modules from the MCU transparent to the host

• Data/Fax/Voice call discrimination

• Hardware-based modem controller

• Hardware-based digital signal processor (DSP)

• Worldwide operation

− Complies to TBR21 and other country requirements

− Caller ID detection

− Call progress, blacklisting

− Internal ROM includes default values for 29 countries

• Caller ID and distinctive ring detect

• Telephony/TAM

− V.253 commands

− 2-bit and 4-bit Conexant ADPCM, 8-bit linear PCM, and 4-bit IMA coding

− 8 kHz sample rate

− Concurrent DTMF, ring, and Caller ID detection

• Full-duplex speakerphone (FDSP) mode using optional CX20437 Voice Codec (S models)

− Microphone and speaker interface

− Telephone handset or headset interface

− Acoustic and line echo cancellation

− Microphone gain and muting

− Speaker volume control and muting

• Built-in host/DTE interface with speeds up to 230.4 kbps

− Parallel 16550A UART-compatible interface

− Serial ITU-T V.24 (EIA/TIA-232-E) logical interface

• Direct mode (serial DTE interface)

• Flow control and speed buffering

• Automatic format/speed sensing

• Serial async data; parallel async data

• Thin packages support low profile designs (1.6 mm max. height)

− CX88168 SCM: 128-pin TQFP

− CX20463 LSD: 32-pin TQFP

− CX20437 VC: 32-pin TQFP

• +3.3V operation with +5V tolerant digital inputs

• Typical power use

SCM and LSD: 470 mW (Normal Mode); 140 mW (Sleep Mode)

VC: 5 mW (Normal Mode)

SmartSCM Modem Data Sheet

100490C Conexant 1-5

1.2.2 SmartDAA Features

• System side powered DAA operates under poor line current supply conditions

• Wake-on-ring

• Ring detection

• Line polarity reversal detection

• Line current loss detection

• Pulse dialing

• Line-in-use detection – detects even while on-hook

• Remote hang-up detect – for efficient call termination

• Extension pickup detect

• Call waiting detection

• Digital PBX line protection

• Meets worldwide DC VI Masks requirements

1.2.3 Applications

• Handheld computers

• Gaming devices

• Point of sales terminals

• Remote monitoring and data collection systems

1.3 Technical Overview

1.3.1 General Description

Modem operation, including dialing, call progress, telephone line interface, telephone handset interface, optional

voice/speakerphone interface, optional analog cellular phone interface, GSM interface, and host interface functions are

supported and controlled through the V.250, V.251, and V.253-compatible command set.

The modem hardware connects to the host via a parallel or serial interface as selected by the PARIF input. The OEM adds a

crystal circuit, DIB components, telephone line interface, telephone handset/telephony extension interface,

voice/speakerphone interface, cellular interface, GSM interface, optional external serial EEPROM, optional external

ROM/flash ROM, optional external RAM, and other supporting discrete components as supported by the modem model

(Table 1-1) and required by the application to complete the system.

Customized modem firmware can be supported by the use of external memory in various combinations, e.g., either external

ROM/flash ROM (up to 256k bytes), or external serial EEPROM (256 to 32k bytes) and external RAM (up to 128k bytes). To

support country profile addition or modification, external serial EEPROM (256 to 32k bytes) can be installed. Customized code

can include OEM-defined commands, i.e., identification codes (I3), identifier string (I4), manufacturer identification (+GMI),

model identification (+GMM), and revision identification (+GMR), as well as code modification.

Parallel interface operation is selected by PARIF input high. Telephone line, cellular (AMPS) phone, or GSM phone interface

operation is selected by the LINE/CELL and LINE/GSM inputs. Installation of cellular phone driver is also required for cellular

phone interface operation. Installation of GSM firmware is also required for GSM phone interface operation.

Serial interface operation is selected by PARIF input low. Telephone line or cellular (AMPS) phone interface operation is

selected by the LINE/CELL input. Installation of cellular phone driver is also required for cellular phone interface operation.

1.3.2 MCU Firmware

MCU firmware performs processing of general modem control, command sets, data modem, error correction and data

compression (ECC), fax class 1, fax class 1.0, fax class 2, voice/audio/TAM/speakerphone, worldwide, V.80, and serial

DTE/parallel host interface functions according to modem models (Table 1-1).

MCU firmware can be customized to include OEM-defined commands, i.e., identification codes (I3), identifier string (I4),

manufacturer identification (+GMI), model identification (+GMM), and revision identification (+GMR), as well as code

modification.

SmartSCM Modem Data Sheet

1-6 Conexant 100490C

1.3.3 Operating Modes

Data/Fax Modes

In V.90/K56flex data modem mode (/56 models), the modem can receive data from a digital source using a V.90- or K56flex-

compatible central site modem at line speeds up to 56 kbps. Asymmetrical data transmission supports sending data at line

speeds up to V.34 rates. This mode can fallback to full-duplex V.34 mode and to lower rates as dictated by line conditions.

In V.34 data modem mode (/56 and /33 models), the modem can operate in 2-wire, full-duplex, asynchronous modes at line

rates up to 33.6 kbps. Data modem modes perform complete handshake and data rate negotiations. Using V.34 modulation

to optimize modem configuration for line conditions, the modem can connect at the highest data rate that the channel can

support from 33600 bps down to 2400 bps with automatic fallback. Automode operation in V.34 is provided in accordance

with PN3320 and in V.32 bis in accordance with PN2330. All tone and pattern detection functions required by the applicable

ITU or Bell standards are supported.

In V.32 bis data modem mode, the modem can operate at line speeds up to 14.4 kbps.

In V.22 bis fast connect data mode, the modem can connect at 2400 bps with a very short training time, which is very efficient

for small data transfers.

In fax modem mode, the modem can operate in 2-wire, half-duplex, synchronous modes and can support Group 3 facsimile

send and receive speeds of 14400, 12000, 9600, 7200, 4800, and 2400 bps. Fax data transmission and reception performed

by the modem are controlled and monitored through the EIA/TIA-578 Fax Class 1, T.31 Fax Class 1.0, or Fax Class 2

command interface. Full HDLC formatting, zero insertion/deletion, and CRC generation/checking are provided.

Synchronous Access Mode (SAM) - Video Conferencing

V.80 Synchronous Access Mode between the modem and the host/DTE is provided for host-controlled communication

protocols, e.g., H.324 video conferencing applications.

Voice-call-first (VCF) before switching to a videophone call is also supported.

Worldwide Operation

The modem operates in TBR21-compliant and other countries. Country-dependent modem parameters for functions such as

dialing, carrier transmit level, calling tone, call progress tone detection, answer tone detection, blacklisting, caller ID, and relay

control are programmable (see Section 2.13).

SmartDAA technology allows a single PCB design and single BOM to be homologated worldwide. Advanced features such as

extension pickup detection, remote hang-up detection, line-in-use detection, and digital PBX detection are supported.

Country code IDs are defined by ITU-T T.35.

Internal ROM includes default profiles for 29 countries including TBR21-compliant profiles. These profiles can be overridden

by modified values stored in external serial EEPROM. If optional external ROM/flash ROM is used, a maximum of 31 country

profiles can be stored in external ROM/flash ROM. Additional country profiles can also be stored in external serial EEPROM

(request additional country profiles from a Conexant Sales Office). The default countries supported are:

Country Country Code Country Country Code Country Country Code

Australia 09 India 53 Portugal 8B

Austria 0A Ireland 57 Singapore 9C

Belgium 0F Italy 59 South Africa 9F

Brazil 16 Japan 00 Spain A0

China 26 Korea 61 Sweden A5

Denmark 31 Malaysia 6C Switzerland A6

Finland 3C Mexico 73 Taiwan FE

France 3D Netherlands 7B United Kingdom B4

Germany 42 Norway 82 United States B5

Greece 46 Poland 8A

SmartSCM Modem Data Sheet

100490C Conexant 1-7

TAM Mode

TAM Mode features include 8-bit linear coding at 8 kHz sample rate. Tone detection/generation, call discrimination, and

concurrent DTMF detection are also supported. ADPCM (4-bit IMA) coding is also supported to meet Microsoft WHQL logo

requirements.

TAM Mode is supported by three submodes:

1. Online Voice Command Mode supports connection to the telephone line or, for S models, a

microphone/speaker/handset/headset.

2. Voice Receive Mode supports recording voice or audio data input from the telephone line or, for S models, a

microphone/handset/headset.

3. Voice Transmit Mode supports playback of voice or audio data to the telephone line or, for S models, a

speaker/handset/headset.

Voice/Speakerphone Mode (S Models)

S models include additional telephone handset, external microphone, and external speaker interfaces which support voice

and full-duplex speakerphone (FDSP) operation.

Hands-free full-duplex telephone operation is supported in Speakerphone Mode under host control. Speakerphone Mode

features an advanced proprietary speakerphone algorithm which supports full-duplex voice conversation with acoustic, line,

and handset echo cancellation. Parameters are constantly adjusted to maintain stability with automatic fallback from full-

duplex to pseudo-duplex operation. The speakerphone algorithm allows position independent placement of microphone and

speaker. The host can separately control volume, muting, and AGC in microphone and speaker channels.

1.3.4 Reference Design

A data/fax/TAM/speakerphone reference design for an external modem (RD00-D970) is available to minimize application

design time, reduce development cost, and accelerate market entry.

A design package is available in electronic form. This package includes schematics, bill of materials (BOM), vendor part list

(VPL), board layout files in Gerber format, and complete documentation.

1.3.5 GSM (Parallel Host Interface)

Supported GSM features include:

• Data modem

− V.21, V.23, V.22, V.22 bis, V.32

− ISDN interoperability: 300 bps to 9600 bps

• Transparent asynchronous mode up to 9600 bps

• Non-transparent mode (RLP) up to 9600 bps

• Fax modem send and receive rate up to 9600 bps

• AT GSM commands (ETSI 07.07)

• GSM direct connect

• Firmware interface for OEM-provided phone driver

• Automatic GSM cable presence detection

• Built-in parallel host (16550A UART) interface

GSM operation requires an external 1 Mbit (128k x 8) ROM/flash ROM. If optional external ROM/flash ROM is used for the

base modem code, GSM operation requires 1 Mbit of an the external 4 Mbits (512k x 8) ROM/flash ROM.

1.4 Hardware Description

SmartDAA technology (patent pending) eliminates the need for a costly analog transformer, relays, and opto-isolators that

are typically used in discrete DAA implementations. The programmable SmartDAA architecture simplifies product

implementation in worldwide markets by eliminating the need for country-specific components.

1.4.1 CX88168 Single Chip Modem

The CX88168 Single Chip Modem (SCM), packaged in a 128-pin TQFP, includes a Microcontroller (MCU), a Modem Data

Pump (MDP), 256k bytes internal ROM, 32k bytes internal RAM, and SmartDAA interface functions.

The SCM connects to host via a parallel host (PARIF = high) or a logical V.24 (EIA/TIA-232-E) serial DTE interface (PARIF =

low).

SmartSCM Modem Data Sheet

1-8 Conexant 100490C

The SCM performs the command processing and host interface functions. The crystal frequency is 28.224 MHz.

The SCM optionally connects to external OEM-supplied ROM/flash ROM and RAM over a non-multiplexed 19-bit address bus

and 8-bit data bus. GSM operation requires external 1M (128k x 8) ROM/flash ROM.

The SCM optionally connects to an external OEM-supplied serial EEPROM over a dedicated 2-line serial interface. The

capacity of the EEPROM can be 256 bytes up to 32k bytes. The EEPROM can hold information such as firmware

configuration customization, country code parameters, and cellular drivers.

The SCM performs telephone line signal modulation/demodulation in a hardware digital signal processor (DSP) which

reduces computational load on the host processor.

The SmartDAA Interface communicates with, and supplies power and clock to, the LSD through the DIB.

1.4.2 Digital Isolation Barrier

The OEM-supplied Digital Isolation Barrier (DIB) electrically DC isolates the SCM from the LSD and telephone line. The SCM

is connected to a fixed digital ground and operates with standard CMOS logic levels. The LSD is connected to a floating

ground and can tolerate high voltage input (compatible with telephone line and typical surge requirements).

The DIB transformer couples power and clock from the SCM to the LSD.

The DIB data channel supports bidirectional half-duplex serial transfer of data, control, and status information between the

SCM and the LSD over two lines.

1.4.3 CX20463 SmartDAA Line Side Device

The CX20463 SmartDAA Line Side Device (LSD) includes a Line Side DIB Interface (LSDI), a coder/decoder (codec), and a

Telephone Line Interface (TLI).

The LSDI communicates with, and receives power and clock from, the SmartDAA interface in the SCM through the DIB.

LSD power is received from the MDP PWRCLKP and PWRCLKN pins via the DIB through a half-wave rectifying diode and

capacitive power filter circuit connected to the DIB transformer secondary winding.

The CLK input is also accepted from the DIB transformer secondary winding through a capacitor and a resistor in series.

Information is transferred between the LSD and the SCM through the DIB_P and DIB_N pins. These pins connect to the SCM

DIB_DATAP and DIB_DATAN pins, respectively, through the DIB.

The TLI integrates DAA and direct telephone line interface functions and connects directly to the line TIP and RING pins, as

well as to external line protection components.

Direct LSD connection to TIP and RING allows real-time measurement of telephone line parameters, such as the telephone

central office (CO) battery voltage, individual telephone line (copper wire) resistance, and allows dynamic regulation of the off-

hook TIP and RING voltage and total current drawn from the central office (CO). This allows the modem to maintain

compliance with U.S. and worldwide regulations and to actively control the DAA power dissipation.

1.4.4 CX20437 Voice Codec

The optional CX20437 Voice Codec (VC), packaged in a 32-pin TQFP, supports voice/full-duplex speakerphone (FDSP)

operation with interfaces to a microphone and speaker and to a telephone handset/headset. The VC also supports and

analog cellular operation with direct connect interface to a cellular phone (in lieu of telephone handset/headset connection).

1.5 Commands

The modem supports data modem, fax class 1 modem, fax class 1.0 modem, fax class 2 modem, voice/audio, full-duplex

speakerphone (FDSP), MNP 10/MNP 10EC, and V.80 commands, and S Registers in accordance with modem model

options. See Doc. No. 100722 for a description of the commands.

Data Modem Operation. Data modem functions operate in response to the AT commands when +FCLASS=0. Default

parameters support U.S./Canada operation.

MNP 10 Operation. MNP 10 functions operate in response to MNP 10 commands.

MNP 10EC Operation. MNP 10EC is enabled by the -SEC=1 command.

Fax Modem Operation. Facsimile functions operate in response to fax class 1 commands when +FCLASS=1, fax class 1.0

commands when +FCLASS=1.0, or to fax class 2 commands when +FCLASS=2 is installed.

SmartSCM Modem Data Sheet

100490C Conexant 1-9

Voice/Audio Operation. Voice/audio mode functions operate in response to voice/audio commands when +FCLASS=8.

Speakerphone Operation. FDSP functions operate in response to speakerphone commands when +FCLASS=8 and

+VSP=1 is selected.

SmartSCM Modem Data Sheet

1-10 Conexant 100490C

This page is intentionally blank.

SmartSCM Modem Data Sheet

100490C Conexant 2-1

2 TECHNICAL SPECIFICATIONS

2.1 Serial DTE Interface Operation

2.1.1 Automatic Speed/Format Sensing

Command Mode and Data Modem Mode. The modem can automatically determine the speed and format of the data sent

from the DTE. The modem can sense speeds of 300, 600, 1200, 2400, 4800, 7200, 9600, 12000, 14400, 16800, 19200,

21600, 24000, 26400, 28800, 38400, 57600, 115200, and 230400 bps and the following data formats:

Parity

Data Length

(No. of Bits)

No. of

Stop Bits

Character Length

(No. of Bits)

None 7 2 10

Odd 7 1 10

Even 7 1 10

None 8 1 10

Odd 8 1 11*

Even 8 1 11*

*11-bit characters are sensed, but the parity bits are stripped off

during data transmission in Normal and Error Correction modes.

The modem can speed sense data with mark or space parity and configures itself as follows:

DTE Configuration Modem Configuration

7 mark 7 none

7 space 8 none

8 mark 8 none

8 space 8 even

Fax Modem Mode. In V.17 fax mode, the modem can sense speeds up to 230.4 kbps.

2.2 Parallel Host Bus Interface Operation

Command Mode and Data Modem Mode. The modem can operate at rates up to 230.4 kbps by programming the Divisor

Latch in the parallel interface registers if supported by communications software and/or driver (a Windows 95/98 driver is

available from Conexant).

Fax Modem Mode. In V.17 mode, the modem can operate at rates up to 230.4 kbps by programming the Divisor Latch in the

parallel interface registers if supported by communications software and/or driver (a Windows 95/98 driver is available from

Conexant).

2.3 Establishing Data Modem Connections

Telephone Number Directory

The modem supports four telephone number entries in a directory that can be saved in a serial NVRAM. Each telephone

number can be up to 32 characters (including the command line terminating carriage return) in length. A telephone number

can be saved using the &Zn=x command, and a saved telephone number can be dialed using the DS=n command.

Dialing

DTMF Dialing. DTMF dialing using DTMF tone pairs is supported in accordance with ITU-T Q.23. The transmit tone level

complies with Bell Publication 47001.

Pulse Dialing. Pulse dialing is supported in accordance with EIA/TIA-496-A.

Blind Dialing. The modem can blind dial in the absence of a dial tone if enabled by the X0, X1, or X3 command.

SmartSCM Modem Data Sheet

2-2 Conexant 100490C

Modem Handshaking Protocol

If a tone is not detected within the time specified in the S7 register after the last digit is dialed, the modem aborts the call

attempt.

Call Progress Tone Detection

Ringback, equipment busy, congested tone, warble tone, and progress tones can be detected in accordance with the

applicable standard.

Answer Tone Detection

Answer tone can be detected over the frequency range of 2100 ± 40 Hz in ITU-T modes and 2225 ± 40 Hz in Bell modes.

Ring Detection

A ring signal can be detected from a TTL-compatible 15.3 Hz to 68 Hz square wave input.

Billing Protection

When the modem goes off-hook to answer an incoming call, both transmission and reception of data are prevented for 2

seconds (data modem) or 4 seconds (fax adaptive answer) to allow transmission of the billing tone signal.

Connection Speeds

The modem functions as a data modem when the +FCLASS=0 command is active.

Line connection can be selected using the +MS command. The +MS command selects modulation, enables/disables

automode, and selects minimum and maximum line speeds (Table 2-1).

Automode

Automode detection can be enabled by the +MS command to allow the modem to connect to a remote modem in accordance

with draft PN-3320 for V.34 (Table 2-1).

Table 2-1. +MS Command Automode Connectivity

<mod> Modulation Possible Rates (bps) 1Notes

V21 V.21 300

V22 V.22 1200

V22B V.22 bis 2400 or 1200

V23 V.23 1200 See Note 2

V32 V.32 9600 or 4800

V32B V.32 bis 14400, 12000, 9600, 7200, or 4800 Default for /14

models

V34 V.34 33600, 31200, 28800, 26400, 24000, 21600, 19200, 16800,

14400, 12000, 9600, 7200, 4800, or 2400

Default for /33

models

V90 V.90 56000, 54667, 53333, 52000, 50667, 49333, 48000, 46667,

45333, 42667, 41333, 40000, 38667, 37333, 36000, 34667,

33333, 32000, 30667, 29333, 28000

Default for /56

models

K56 K56flex 56000, 54000, 52000, 50000, 48000, 46000, 44000, 42000,

40000, 38000, 36000, 34000, 32000

B103 Bell 103 300

B212 Bell 212 1200

Notes:

1. See optional <automode>, <min_rate>, and <max_rate> subparameters for the +MS command.

2. For V.23, originating modes transmit at 75 bps and receive at 1200 bps; answering modes transmit at 1200 bps and receive at

75 bps. The rate is always specified as 1200 bps. V.23 half duplex is not supported.

3. If the DTE speed is set to less than the maximum supported DCE speed in automode, the maximum connection speed is

limited to the DTE speed.

SmartSCM Modem Data Sheet

100490C Conexant 2-3

2.4 Data Mode

Data mode exists when a telephone line connection has been established between modems and all handshaking has been

completed.

Speed Buffering (Normal Mode)

Speed buffering allows a DTE to send data to, and receive data from, a modem at a speed different than the line speed. The

modem supports speed buffering at all line speeds.

Flow Control

DTE-to-Modem Flow Control. If the modem-to-line speed is less than the DTE-to-modem speed, the modem supports

XOFF/XON or RTS/CTS flow control with the DTE to ensure data integrity.

Escape Sequence Detection

The +++ escape sequence can be used to return control to the command mode from the data mode. Escape sequence

detection is disabled by an S2 Register value greater than 127.

BREAK Detection

The modem can detect a BREAK signal from either the DTE or the remote modem. The \Kn command determines the

modem response to a received BREAK signal.

Telephone Line Monitoring

GSTN Cleardown (V.90, K56flex, V.34, V.32 bis, V.32). Upon receiving GSTN Cleardown from the remote modem in a non-

error correcting mode, the modem cleanly terminates the call.

Loss of Carrier (V.22 bis and Below). If carrier is lost for a time greater than specified by the S10 register, the modem

disconnects (except MNP 10).

Receive Space Disconnect (V.22 bis and Below). If selected by the Y1 command in non-error-correction mode, the modem

disconnects after receiving 1.6 ± 10% seconds of continuous SPACE.

Send SPACE on Disconnect (V.22 bis and Below)

If selected by the Y1 command in non-error-correction mode, the modem sends 4 ± 10% seconds of continuous SPACE

when a locally commanded hang-up is issued by the &Dn or H command.

Fall Forward/Fallback (V.90/K56flex/V.34/V.32 bis/V.32)

During initial handshake, the modem will fallback to the optimal line connection within V.90/K56flex/V.34/V.32 bis/V.32 mode

depending upon signal quality if automode is enabled by the +MS or N1 command.

When connected in V.90/K56flex/V.34/V.32 bis/V.32 mode, the modem will fall forward or fallback to the optimal line speed

within the current modulation depending upon signal quality if fall forward/fallback is enabled by the %E2 command.

Retrain

The modem may lose synchronization with the received line signal under poor or changing line conditions. If this occurs,

retraining may be initiated to attempt recovery depending on the type of connection.

The modem initiates a retrain if line quality becomes unacceptable if enabled by the %E command. The modem continues to

retrain until an acceptable connection is achieved, or until 30 seconds elapse resulting in line disconnect.

Programmable Inactivity Timer

The modem disconnects from the line if data is not sent or received for a specified length of time. In normal or error-correction

mode, this inactivity timer is reset when data is received from either the DTE or from the line. This timer can be set to a value

between 0 and 255 seconds by using register S30. A value of 0 disables the inactivity timer.

SmartSCM Modem Data Sheet

2-4 Conexant 100490C

DTE Signal Monitoring (Serial DTE Interface Only)

DTR#. When DTR# is asserted, the modem responds in accordance with the &Dn and &Qn commands.

RTS#. RTS# is used for flow control if enabled by the &K command in normal or error-correction mode.

2.5 Error Correction and Data Compression

V.42 Error Correction

V.42 supports two methods of error correction: LAPM and, as a fallback, MNP 4. The modem provides a detection and

negotiation technique for determining and establishing the best method of error correction between two modems.

MNP 2-4 Error Correction

MNP 2-4 is a data link protocol that uses error correction algorithms to ensure data integrity. Supporting stream mode, the

modem sends data frames in varying lengths depending on the amount of time between characters coming from the DTE.

V.42 bis Data Compression

V.42 bis data compression mode, enabled by the %Cn command or S46 register, operates when a LAPM or MNP 10

connection is established.

The V.42 bis data compression employs a “string learning” algorithm in which a string of characters from the DTE is encoded

as a fixed length codeword. Two 2k-byte dictionaries are used to store the strings. These dictionaries are dynamically

updated during normal operation.

MNP 5 Data Compression

MNP 5 data compression mode, enabled by the %Cn command, operates during an MNP connection.

In MNP 5, the modem increases its throughput by compressing data into tokens before transmitting it to the remote modem,

and by decompressing encoded received data before sending it to the DTE.

2.6 MNP 10 Data Throughput Enhancement

MNP 10 protocol and MNP Extended Services enhance performance under adverse channel conditions such as those found

in rural, long distance, or cellular environments. An MNP 10 connection is established when an MNP 2-4 connection is

negotiated with a remote modem supporting MNP 10.

MNP Extended Services. The modem can quickly switch to MNP 10 operation when the remote modem supports MNP 10

and both modems are configured to operate in V.42.

V.42 bis/MNP 5 Support. V.42 bis/MNP 10 can operate with V.42 bis or MNP 5 data compression.

2.7 MNP 10EC™ Enhanced Cellular Connection

A traditional landline modem, when used for high-speed cellular data transmission, typically encounters frequent signal

interference and degradation in the connection due to the characteristics of the analog cellular network. In this case, cellular-

specific network impairments, such as non-linear distortion, fading, hand-offs, and high signal-to-noise ratio, contribute to an

unreliable connection and lower data transfer performance. Implementations relying solely on protocol layer methods, such as

MNP 10, generally cannot compensate for the landline modem's degraded cellular channel performance.

The modem achieves higher cellular performance by implementing enhanced cellular connection techniques at both the

physical and protocol layers, depending on modem model. The modem enhances the physical layer within the modulation by

optimizing its responses to sudden changes in the cellular connection. The MNP 10EC protocol layer implemented in the

modem firmware improves data error identification/correction and maximizes data throughput by dynamically adjusting speed

and packet size based on signal quality and data error performance.

SmartSCM Modem Data Sheet

100490C Conexant 2-5

2.8 Telephony Extensions

The following telephony extension features are supported and can be typically be implemented in designs for set-top box

applications and TAM software applications to enhance end-user experience:

• Line In Use detection

• Extension Pickup detection

• Remote Hang-up detection

2.8.1 Line In Use Detection

The Line In Use Detection feature can stop the modem from disturbing the phone line when the line is already being used.

When an automated system tries to dial using ATDT and the phone line is in use, the modem will not go off hook and will

respond with the message “LINE IN USE”.

2.8.2 Extension Pickup Detection

The Extension Pickup Detection feature (also commonly referred as PPD or Parallel phone detection) allows the modem to

detect when another telephony device (i.e., fax machine, phone, satellite/cable box) is attempting to use the phone line.

This feature can be used to quickly drop a modem connection in the event when a user picks up a extension phone line. For

example, this feature allows set top boxes with an integrated SmartSCM modem to give normal voice users the highest

priority over the telephone line.

This feature can also be used in Telephone Answering Machine applications (TAM). Its main use would be to stop the TAM

operation when a phone is picked up.

2.8.3 Remote Hangup Detection

The Remote Hangup Detection feature will cause the modem go back onhook during a data connection when the remote

modem is disconnected for abnormal termination reasons (remote phone line unplugged, remote server/modem shutdown.

For Voice applications, this method can be used in addition to silence detection to determine when a remote caller has hung

up to terminate a voice recording.

2.9 Fax Class 1, Fax Class 1.0, and Fax Class 2 Operation

Facsimile functions operate in response to fax class 1 commands when +FCLASS=1, fax class 1.0 commands when

+FCLASS=1.0, or to fax class 2 commands when +FCLASS=2 is installed

In the fax mode, the on-line behavior of the modem is different from the data (non-fax) mode. After dialing, modem operation

is controlled by fax commands. Some AT commands are still valid but may operate differently than in data modem mode.

Calling tone is generated in accordance with T.30.

2.10 Voice/Audio Mode

Voice and audio functions are supported by the Voice Mode. Voice Mode includes three submodes: Online Voice Command

Mode, Voice Receive Mode, and Voice Transmit Mode.

2.10.1 Online Voice Command Mode

This mode results from the connection to the telephone line or a voice/audio I/O device (e.g., microphone, speaker, or

handset) through the use of the +FCLASS=8 and +VLS commands. After mode entry, AT commands can be entered without

aborting the connection.

2.10.2 Voice Receive Mode

This mode is entered when the +VRX command is active in order to record voice or audio data input at the RIN pin, typically

from a microphone/handset or the telephone line.

Received analog voice samples are converted to digital form and compressed for reading by the host. AT commands control

the codec bits-per-sample rate.

Received analog mono audio samples are converted to digital form and formatted into 8-bit unsigned linear PCM format for

reading by the host. AT commands control the bit length and sampling rate. Concurrent DTMF/tone detection is available at

the 8 kHz sample rate.

SmartSCM Modem Data Sheet

2-6 Conexant 100490C

2.10.3 Voice Transmit Mode

This mode is entered when the +VTX command is active in order to playback voice or audio data to the TXA output, typically

to a speaker/handset or to the telephone line.

Digitized voice data is decompressed and converted to analog form at the original compression quantization sample-per-bits

rate then output to the TXA output.

Digitized audio data is converted to analog form then output to the TXA output.

2.10.4 Audio Mode

The audio mode enables the host to transmit and receive 8-bit audio signals. In this mode, the modem directly accesses the

internal analog-to-digital (A/D) converter (ADC) and the digital-to-analog (D/A) converter (DAC). Incoming analog audio

signals can then be converted to digital format and digital signals can be converted to analog audio output.

2.10.5 Tone Detectors

The tone detector signal path is separate from the main received signal path thus enabling tone detection to be independent

of the configuration status. In Tone Mode, all three tone detectors are operational.

2.10.6 Speakerphone Modes

Speakerphone modes are controlled in voice mode with the following commands:

Use Speakerphone After Dialing or Answering (+VSP=1). +VSP=1 selects speakerphone mode while in +FCLASS=8

mode. Speakerphone operation is entered during Voice Online Command mode after completing dialing or answering.

Speakerphone Settings. The +VGM and +VGS commands can be used to control the microphone gain and speaker volume,

respectively. The VGM and +VGS commands are valid only after the modem has entered the Voice Online mode while in the

+VSP=1 setting.

2.11 Full-Duplex Speakerphone (FDSP) Mode (S Models)

The modem operates in FDSP mode when +FCLASS=8 and +VSP=1 (see Section 2.10.6).

In FDSP Mode, speech from a microphone or handset is converted to digital form, shaped, and output to the telephone line

through the line interface circuit. Speech received from the telephone line is shaped, converted to analog form, and output to

the speaker or handset. Shaping includes both acoustic and line echo cancellation.

2.12 Caller ID

Caller ID can be enabled/disabled using the +VCID command. When enabled, caller ID information (date, time, caller code,

and name) can be passed to the DTE in formatted or unformatted form. Inquiry support allows the current caller ID mode and

mode capabilities of the modem to be retrieved from the modem.

SmartSCM Modem Data Sheet

100490C Conexant 2-7

2.13 Worldwide Country Support

Internal modem firmware supports 29 country profiles (see Section 1.3.2). These country profiles include the following

country-dependent parameters:

• Dial tone detection levels and frequency ranges.

• DTMF dialing parameters: Transmit output level, DTMF signal duration, and DTMF interdigit interval.

• Pulse dialing parameters: Make/break times, set/clear times, and dial codes are programmable

• Ring detection frequency range.

• Blind dialing enabled/disable.

• Carrier transmit level (through S91 for data and S92 for fax). The maximum, minimum, and default values can be defined

to match specific country and DAA requirements.

• Calling tone is generated in accordance with V.25. Calling tone may be toggled (enabled/disabled) by inclusion of a “^”

character in a dial string. It may also be disabled.

• Frequency and cadence of tones for busy, ringback, congested, warble, dial tone 1, and dial tone 2.

• Answer tone detection period.

• Blacklist parameters. The modem can operate in accordance with requirements of individual countries to prevent misuse

of the network by limiting repeated calls to the same number when previous call attempts have failed. Call failure can be

detected for reasons such as no dial tone, number busy, no answer, no ringback detected, voice (rather than modem)

detected, and key abort (dial attempt aborted by user). Actions resulting from such failures can include specification of

minimum inter-call delay, extended delay between calls, and maximum numbers of retries before the number is

permanently forbidden ("blacklisted").

These country profiles may be altered or customized by modifying the country-dependent parameters. Additional profiles may

also be included. There are two ways to add or modify profiles:

• Linking additional or modified profiles from an external serial EEPROM.

• Incorporating additional or modified profiles into optional external flash ROM containing the entire modem firmware code.

Please contact an FAE at the local Conexant sales office if a country code customization is required.

2.14 Diagnostics

2.14.1 Commanded Tests

Diagnostics are performed in response to &T commands.

Analog Loopback (&T1 Command). Data from the local DTE is sent to the modem, which loops the data back to the local

DTE.

2.14.2 Power On Reset Tests

Upon power on, the modem performs tests of the modem, internal and external RAM, and NVRAM. If the modem, internal

RAM, or external RAM test fails, the TMIND# output is pulsed (serial interface version) or the DCD bit in the parallel interface

Internal or external RAM test fails: One pulse cycle (pulse cycle = 0.5 sec. on, 0.5 sec. off) every 1.5 seconds.

Modem device test fails: Three pulse cycles every 1.5 seconds.

If the NVRAM test fails (due to NVRAM failure or if NVRAM is not installed), the test failure is reported by AT commands that

normally use the NVRAM, e.g., the &V command.

2.15 Low Power Sleep Mode

Sleep Mode Entry. The modem enters the low power sleep mode when no line connection exists and no host activity occurs

for the period of time specified in the S24 register. All modem circuits are turned off except the internal clock circuitry in order

to consume reduced power while being able to immediately wake up and resume normal operation.

Wake-up. Wake-up occurs when a ring is detected on the telephone line, the host writes to the modem (parallel interface), or

the DTE sends a character to the modem (serial interface).

SmartSCM Modem Data Sheet

2-8 Conexant 100490C

2.16 GSM Operation

Once the modem is connected to the GSM phone and the phone is powered on, dial/answer functions will be routed through

the phone instead of the wireline DAA. No special commands are needed to place or answer GSM calls and the same AT

commands and software packages that are used for wireline communication sessions can be used.

While the modem is being used with a GSM phone, result messages are changed from wireline operation status to reflect

GSM operation status as follows:

NO DIALTONE - Indicates that GSM service is not currently available or the cellular phone is powered off.

RING - Indicates that the GSM phone is receiving an incoming call.

BUSY - The network reports the number dialed is busy.

CARRIER - The carrier is established with the IWF (Interworking function) modem.

PROTOCOL RLP - The error corrected protocol on the radio link is established.

SmartSCM Modem Data Sheet

100490C Conexant 3-1

3 HARDWARE INTERFACE

3.1 CX88168 SCM Hardware Pins and Signals

3.1.1 Common to Parallel and Serial Interface Configurations

LSD Interface (Through DIB)

The DIB interface signals are:

• Clock and Power Positive (PWRCLKP); output

• Clock and Power Negative (PWRCLKN); output

• Data Positive (DIB_DATAP); input/output

• Data Negative (DIB_DATAN); input/output

Call Progress Speaker Interface

The call progress speaker interface signal is:

• Digital speaker output (DSPKOUT); output

DSPKOUT is a square wave output in Data/Fax mode used for call progress or carrier monitoring. This output can be

optionally connected to a low-cost on-board speaker, e.g., a sounducer, or to an analog speaker circuit.

Voice Relay Interface (S Models)

The voice relay interface signal is:

• Voice Relay Control (VOICE#); output

Serial EEPROM Interface

A 2-line serial interface to an optional serial EEPROM is supported. The interface signals are:

• Bidirectional Data input/output (NVMDATA)

• Clock output (NVMCLK)

The EEPROM can hold information such as firmware customization, country code parameters, and cellular drivers. Data

stored in EEPROM takes precedence over the factory default settings.

The EEPROM size can range from 2 kbits (256 x 8) to 256 kbits (32k x 8). A 2k EEPROM must be 100 kHz or 400 kHz; higher

capacity EEPROMs must be 400 kHz.

External Bus Interface

The external bus can connect to optional OEM-supplied external memory:

• Up to 4 Mbits (512k x 8) ROM/flash ROM (1 Mbit is required for optional GSM)

• Up to 1 Mbit (128k x 8) RAM

The non-multiplexed external bus interface signals are:

• Eight bidirectional Data lines (D0-D7)

• 19 Address output lines (A0-A18)

• Read Enable output (READ#)

• Write Enable output (WRITE#)

• ROM Chip Select output (ROMSEL#)

• RAM Chip Select output (RAMSEL#)

Analog Cellular Phone Interface

Analog cellular operation is selected when the LINE/CELL input is low and a cellular firmware driver is loaded. Signals

supported are:

• Cell RX Bias output (RXPAD#)

• Cell TX Bias output (TXPAD#)

• Cell bidirectional Serial Data line (CELDATA)

• Cell data Clock input (CELCLK)

• Cell Busy output (CELBSY)

• Cell Busy input (CELBSY#)

SmartSCM Modem Data Sheet

3-2 Conexant 100490C

NOTE: The following analog cellular interface signals are supported by the CX20437 VC:

• Cell receive analog input (CEL_RX)

• Cell transmit analog output (CEL_TX)

3.1.2 Serial Interface Configuration Only

Serial DTE Interface and Indicator Outputs (PARIF = Low)

A V.24/EIA/TIA-232-E logic-compatible serial DTE interface is selected when the PARIF input is low.

The supported DTE interface signals are:

• Serial Transmit Data input (TXD#)

• Serial Receive Data output line (RXD#)

• Clear to Send output (CTS#)

• Data Set Ready output (DSR#)

• Received Line Signal Detector (RLSD#)

• Test Mode output (TM#)

• Ring Indicator (RI#)

• Data Terminal Ready control input (DTR#)

• Request to Send control input (RTS#)

The following indicator output lines are also supported:

• Auto Answer indicator output (AAIND#)

• Data Terminal Ready indicator output (DTRIND#)

• Test Mode indicator output (TMIND#)

• Off-hook indicator output (OHIND#) (supported in non-cellular mode)

3.1.3 Parallel Interface Configuration Only (PARIF = High)

A 16550A UART-compatible parallel host bus interface is selected when the PARIF input is high.

Parallel Host Bus Interface

The parallel host interface signals are:

• Host Reset control input line (RESET#)

• Host Chip Select control input (HCS#)

• Host Read control input (HRD#)

• Host Write control input (HWT#)

• Host Interrupt output line (HINT)

• Three Host Address input lines (HA0-HA2)

• Eight Host Data lines (HD0-HD7)

GSM Interface

GSM operation is selected when the LINE/GSM input is low and GSM firmware is loaded in external ROM/flash ROM. Signals

supported are:

• GSM TX Bias output (TXPAD#)

• GSM RX Bias output (RXPAD#)

• GSM Control input (GSMINP0)

• GSM serial Transmit Data output (GSMTXD)

• GSM serial Receive Data input (GSMRXD)

3.1.4 CX88168 SCM Interface Signals

SCM 128-pin TQFP hardware interface signals for parallel interface are shown by major interface in Figure 3-1, are shown by

pin number in Figure 3-2, and are listed by pin number in Table 3-1. The SCM hardware interface signals for parallel interface

are defined in Table 3-2.

SCM 128-pin TQFP hardware interface signals for serial interface are shown by major interface in Figure 3-3, are shown by

pin number in Figure 3-4, and are listed by pin number in Table 3-3. The SCM hardware interface signals for serial interface

are defined in Table 3-4.

SCM I/O types are defined in Table 3-5.

SCM DC electrical characteristics are listed in Table 3-6.

SmartSCM Modem Data Sheet

100490C Conexant 3-3

XTLI

XTLO

CLKIN

CLKOUT

XCLK

RESERVED (P_PA01)

NOXYCK

PARIF

STPMODE# (PD3)

NMI#

RESET#

HCS# (PD4)

HRD# (PD6)

HWT# (PD5)

HINT (PB7)

HA0 (PD0)

HA1 (PD1)

HA2 (PD2)

HD0 (PC0)

HD1 (PC1)

HD2 (PC2)

HD3 (PC3)

HD4 (PC4)

HD5 (PC5)

HD6 (PC6)

HD7 (PC7)

SSD_RINGWAKE (PA0)

SSD_RING# (PE6)

SSD_INT (PA1)

TESTP

DV1TP

PHS2

SR4IN

PD7

RESERVED (PB1)

RESERVED (P_PA00)

RESERVED (P_PA04)

RESERVED (P_PA05)

RESERVED (P_PB01)

RESERVED (BD2CLK)

RESERVED (P_GP00)

P_PX00

P_PX02

P_PX03

VGG

VDD

GND

114

115

113

117

109

122

123

125

126

127

110

111

121

101

100

108

116

124

103

112

120

128

HOST

PARALLEL

BUS

LINE/CELL (PE7)

LINE/GSM (PA5)

GSMRXD (PA2)

GSMTXD (PA6)

CELCLK/GSMINP0 (PA4)

CELDATA (PE5)

CELBSY (PE2)

CELBSY# (PA3)

RXPAD# (PE0)

VOICE#/TXPAD# (PE1)

HS_LCS (PE4)

DSPKOUT

PWRCLKP

PWRCLKN

DIB_DATAP

DIB_DATAN

IASLEEP (P_PF05)

M_CLK (P_PB00)

SR2CLK (P_PGP05)

SA2CLK (P_PX05)

SR3OUT

SR3IN (P_PX01)

SR2IO (P_PX06)

NVMCLK (PA7)

NVMDATA (PE3)

A10

A11

A12

A13

A14

A15

A16 (PB0)

A17 (PB4)

A18 (PB5)

WRITE#

READ#

ROMSEL# (PB2)

RAMSEL# (PB3)

EXT_RES# (PB6)

PLLVDD

PLLGND

105

106

118

119

102

104

107

EEPROM

(OPTIONAL)

100491_F3-1_HI_88168 128T PAR

+3.3V

CX88168

MODEM SINGLE

CHIP

MODEM

(SCM)

128-PIN TQFP

PARALLEL

INTERFACE

(PARIF = HIGH)

+3.3V

DIGITAL ISOLATION

BARRIER (DIB)

1uF

+3.3V

CRYSTAL

CIRCUIT

GSM PHONE

EXTERNAL MEMORY

(OPTIONAL)

LINE/CELL SELECT

LINE/GSM SELECT

GSMRXD

GSMTXD

GSMINPO

RXPAD#

TXPAD#

CELCLK

CELDATA

CELBSY

CELBSY#

RXPAD#

TXPAD#

CELL PHONE

SPEAKER CIRCUIT

CX20437

VOICE CODEC (VC)

(OPTIONAL)

SLEEP

M_CLKIN

M_SCK

M_STROBE

M_TXSIN

M_RXOUT

M_CNTRLSIN

+3.3V or +5V

VOICE#

HS_LCS

DAA

Figure 3-1. CX88168 SCM Hardware Signals for Parallel Interface (PARIF = High)

SmartSCM Modem Data Sheet

3-4 Conexant 100490C

100491_F3-2_PO_88168 128T PA R

102

101

100

128

127

126

125

124

123

122

121

120

119

118

117

116

115

114

113

112

111

110

109

108

107

106

105

104

103

GND

HD4 (PC4)

HD3 (PC3)

HD2 (PC2)

VDD

HD1 (PC1)

HD0 (PC0)

PHS2

GND

READ#

WRITE#

NMI#

VDD

XTLO

XTLI

CLKIN

GND

DV1TP

TESTP

HINT (PB7)

VDD

EXT_RES# (PB6)

A18 (PB5)

A17 (PB4)

RAMSEL# (PB3)

GND

SR2IO (P_PX06)

VDD

P_PX00

P_PX02

P_PX03

GND

SR4IN

PD7

NOXYCK

GND

XCLK

IASLEEP (P_PF05)

RESERVED (P_PB01)

RESERVED (GP00)

VDD

RESERVED (P_PA04)

RESERVED (P_PA00)

RESERVED (P_PA05)

RESERVED (P_PA01)

VDD

RESERVED (BD2CLK)

VGG

CLKOUT

ROMSEL# (PB2)

RESERVED (PB1)

VDD

A16 (PB0)

DSPKOUT

PWRCLKN

PWRCLKP

GND

DIB_DATAN

DIB_DATAP

SR2CLK (P_PGP05)

A15

GND

A14

A13

A12

A11

VDD

A10

PLLGND

PLLVDD

VDD

GND

HD5 (PC5)

VDD

HD6 (PC6)

HD7 (PC7)

PARIF

HA0 (PD0)

HA1 (PD1)

HA2 (PD2)

STPMODE# (PD3)

GND

HCS# (PD4)

HWT# (PD5)

HRD# (PD6)

RXPAD# (PE0)

VDD

VOICE#/TXPAD# (PE1)

CELBSY (PE2)

NVMDATA (PE3)

HS_LCS (PE4)

VDD

CELDATA (PE5)

SSD_RING# (PE6)

LINE/CELL (PE7)

SSD_RINGWAKE (PA0)

GND

SSD_INT (PA1)

GSMRXD (PA2)

CELBSY# (PA3)

CELCLK/GSMINP0 (PA4)

GND

LINE/GSM (PA5)

GSMTXD (PA6)

NVMCLK (PA7)

RESET#

SR3OUT

SR3IN (P_PX01)

M_CLK (P_PB00)

SA2CLK (P_PX05)

CX88168

PARALLEL INTERFACE

(PARIF PIN = HIGH)

Figure 3-2. CX88168 SCM 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High)

SmartSCM Modem Data Sheet

100490C Conexant 3-5

Table 3-1. CX88168 SCM 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High)

Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface

1 HD5 (PC5) I/O Ith/Ot8 HB: HD5 65 D3 I/O Ith/Ot2 EB: D3

2 VDD P PWR +3.3V 66 D4 I/O Ith/Ot2 EB: D4

3 HD6 (PC6) I/O Ith/Ot8 HB: HD6 67 D5 I/O Ith/Ot2 EB: D5

4 HD7 (PC7) I/O Ith/Ot8 HB: HD7 68 GND G GND GND

5 PARIF I Itpu NC (parallel interface) 69 D6 I/O Ith/Ot2 EB: D6

6 HA0 (PD0) I Ithpd/Ot2 HB: HA0 70 D7 I/O Ith/Ot2 EB: D7

7 HA1 (PD1) I Ithpd/Ot2 HB: HA1 71 A0 O It/Ot8 EB: A0

8 HA2 (PD2) I Ithpd/Ot2 HB: HA2 72 A1 O It/Ot8 EB: A1

9 STPMODE# (PD3) I Ith/Ot2 NC 73 A2 O It/Ot8 EB: A2

10 GND G GND GND 74 A3 O It/Ot8 EB: A3

11 HCS# (PD4) I It HB: CS# 75 A4 O It/Ot8 EB: A4

12 HWT# (PD5) I Ithpu HB: WT# 76 A5 O It/Ot8 EB: A5

13 HRD# (PD6) I Ithpu HB: RD# 77 A6 O It/Ot8 EB: A6

14 RXPAD# (PE0) O It/Ot8 CELL/GSM: RXPAD# 78 VDD P PWR +3.3V

15 VDD P PWR +3.3V 79 A7 O It/Ot8 EB: A7

16 VOICE#/TXPAD#

(PE1)

O It/Ot2 DAA: VOICE#;

CELL/GSM:TXPAD#

80 A8 O It/Ot8 EB: A8

17 CELBSY (PE2) O It/Ot2 CELL: CELBSY 81 A9 O It/Ot8 EB: A9

18 NVMDATA (PE3) I/O It/Ot2 NVRAM: SDA 82 PLLVDD P PWR +3.3V and GND through

1 uF

19 HS_LCS (PE4) I It/Ot2 GND through 47 KΩ83 PLLGND G GND GND

20 VDD P PWR +3.3V 84 A10 O It/Ot8 EB: A10

21 CELDATA (PE5) I/O It/Ot2 CELL: CEL_DATA 85 VDD P PWR +3.3V

22 SSD_RING# (PE6) O It/Ot2 NC 86 A11 O It/Ot8 EB: A11

23 LINE/CELL (PE7) I It/Ot8 Line/Cell select 87 A12 O It/Ot8 EB: A12

24 SSD_RINGWAKE

(PA0)

O It/Ot2 NC 88 A13 O It/Ot8 EB: A13

25 GND G GND GND 89 A14 O It/Ot8 EB: A14

26 SSD_INT (PA1) O It/Ot2 NC 90 GND G GND GND

27 GSMRXD (PA2) I/O It/Ot2 GSM: GSMRXD 91 A15 O It/Ot8 EB: A15

28 CELBSY# (PA3) I Itpu/Ot2 CELL: CELBSY# 92 SR2CLK (P_PGP05) I Itpu/Ot2 VC: M_SCK

29 CELCLK/GSMINP0

(PA4)

I Itpu/Ot2 CELL: CELCLK;

GSM: GSMINP0

93 DIB_DATAP I/O Idd/Odd DIB: Data Pos. Channel

30 GND G GND GND 94 DIB_DATAN I/O Idd/Odd DIB: Data Neg. Channel

31 LINE/GSM (PA5) I It/Ot2 Line/GSM select 95 GND G GND GND

32 GSMTXD (PA6) I/O It/Ot2 GSM: GSMTXD 96 PWRCLKP O Odpc DIB: Transformer

primary winding non-

dotted terminal

33 NVMCLK (PA7) O It/Ot2 NVRAM: SCL 97 PWRCLKN O Odpc DIB: Transformer

primary winding dotted

terminal

34 RESET# I It HB: RESET# 98 DSPKOUT O It/Ot2 Speaker Circuit

35 SR3OUT O Ot2 VC: M_TXSIN 99 A16 (PB0) O It/Ot2 EB: A16

36 SR3IN (P_PX01) I Itk/Ot2 VC: M_RXOUT 100 VDD P PWR +3.3V

37 M_CLK (P_PB00) O It/Ot2 VC: M_CLKIN 101 RESERVED (PB1) O It/Ot2 NC

38 SA2CLK (P_PX05) I Itpu/Ot2 VC: M_STROBE 102 ROMSEL# (PB2) O Ot2 EB: ROM CE#

39 SR2IO (P_PX06) O It/Ot2 VC: M_CNTRLSIN 103 GND G GND GND

40 VDD P PWR +3.3V 104 RAMSEL# (PB3) O It/Ot2 EB: RAM CS#

41 P_PX00 I/O It/Ot8 NC 105 A17 (PB4) O It/Ot2 EB: A17

42 P_PX02 I/O Itpu/Ot2 NC 106 A18 (PB5) O It/Ot2 EB: A18

43 P_PX03 I/O Itpu/Ot2 NC 107 EXT_RES# (PB6) O It/Ot2 NC

44 GND G GND GND 108 VDD P PWR +3.3V

45 SR4IN I Itk NC 109 HINT (PB7) O It/Ot8 HB: HINT

46 PD7 I/O It/Ot2 NC 110 TESTP I Itpu NC

47 NOXYCK I Itpu GND 111 DV1TP I Itpu NC

48 GND G GND GND 112 GND G GND GND

49 XCLK O It/Ot2 NC 113 CLKIN I It NC

50 IASLEEP (P_PF05) O Ot2 VC: SLEEP 114 XTLI I Ix Crystal Circuit

SmartSCM Modem Data Sheet

3-6 Conexant 100490C

Table 3-1. CX88168 SCM 128-Pin TQFP Pin Signals for Parallel Interface (PARIF = High) (Continued)

Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface

51 RESERVED (P_PB01) I/O Itpu/Ot2 NC 115 XTLO O Ox Crystal Circuit

52 RESERVED (GP00) I/O It/Ot2 NC 116 VDD P PWR +3.3V

53 VDD P PWR +3.3V 117 NMI# I Ithpu +3.3V

54 RESERVED (P_PA04) I/O Itpu/Ot2 NC 118 WRITE# O It/Ot2 EB: WRITE#

55 RESERVED (P_PA00) I/O Itpu/Ot2 NC 119 READ# O It/Ot2 EB: READ#

56 RESERVED (P_PA05) I/O Itk/Ot2 NC 120 GND G GND GND

57 RESERVED (P_PA01) I/O Itpu/Ot2 NC 121 PHS2 O Ot2 NC

58 VDD P PWR +3.3V 122 HD0 (PC0) I/O Ith/Ot8 HB: HD0

59 RESERVED

(BD2CLK)

O Itpu/Ot2 NC 123 HD1 (PC1) I/O Ith/Ot8 HB: HD1

60 VGG P PWRG +3.3V or +5V 124 VDD P PWR +3.3V

61 CLKOUT O It/Ot2 NC 125 HD2 (PC2) I/O Ith/Ot8 HB: HD2

62 D0 I/O Ith/Ot2 EB: D0 126 HD3 (PC3) I/O Ith/Ot8 HB: HD3

63 D1 I/O IthOt2 EB: D1 127 HD4 (PC4) I/O Ith/Ot8 HB: HD4

64 D2 I/O Ith/Ot2 EB: D2 128 GND G GND GND

Notes:

1. I/O Types: See Table 3-5.

2. Interface Legend:

DIB Digital Isolation Barrier

EB Expansion Bus

HB Host Bus

NC No internal pin connection

VC Voice Codec

SmartSCM Modem Data Sheet

100490C Conexant 3-7

Table 3-2. CX88168 SCM Pin Signal Definitions for Parallel Interface (PARIF = High)

Label Pin I/O I/O Type Signal Name/Description

System

XTLI,

XTLO

114,

115

Ix,

Crystal In and Crystal Out. If an external 28.224 MHz crystal circuit is used

instead of an external clock circuit, connect XTLI and XTLO to the external

crystal circuit and leave CLKIN open.

CLKIN 113 I It Clock In. If an external 28.224 MHz clock circuit is used instead of an

external crystal circuit, connect CLKIN to the clock output and leave XTLI

and XTLO open.

CLKOUT 61 O It/Ot2 Clock Out. 28.224 MHz output clock. Leave open.

PARIF 5 I Itpu Parallel/Serial Interface Select. PARIF input high (open) selects parallel

host interface operation (see this table); PARIF low (GND) selects serial

DTE interface operation (see Table 3-4).

STPMODE# (PD3) 9 I Ith/Ot2 Stop Mode. Not used. Leave open.

NMI# 117 I Ithpu Non-Maskable Interrupt. Not used. Connect to +3.3V.

RESET# 34 I It Reset. The active low RESET# input resets the SCM logic, and restores the

saved configuration from serial EEPROM or returns the modem to the

factory default values if NVRAM is not present.

RESET# low holds the modem in the reset state; RESET# going high

releases the modem from the reset state. After application of VDD, RESET#

must be held low for at least 15 ms after the VDD power reaches operating

range. The modem device set is ready to use 25 ms after the low-to-high

transition of RESET#.

For parallel Interface, connect RESET# input to the host bus RESET line

through an inverter.

VGG 60 P PWRG I/O Signaling Voltage Source. Connect to +3.3V for +3.3V inputs or +5V

for +5V inputs.

VDD 2, 15, 20, 40,

53, 58, 78,

85, 100, 108,

116, 124

PPWRDigital Supply Voltage. Connect to VCC (+3.3V, filtered).

GND 10, 25, 30,

44, 48, 68,

90, 95, 103,

112, 120,

128

GGND Digital Ground. Connect to digital ground (GND).

SSD_RING# (PE6) 22 O It/Ot2 SmartDAA Raw Ring. A toggling edge used to indicate presence of a ring

frequency. The idle state (no ringing) output of the ring detect circuit is high.

SSD_INT (PA1) 26 O It/Ot2 SmartDAA Interface Interrupt. Active low output used to indicate to the host

when the SmartDAA Interface needs servicing.

SSD_RINGWAKE

(PA0)

24 O It/Ot2 SmartDAA Ring Wake. Active high output used to indicate to the host that a

valid ring or line polarity reversal has been detected.

PLLVDD 82 P PWR PLL Circuit Digital Supply Voltage. Connect to +3.3V and to GND through

1 µF.

PLLGND 83 G GND PLL Circuit Digital Ground. Connect to GND.

Serial EEPROM (NVRAM) Interface

NVMCLK (PA7) 33 O It/Ot2 NVRAM Clock. NVMCLK output high enables the EEPROM. Connect to

EEPROM SCL pin.

NVMDATA (PE3) 18 I/O It/Ot2 NVRAM Data. The NVMDATA pin supplies a serial data interface to the

EEPROM. Connect to EEPROM SDA pin and to +3.3V through 10 KΩ.

SmartSCM Modem Data Sheet

3-8 Conexant 100490C

Table 3-2. CX88168 SCM Pin Signal Definitions for Parallel Interface (PARIF = High) (Continued)

Label Pin I/O I/O Type Signal Name/Description

Speaker Interface

DSPKOUT 98 O It/Ot2 Modem Speaker Digital Output. The DSPKOUT digital output reflects the

received analog input signal digitized to TTL high or low level by an internal

comparator.

DIB Interface

PWRCLKP 96 O Odpc Clock and Power Positive. Provides clock and power to the LSD. Connect

to DIB transformer primary winding non-dotted terminal.

PWRCLKN 97 O Odpc Clock and Power Negative. Provides clock and power to the LSD. Connect

to DIB transformer primary winding dotted terminal.

DIB_DATAP 93 I/O Idd/Odd Data Positive. Transfers data, control, and status information between the

SCM and the LSD. Connect to LSD through DIB data positive channel

components.

DIB_DATAN 94 I/0 Idd/Odd Data Negative. Transfers data, control, and status information between the

SCM and the LSD. Connect to LSD through DIB data negative channel

components.

External Bus Interface

A0-A9,

A10-A15,

A16 (PB0),

A17 (PB4),

A18 (PB5)

71-77, 79-81,

84, 86-89, 91,

99,

105,

106

It/Ot8,

It/Ot2,

It/Ot2

Address Lines 0-18. A0-A18 are the address output lines used to access

optional external memory; up to 4 Mbits (512k bytes) ROM/flash ROM using

A0-A18 and up to 1 Mbit (128k bytes) RAM using A0-A16.

If internal ROM is used for the 256k-byte base modem ROM code and

external ROM/flash ROM is used only for the additional GSM ROM code, the

128k-byte GSM ROM code is located in the upper-most portion of the 512k-

byte address range with A17 used as GSM ROM select.

If external ROM/flash ROM is used for the base modem ROM, the 256k-byte

base modem ROM code is located in the 0-256k-byte address range. If

included, the 128k-byte GSM ROM code is located in the upper-most portion

of the 512k-byte address range.

D0-D7 62-67, 69-70 I/O Ith/Ot2 Data Line 0-7. D0-D7 are the bidirectional external memory bus data lines.

READ# 119 O It/Ot2 Read Enable. READ# output low enables data transfer from the selected

device to the D0-D7 lines.

WRITE# 118 O It/Ot2 Write Enable. WRITE# output low enables data transfer from the D0-D7

lines to the selected device.

ROMSEL# (PB2) 102 O Ot2 ROM Select. ROMSEL# (PB2, ES3) output low selects the external

ROM/flash ROM.

RAMSEL# (PB3) 104 O It/Ot2 RAM Select. RAMSEL#, PB3 (ES2) output low selects the external RAM.

RESERVED (PB1) 101 O It/Ot2 Reserved. PB1 (ES4) is used internally. Leave open.

EXT_RES# (PB6) 107 O It/Ot2 External Device Reset. Active low reset for external devices. Leave open if

not used.

CX20437 VC Interface

IASLEEP (P_PF05) 50 O Ot2 Modem Sleep. Connect to VC SLEEP pin.

M_CLK (P_PB00) 37 O It/Ot2 Master Clock Output. Connect to VC M_CLKIN pin.

SR2CLK (P_PGP05) 92 I Itpu/Ot2 Voice Serial Clock input. Connect to VC M_SCK pin.

SA2CLK (P_PX05) 38 I Itpu/Ot2 Voice Serial Frame Sync Input. Connect to VC M_STROBE pin.

SR3OUT 35 O Ot2 Voice Serial Transmit Data Output. Connect to VC M_TXSIN pin.

SR3IN (P_PX01) 36 I Itk/Ot2 Voice Serial Receive Data Input. Connect to VC M_RXOUT pin.

SR2IO (P_PX06) 39 O It/Ot2 Voice Control Output. Connect to VC M_CNTRLSIN pin.

SmartSCM Modem Data Sheet

100490C Conexant 3-9

Table 3-2. CX88168 SCM Pin Signal Definitions for Parallel Interface (PARIF = High) (Continued)

Label Pin I/O I/O Type Signal Name/Description

Telephone Line/Analog Cellular Phone/GSM Phone Interface Select

LINE/GSM (PA5) 31 I It/Ot2 Line/GSM Interface Select. In conjunction with the LINE/CELL input,

selects telephone line, cellular phone (AMPS), or GSM phone interface.

LINE/CELL (PE7) 23 I It/Ot8 Line/Cellar Interface Select. In conjunction with the LINE/GSM input,

selects telephone line, cellular phone (AMPS), or GSM phone interface, as

follows:

LINE/CELL LINE/GSM Interface Selected

H H Telephone Line

L H Cellular (AMPS)

HL GSM

L L Invalid

The following ports operate as indicated for the selected interface:

Port Telephone Line Analog Cellular GSM

PE0 — RXPAD# RXPAD#

PE1 VOICE# TXPAD# TXPAD#

PE2 — CELBSY —

PE5 — CELDATA —

PA2 — — GSMRXD

PA3 — CELBSY# —

PA4 — CELCLK GSMINP0

PA6 — — GSMTXD

Note: Ports marked “—“ are not used.

Parallel Host Interface

HCS# (PD4) 11 I It Host Bus Chip Select. HCS# input low enables the MCU host bus

interface.

HWT# (PD5) 12 I Ithpu Host Bus Write. HWT# is an active low, write control input. When HCS# is

low, HWT# low allows the host to write data or control words into a selected

MCU register.

HRD# (PD6) 13 I Ithpu Host Bus Read. HRD# is an active low, read control input. When HCS# is

low, HRD# low allows the host to read status information or data from a

selected MCU register.

HINT (PB7) 109 O It/Ot8 Host Bus Interrupt. HINT output is set high when the receiver error flag,

received data available, transmitter holding register empty, or modem

status interrupt is asserted. HINT is reset low upon the appropriate interrupt

service or master reset operation.

HA0-HA2

(PD0-PD2)

6-8 I Ithpd/Ot2 Host Bus Address Lines 0-2. During a host read or write operation with

HCS# low, HA0-HA2 select an internal MCU 16550A-compatible register.

HD0-HD7

(PC0-PC7)

122-123,

125-127, 1,

3-4

I/O Ith/Ot8 Host Bus Data Lines 0-7. HD0-HD7 are three-state input/output lines

providing bidirectional communication between the host and the MCU.

Data, control words, and status information are transferred over HD0-HD7.

Analog Cellular Phone Interface (LINE/CELL = Low and LINE/GSM = High)

CELCLK/GSMINP0

(PA4)

29 I Itpu/Ot2 Cellular Clock. Defined by the cellular firmware driver.

CELDATA (PE5) 21 I/O It/Ot2 Cellular Data. Defined by the cellular firmware driver.

CELBSY (PE2) 17 O It/Ot2 Cellular Busy. Defined by the cellular firmware driver.

CELBSY# (PA3) 28 I Itpu/Ot2 Cellular Not Busy. Defined by the cellular firmware driver.

RXPAD# (PE0) 14 O It/Ot8 Cellular RX Bias. Defined by the cellular firmware driver.

VOICE#/TXPAD#

(PE1)

16 O It/Ot2 Cellular TX Bias. Defined by the cellular firmware driver.

SmartSCM Modem Data Sheet

3-10 Conexant 100490C

Table 3-2. CX88168 SCM Pin Signal Definitions for Parallel Interface (PARIF = High) (Continued)

Label Pin I/O I/O Type Signal Name/Description

Telephone Interface (LINE/CELL = High and LINE/GSM = High)

VOICE#/TXPAD# (PE1) 16 O It/Ot2 Voice Relay Control. When the LINE/CELL input is high, this output

(typically active low) used to control the normally open voice relay. See

cellular interface signals for TXPAD# usage.

HS_LCS (PE4) 19 I It/Ot2 Handset Line Current Sense. LCS is an active high input that indicates a

handset off-hook status. Not required for data/fax/voice/speakerphone

operation. If not used, connect to GND through 47 KΩ.

GSM Cellular Phone Interface (LINE/CELL = High and LINE/GSM = Low)

CELCLK/GSMINP0

(PA4)

29 I Itpu/Ot2 GSM Input Control. Defined by the GSM firmware driver.

GSMRXD (PA2) 27 I It/Ot2 GSM Serial Receive Data. Defined by the GSM firmware driver.

GSMTXD (PA6) 32 O It/Ot2 GSM Serial Transmit Data. Defined by the GSM firmware driver.

RXPAD# (PE0) 14 O It/Ot8 GSM RX Bias. Defined by the GSM firmware driver.

VOICE#/TXPAD#

(PE1)

16 O It/Ot2 GSM TX Bias. Defined by the GSM firmware driver.

Not Used

NOXYCK 47 I Itpu Disable XCLK Output. When low, disables XCLK output (reduces internal

power consumption). When high, enables XCLK output. Connect to GND.

TESTP 110 I Itpu Test. Used for factory test only. Leave open.

DV1TP 111 I Itpu Test. Used for factory test only. Leave open.

XCLK 49 O It/Ot2 Not Used. Leave open.

PHS2 121 O Ot2 Not Used. Leave open.

SR4RIN 45 I Itk Not Used. Leave open.

PD7 46 I/O It/Ot2 Not Used. Leave open.

P_PX00 41 I/O It/Ot8 Not Used. Leave open.

P_PX02 42 I/O Itpu/Ot2 Not Used. Leave open.

P_PX03 43 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (GP00) 52 I/O It/Ot2 Not Used. Leave open.

RESERVED (P_PA00) 55 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (P_PA01) 57 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (P_PA04) 54 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (P_PA05) 56 I/O Itk/Ot2 Not Used. Leave open.

RESERVED (P_PB01) 51 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED

(P_BD2CLK)

59 I/O Itpu/Ot2 Not Used. Leave open.

Notes:

1. I/O Types: See Table 3-5.

2. Interface Legend:

DIB Digital Isolation Barrier

EB Expansion Bus

HB Host Bus

NC No internal pin connection

VC Voice Codec

RESERVED = No external connection allowed (may have internal connection).

SmartSCM Modem Data Sheet

100490C Conexant 3-11

XTLI

XTLO

CLKIN

CLKOUT

XCLK

RESERVED (P_PA01)

NOXYCK

PARIF

STPMODE# (PD3)

NMI#

RESET#

AAIND# (PC4)

TMIND# (PB7)

DTRIND# (PD0)

TXD# (PA2)

RXD# (PA6)

CTS# (PC1)

DSR# (PC0)

RLSD# (PC2)

TM# (PC6)

RI# (PC5)

DTR# (PD4)

RTS# (PD6)

RESERVED (P_PB01)

RESERVED (P_PA05)

RESERVED (P_GP00)

SSD_RINGWAKE (PA0)

SSD_RING# (PE6)

SSD_INT (PA1)

TESTP

DV1TP

PHS2

SR4IN

PC3

PD1

PD2

PD7

RESERVED (PB1)

RESERVED (PC7)

RESERVED (PD5)

RESERVED (P_PA00)

RESERVED (P_PA05)

RESERVED (BD2CLK)

P_PX00

P_PX02

P_PX03

VGG

VDD

GND

114

115

113

117

127

109

123

122

125

110

111

121

126

101

100

108

116

124

103

112

120

128

SERIAL DTE

INTERFACE

LINE/CELL (PE7)

LINE/GSM (PA5)

CELCLK(PA4)

CELDATA (PE5)

CELBSY (PE2)

CELBSY# (PA3)

OHIND#/RXPAD# (PE0)

VOICE#/TXPAD# (PE1)

HS_LCS (PE4)

DSPKOUT

PWRCLKP

PWRCLKN

DIB_DATAP

DIB_DATAN

IASLEEP (P_PF05)

M_CLK (P_PB00)

SR2CLK (P_PGP05)

SA2CLK (P_PX05)

SR3OUT

SR3IN (P_PX01)

SR2IO (P_PX06)

NVMCLK (PA7)

NVMDATA (PE3)

A10

A11

A12

A13

A14

A15

A16 (PB0)

A17 (PB4)

A18 (PB5)

WRITE#

READ#

ROMSEL# (PB2)

RAMSEL# (PB3)

EXT_RES# (PB6)

PLLVDD

PLLGND

105

106

118

119

102

104

107

EEPROM (OPTIONAL)

100489_F3-3_HI_81300 128T SER

+3.3V

CX88168

MODEM SINGLE

CHIP

MODEM

(SCM)

128-PIN TQFP

SERIAL

INTERFACE

(PARIF = LOW)

+3.3V

DIGITAL ISOLATION

BARRIER (DIB)

1uF

CRYSTAL

CIRCUIT

EXTERNAL MEMORY

(OPTIONAL)

LED

INTERFACE

RESET CIRCUIT

SPEAKER CIRCUIT

SLEEP

M_CLKIN

M_SCK

M_STROBE

M_TXSIN

M_RXOUT

M_CNTRLSIN

LINE/CELL SELECT

CELCLK

CELDATA

CELBSY

CELBSY#

RXPAD#

TXPAD#

OHIND#

CELL PHONE

LED INDICATOR

+3.3V OR +5V

VOICE#

HS_LCS

CX20437

VOICE CODEC (VC)

(OPTIONAL)

+3.3V DAA

Figure 3-3. CX88168 SCM Hardware Signals for Serial Interface (PARIF = Low)

SmartSCM Modem Data Sheet

3-12 Conexant 100490C

100491_F3-4_PO_88168 128T_SER

102

101

100

128

127

126

125

124

123

122

121

120

119

118

117

116

115

114

113

112

111

110

109

108

107

106

105

104

103

GND

AAIND# (PC4)

DRSOUT# (PC3)

RLSD# (PC2)

VDD

CTS# (PC1)

DSR# (PC0)

PHS2

GND

READ#

WRITE#

NMI#

VDD

XTLO

XTLI

CLKIN

GND

DV1TP

TESTP

TMIND# (PB7)

VDD

EXT_RES# (PB6)

A18 (PB5)

A17 (PB4)

RAMSEL# (PB3)

GND

SR2IO (P_PX06)

VDD

P_PX00

P_PX02

P_PX03

GND

SR4IN

PD7

NOXYCK

GND

XCLK

IASLEEP (P_PF05)

RESERVED (P_PB01)

RESERVED (GP00)

VDD

RESERVED (P_PA04)

RESERVED (P_PA00)

RESERVED (P_PA05)

RESERVED (P_PA01)

VDD

RESERVED (BD2CLK)

VGG

CLKOUT

ROMSEL# (PB2)

RESERVED (PB1)

VDD

A16 (PB0)

DSPKOUT

PWRCLKN

PWRCLKP

GND

DIB_DATAN

DIB_DATAP

SR2CLK (P_PGP05)

A15

GND

A14

A13

A12

A11

VDD

A10

PLLGND

PLLVDD

VDD

GND

RI# (PC5)

VDD

TM# (PC6)

RESERVED (PC7)

PARIF

DTRIND# (PD0)

PD1

PD2

STPMODE# (PD3)

GND

DTR# (PD4)

RESERVED (PD5)

RTS# (PD6)

OHIND#/RXPAD# (PE0)

VDD

VOICE#/TXPAD# (PE1)

CELBSY (PE2)

NVMDATA (PE3)

HS_LCS (PE4)

VDD

CELDATA (PE5)

SSD_RING# (PE6)

LINE/CELL (PE7)

SSD_RINGWAKE (PA0)

GND

SSD_INT (PA1)

TXD# (PA2)

CELBSY# (PA3)

CELCLK (PA4)

GND

LINE/GSM (PA5)

RXD# (PA6)

NVMCLK (PA7)

RESET#

SR3OUT

SR3IN (P_PX01)

M_CLK (P_PB00)

SA2CLK (P_PX05)

CX88168

SERIAL INTERFACE

(PARIF PIN = LOW)

Figure 3-4. CX88168 SCM 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low)

SmartSCM Modem Data Sheet

100490C Conexant 3-13

Table 3-3. CX88168 SCM 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low)

Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface

1 RI# (PC5) O Ith/Ot8 DTE IF: RI# 65 D3 I/O Ith/Ot2 EB: D3

2 VDD P PWR +3.3V 66 D4 I/O Ith/Ot2 EB: D4

3 TM# (PC6) O Ith/Ot8 DTE IF: TM# 67 D5 I/O Ith/Ot2 EB: D5

4 RESERVED (PC7) I Ith/Ot8 +3.3V through 47K Ω68 GND G GND GND

5 PARIF I Itpu GND (serial interface) 69 D6 I/O Ith/Ot2 EB: D6

6 DTRIND# (PD0) O Ithpd/Ot2 LED: DTRIND# 70 D7 I/O Ith/Ot2 EB: D7

7 PD1 I/O Ithpd/Ot2 NC 71 A0 O It/Ot8 EB: A0

8 PD2 I/O Ithpd/Ot2 NC 72 A1 O It/Ot8 EB: A1

9 STPMODE# (PD3) I Ith/Ot2 NC 73 A2 O It/Ot8 EB: A2

10 GND G GND GND 74 A3 O It/Ot8 EB: A3

11 DTR# (PD4) I It DTE IF: DTR# 75 A4 O It/Ot8 EB: A4

12 RESERVED (PD5) I Ithpu NC 76 A5 O It/Ot8 EB: A5

13 RTS# (PD6) I Ithpu DTE IF: RTS# 77 A6 O It/Ot8 EB: A6

14 OHIND#/RXPAD#

(PE0)

O It/Ot8 LED: OHIND#

CELL: RXPAD#

78 VDD P PWR +3.3V

15 VDD P PWR +3.3V 79 A7 O It/Ot8 EB: A7

16 VOICE#/

TXPAD# (PE1)

O It/Ot2 DAA: VOICE#;

CELL:TXPAD#

80 A8 O It/Ot8 EB: A8

17 CELBSY (PE2) O It/Ot2 CELL: CELBSY 81 A9 O It/Ot8 EB: A9

18 NVMDATA (PE3) I/O It/Ot2 NVRAM: SDA 82 PLLVDD P PWR +3.3V and GND through

1 uF

19 HS_LCS (PE4) I It/Ot2 GND through 47 KΩ83 PLLGND G GND GND

20 VDD P PWR +3.3V 84 A10 O It/Ot8 EB: A10

21 CELDATA (PE5) I/O It/Ot2 CELL: CEL_DATA 85 VDD P PWR +3.3V

22 SSD_RING# (PE6) O It/Ot2 NC 86 A11 O It/Ot8 EB: A11

23 LINE/CELL (PE7) I It/Ot8 Line/Cell select 87 A12 O It/Ot8 EB: A12

24 SSD_RINGWAKE

(PA0)

O It/Ot2 NC 88 A13 O It/Ot8 EB: A13

25 GND G GND GND 89 A14 O It/Ot8 EB: A14

26 SSD_INT (PA1) O It/Ot2 NC 90 GND G GND GND

27 TXD# (PA2) I It/Ot2 DTE IF: TXD# 91 A15 O It/Ot8 EB: A15

28 CELBSY# (PA3) I Itpu/Ot2 CELL: CELBSY# 92 SR2CLK (P_PGP05) I Itpu/Ot2 VC: M_SCK

29 CELCLK/GSMINP0

(PA4)

I Itpu/Ot2 CELL: CELCLK 93 DIB_DATAP I/O Idd/Odd DIB: Data Pos. Channel

30 GND G GND GND 94 DIB_DATAN I/O Idd/Odd DIB: Data Neg. Channel

31 LINE/GSM (PA5) I It/Ot2 NC 95 GND G GND GND

32 RXD# (PA6) O It/Ot2 DTE IF: RXD# 96 PWRCLKP O Odpc DIB: Transformer

primary winding non-

dotted terminal

33 NVMCLK (PA7) O It/Ot2 NVRAM: SCL 97 PWRCLKN O Odpc DIB: Transformer

primary winding dotted

terminal

34 RESET# I It Reset Circuit 98 DSPKOUT O It/Ot2 Speaker Circuit

35 SR3OUT O Ot2 VC: M_TXSIN 99 A16 (PB0) O It/Ot2 EB: A16

36 SR3IN (P_PX01) I Itk/Ot2 VC: M_RXOUT 100 VDD P PWR +3.3V

37 M_CLK (P_PB00) O It/Ot2 VC: M_CLKIN 101 RESERVED (PB1) O It/Ot2 NC

38 SA2CLK (P_PX05) I Itpu/Ot2 VC: M_STROBE 102 ROMSEL# (PB2) O Ot2 EB: ROM CE#

39 SR2IO (P_PX06) O It/Ot2 VC: M_CNTRLSIN 103 GND G GND GND

40 VDD P PWR +3.3V 104 RAMSEL# (PB3) O It/Ot2 EB: RAM CS#

41 P_PX00 I/O It/Ot8 NC 105 A17 (PB4) O It/Ot2 EB: A17

42 P_PX02 I/O Itpu/Ot2 NC 106 A18 (PB5) O It/Ot2 EB: A18

43 P_PX03 I/O Itpu/Ot2 NC 107 EXT_RES# (PB6) O It/Ot2 NC

44 GND G GND GND 108 VDD P PWR +3.3V

45 SR4IN I Itk NC 109 TMIND# (PB7) O It/Ot8 LED: TMIND#

46 PD7 I/O It/Ot2 NC 110 TESTP I Itpu NC

47 NOXYCK I Itpu GND 111 DV1TP I Itpu NC

48 GND G GND GND 112 GND G GND GND

49 XCLK O It/Ot2 NC 113 CLKIN I It NC

50 IASLEEP (P_PF05) O Ot2 VC: SLEEP 114 XTLI I Ix Crystal Circuit

SmartSCM Modem Data Sheet

3-14 Conexant 100490C

Table 3-3. CX88168 SCM 128-Pin TQFP Pin Signals for Serial Interface (PARIF = Low) (Continued)

Pin Signal Label I/O I/O Type Interface Pin Signal Label I/O I/O Type Interface

51 RESERVED (P_PB01) I/O Itpu/Ot2 NC 115 XTLO O Ox Crystal Circuit

52 RESERVED (GP00) I/O It/Ot2 NC 116 VDD P PWR +3.3V

53 VDD P PWR +3.3V 117 NMI# I Ithpu +3.3V

54 RESERVED (P_PA04) I/O Itpu/Ot2 NC 118 WRITE# O It/Ot2 EB: WRITE#

55 RESERVED (P_PA00) I/O Itpu/Ot2 NC 119 READ# O It/Ot2 EB: READ#

56 RESERVED (P_PA05) I/O Itk/Ot2 NC 120 GND G GND GND

57 RESERVED (P_PA01) I/O Itpu/Ot2 NC 121 PHS2 O Ot2 NC

58 VDD P PWR +3.3V 122 DSR# (PC0) I/O Ith/Ot8 DTE IF: DSR#

59 RESERVED

(BD2CLK)

O Itpu/Ot2 NC 123 CTS# (PC1) I/O Ith/Ot8 DTE IF: CTS#

60 VGG P PWRG +3.3V or +5V 124 VDD P PWR +3.3V

61 CLKOUT O It/Ot2 NC 125 RLSD# (PC2) I/O Ith/Ot8 DTE IF: RLSD#

62 D0 I/O Ith/Ot2 EB: D0 126 PC3 I/O Ith/Ot8 NC

63 D1 I/O IthOt2 EB: D1 127 AAIND# (PC4) O Ith/Ot8 LED: AAIND#

64 D2 I/O Ith/Ot2 EB: D2 128 GND G GND GND

Notes:

1. I/O Types: See Table 3-5.

2. Interface Legend:

DIB Digital Isolation Barrier

EB Expansion Bus

HB Host Bus

NC No internal pin connection

VC Voice Codec

SmartSCM Modem Data Sheet

100490C Conexant 3-15

Table 3-4. CX88168 SCM Pin Signal Definitions for Serial Interface (PARIF = Low)

Label Pin I/O I/O Type Signal Name/Description

System

XTLI,

XTLO

114,

115

Ix,

Crystal In and Crystal Out. If an external 28.224 MHz crystal circuit is used

instead of an external clock circuit, connect XTLI and XTLO to the external

crystal circuit and leave CLKIN open.

CLKIN 113 I It Clock In. If an external 28.224 MHz clock circuit is used instead of an

external crystal circuit, connect CLKIN to the clock output and leave XTLI

and XTLO open.

CLKOUT 61 O It/Ot2 Clock Out. 28.224 MHz output clock. Leave open.

PARIF 5 I Itpu Parallel/Serial Interface Select. PARIF input high (open) selects parallel

host interface operation (see signal definitions in Table 3-2); PARIF low

(GND) selects serial DTE interface operation (see signal definitions in this

table).

STPMODE# (PD3) 9 I Ith/Ot2 Stop Mode. Not used. Leave open.

NMI# 117 I Ithpu Non-Maskable Interrupt. Not used. Connect to +3.3V.

RESET# 34 I It Reset. The active low RESET# input resets the SCM logic, and restores the

saved configuration from serial EEPROM or returns the modem to the

factory default values if NVRAM is not present.

RESET# low holds the modem in the reset state; RESET# going high

releases the modem from the reset state. After application of VDD, RESET#

must be held low for at least 15 ms after the VDD power reaches operating

range. The modem device set is ready to use 25 ms after the low-to-high

transition of RESET#.

For serial Interface, the RESET# input is typically connected to a reset

switch circuit.

VGG 60 P PWRG I/O Signaling Voltage Source. Connect to +3.3V.

VDD 2, 15, 20, 40,

53, 58, 78,

85, 100, 108,

116, 124

PPWRDigital Supply Voltage. Connect to VCC (+3.3V, filtered).

GND 10, 25, 30,

44, 48, 68,

90, 95, 103,

112, 120,

128

GGND Digital Ground. Connect to digital ground (GND).

SSD_RING# (PE6) 22 O It/Ot2 SmartDAA Raw Ring. A toggling edge used to indicate presence of a ring

frequency. The idle state (no ringing) output of the ring detect circuit is high.

SSD_INT (PA1) 26 O It/Ot2 SmartDAA Interface Interrupt. Active low output used to indicate to the host

when the SmartDAA Interface needs servicing.

SSD_RINGWAKE

(PA0)

24 O It/Ot2 SmartDAA Ring Wake. Active high output used to indicate to the host that a

valid ring or line polarity reversal has been detected.

PLLVDD 82 P PWR PLL Circuit Digital Supply Voltage. Connect to +3.3V and to GND through

1 µF.

PLLGND 83 G GND PLL Circuit Digital Ground. Connect to GND.

Serial EEPROM (NVRAM) Interface

NVMCLK (PA7) 33 O It/Ot2 NVRAM Clock. NVMCLK output high enables the EEPROM. Connect to

EEPROM SCL pin.

NVMDATA (PE3) 18 I/O It/Ot2 NVRAM Data. The NVMDATA pin supplies a serial data interface to the

EEPROM. Connect to EEPROM SDA pin and to +3.3V through 10 KΩ..

SmartSCM Modem Data Sheet

3-16 Conexant 100490C

Table 3-4. CX88168 SCM Pin Signal Definitions for Serial Interface (PARIF = Low)

Label Pin I/O I/O Type Signal Name/Description

Speaker Interface

DSPKOUT 98 O It/Ot2 Modem Speaker Digital Output. The DSPKOUT digital output reflects the

received analog input signal digitized to TTL high or low level by an internal

comparator.

DIB Interface

PWRCLKP 96 O Odpc Clock and Power Positive. Provides clock and power to the LSD. Connect

to DIB transformer primary winding non-dotted terminal.

PWRCLKN 97 O Odpc Clock and Power Negative. Provides clock and power to the LSD. Connect

to DIB transformer primary winding dotted terminal.

DIB_DATAP 93 I/O Idd/Odd Data Positive. Transfers data, control, and status information between the

SCM and the LSD. Connect to LSD through DIB data positive channel

components.

DIB_DATAN 94 I/0 Idd/Odd Data Negative. Transfers data, control, and status information between the

SCM and the LSD. Connect to LSD through DIB data negative channel

components.

External Bus Interface

A0-A9,

A10-A15,

A16 (PB0),

A17 (PB4),

A18 (PB5)

71-77, 79-81,

84, 86-89, 91,

99,

105,

106

It/Ot8,

It/Ot2,

It/Ot2

Address Lines 0-18. A0-A18 are the address output lines used to access

optional external memory; up to 4 Mbits (512k bytes) ROM/flash ROM using

A0-A18 and up to 1 Mbit (128k bytes) RAM using A0-A16.

If internal ROM is used for the base modem ROM code and external

ROM/flash ROM is used only for the additional GSM ROM code, the 128k-

byte GSM ROM code is located in the upper-most portion of the 512k-byte

address range with A17 used as GSM ROM select.

If external ROM/flash ROM is used for the base modem ROM, the 256k-byte

base modem ROM code is located in the 0-256k-byte address range. If

included, the 128k-byte GSM ROM code is located in the upper-most portion

of the 512k-byte address range.

D0-D7 62-67, 69-70 I/O Ith/Ot2 Data Line 0-7. D0-D7 are bidirectional external memory bus data lines.

READ# 119 O It/Ot2 Read Enable. READ# output low enables data transfer from the selected

device to the D0-D7 lines.

WRITE# 118 O It/Ot2 Write Enable. WRITE# output low enables data transfer from the D0-D7

lines to the selected device.

ROMSEL# (PB2) 102 O Ot2 ROM Select. ROMSEL# (PB2, ES3) output low selects the external

ROM/flash ROM.

RAMSEL# (PB3) 104 O It/Ot2 RAM Select. RAMSEL#, PB3 (ES2) output low selects the external RAM.

RESERVED (PB1) 101 O It/Ot2 Reserved. PB1 (ES4) is used internally. Leave open.

EXT_RES# (PB6) 107 O It/Ot2 External Device Reset. Active low reset for external devices. Leave open if

not used.

CX20437 VC Interface

IASLEEP (P_PF05) 50 O Ot2 Modem Sleep. Connect to VC SLEEP pin.

M_CLK (P_PB00) 37 O It/Ot2 Master Clock Output. Connect to VC M_CLKIN pin.

SR2CLK (P_PGP05) 92 I Itpu/Ot2 Voice Serial Clock input. Connect to VC M_SCK pin.

SA2CLK (P_PX05) 38 I Itpu/Ot2 Voice Serial Frame Sync Input. Connect to VC M_STROBE pin.

SR3OUT 35 O Ot2 Voice Serial Transmit Data Output. Connect to VC M_TXSIN pin.

SR3IN (P_PX01) 36 I Itk/Ot2 Voice Serial Receive Data Input. Connect to VC M_RXOUT pin.

SR2IO (P_PX06) 39 O It/Ot2 Voice Control Output. Connect to VC M_CNTRLSIN pin.

SmartSCM Modem Data Sheet

100490C Conexant 3-17

Table 3-4. CX88168 SCM Pin Signal Definitions for Serial Interface (PARIF = Low)

Label Pin I/O I/O Type Signal Name/Description

V.24 (EIA/TIA-232-E) DTE Serial Interface

These signals correspond functionally to V.24/EIA/TIA-232-E signals but are logically inverted.

TXD# (PA2) 27 I It/Ot2 Transmitted Data (EIA BA/ITU-T CT103). The DTE uses the TXD# line to

send data to the modem for transmission over the telephone line or to

transmit commands to the modem.

RXD# (PA6) 32 O It/Ot2 Received Data (EIA BB/ITU-T CT104). The modem uses the RXD# line to

send data received from the telephone line to the DTE and to send modem

responses to the DTE. During command mode, RXD# data represents the

modem responses to the DTE.

CTS# (PC1) 123 O Ith/Ot8 Clear To Send (EIA CB/ITU-T CT106). CTS# output ON (low) indicates

that the modem is ready to accept data from the DTE. In asynchronous

operation, in error correction or normal mode, CTS# is always ON (low)

unless RTS/CTS flow control is selected by the &Kn command.

In synchronous operation, the modem also holds CTS# ON during

asynchronous command state. The modem turns CTS# OFF immediately

upon going off-hook and holds CTS# OFF until both DSR# and RLSD# are

ON and the modem is ready to transmit and receive synchronous data. The

modem can also be commanded by the &Rn command to turn CTS# ON in

response to an RTS# OFF-to-ON transition.

DSR# (PC0) 122 O Ith/Ot8 Data Set Ready (EIA CC/ITU-T CT107). DSR# indicates modem status to

the DTE. DSR# OFF (high) indicates that the DTE is to disregard all signals

appearing on the interchange circuits except Ring Indicator (RI#). DSR#

output is controlled by the AT&Sn command.

RLSD# (PC2) 125 O Ith/Ot8 Received Line Signal Detector (EIA CF/ITU-T CT109). When AT&C0

command is not in effect, RLSD# output is ON when a carrier is detected

on the telephone line or OFF when carrier is not detected.

TM# (PC6) 3 O Ith/Ot8 Test Mode (EIA TM/ITU-T CT142). The TM# output indicates the modem is

in test mode (low) or in any other mode (high).

RI# (PC5) 1 O Ith/Ot8 Ring Indicator (EIA CE/ITU-T CT125). RI# output ON (low) indicates the

presence of an ON segment of a ring signal on the telephone line.

DTR# (PD4) 11 I It Data Terminal Ready (EIA CD/ITU-T CT108). The DTR# input is turned

ON (low) by the DTE when the DTE is ready to transmit or receive data.

DTR# ON prepares the modem to be connected to the telephone line, and

maintains the connection established by the DTE (manual answering) or

internally (automatic answering). DTR# OFF places the modem in the

disconnect state under control of the &Dn and &Qn commands.

RTS# (PD6) 13 I Ithpu Request To Send (EIA CA/ITU-T CT105). RTS# input ON (low) indicates

that the DTE is ready to send data to the modem. In the command state,

the modem ignores RTS#.

In asynchronous operation, the modem ignores RTS# unless RTS/CTS

flow control is selected by the &Kn command. In synchronous on-line

operation, the modem can be commanded by the &Rn command to ignore

RTS# or to respond to RTS# by turning on CTS# after the delay specified

by Register S26.

SmartSCM Modem Data Sheet

3-18 Conexant 100490C

Table 3-4. CX88168 SCM Pin Signal Definitions for Serial Interface (PARIF = Low)

Label Pin I/O I/O Type Signal Name/Description

LED Indicator Interface

AAIND# (PC4) 127 O Ith/Ot8 Auto Answer Indicator. AAIND# output ON (low) corresponds to the

indicator on. AAIND# output is active when the modem is configured to

answer the ring automatically (ATS0 command ≠ 0).

TMIND# (PB7) 109 O It/Ot8 Test Mode Indicator. TMIND# output ON (low) corresponds to the

indicator on. TMIND# output pulses (indicator flashes) when the modem is

in test mode and if an error is detected.

DTRIND# (PD0) 6 O Ithpd/Ot2 DTR Indicator. DTRIND# output ON (low) corresponds to the indicator on.

The DTRIND# state reflects the DTR# output state except when the &D0

command is active, in which case DTRIND# is low.

OHIND#/RXPAD#

(PE0)

14 O It/Ot8 Cellular RX Bias. In Line Mode (LINE/CELL = high), OHIND#/RXPAD#

(PE0) indicates the status of the off-hook relay. In Cell Mode (LINE/CELL =

low), this signal is defined by the cellular firmware driver.

Telephone Line/Analog Cellular Phone Interface Select

LINE/GSM (PA5) 31 I It/Ot2 Line/GSM Interface Select. Not used. Leave open.

LINE/CELL (PE7) 23 I It/Ot8 Line/Cellar Interface Select. Selects telephone line or cellular phone

(AMPS) interface, as follows:

LINE/CELL Interface Selected

H Telephone Line

L Cellular (AMPS)

The following ports operate as indicated for the selected interface:

Port* Telephone Line Analog Cellular

PE0 OHIND# RXPAD#

PE1 — TXPAD#

PE2 — CELBSY

PE5 — CELDATA

PA2 — —

PA3 — CELBSY#

PA4 — CELCLK

PA6 — GSMTXD

* Ports marked “—“ are not used.

Analog Cellular Phone Interface (LINE/CELL = Low)

CELCLK/GSMINP0

(PA4)

29 I Itpu/Ot2 Cellular Clock. Defined by the cellular firmware driver.

CELDATA (PE5) 21 I/O It/Ot2 Cellular Data. Defined by the cellular firmware driver.

CELBSY (PE2) 17 O It/Ot2 Cellular Busy. Defined by the cellular firmware driver.

CELBSY# (PA3) 28 I Itpu/Ot2 Cellular Not Busy. Defined by the cellular firmware driver.

OHIND#/RXPAD#

(PE0)

14 O It/Ot8 Cellular RX Bias. In Line Mode (LINE/CELL = high), OHIND#/RXPAD#

(PE0) indicates the status of the off-hook relay. In Cell Mode (LINE/CELL =

low), this signal is defined by the cellular firmware driver.

VOICE#/TXPAD#

(PE1)

16 O It/Ot2 Cellular TX Bias. Defined by the cellular firmware driver.

Telephone Interface (LINE/CELL = High and LINE/GSM = High)

VOICE#/TXPAD# (PE1) 16 O It/Ot2 Voice Relay Control. When the LINE/CELL input is high, this output

(typically active low) used to control the normally open voice relay. See

cellular interface signals for TXPAD# usage.

HS_LCS (PE4) 19 I It/Ot2 Handset Line Current Sense. LCS is an active high input that indicates a

handset off-hook status. Not required for data/fax/voice/speakerphone

operation. If not used, connect to GND through 47 KΩ.

SmartSCM Modem Data Sheet

100490C Conexant 3-19

Table 3-4. CX88168 SCM Pin Signal Definitions for Serial Interface (PARIF = Low)

Label Pin I/O I/O Type Signal Name/Description

Not Used

RESERVED (PC7) 4 I Ith/Ot8 Reserved. Connect to +3.3V through 47 KΩ.

RESERVED (PD5) 12 I Ithpu Reserved. Leave open.

NOXYCK 47 I Itpu Disable XCLK Output. When low, disables XCLK output (reduces internal

power consumption). When high, enables XCLK output. Connect to GND.

TESTP 110 I Itpu Test. Used for factory test only. Leave open.

DV1TP 111 I Itpu Test. Used for factory test only. Leave open.

XCLK 49 O It/Ot2 Not Used. Leave open.

S4RIN 45 I Itk Not Used. Leave open.

PHS2 121 O Ot2 Not Used. Leave open.

PC3 126 I/O Ith/Ot8 Not Used. Leave open.

PD1 7 I/O Ithpd/Ot2 Not Used. Leave open.

PD2 8 I/O Ithpd/Ot2 Not Used. Leave open.

PD7 46 I/O It/Ot2 Not Used. Leave open.

P_PX00 41 I/O It/Ot8 Not Used. Leave open.

P_PX02 42 I/O Itpu/Ot2 Not Used. Leave open.

P_PX03 43 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (GP00) 52 I/O It/Ot2 Not Used. Leave open.

RESERVED (P_PA00) 55 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (P_PA01) 57 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (P_PA04) 54 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED (P_PA05) 56 I/O Itk/Ot2 Not Used. Leave open.

RESERVED (P_PB01) 51 I/O Itpu/Ot2 Not Used. Leave open.

RESERVED

(P_BD2CLK)

59 I/O Itpu/Ot2 Not Used. Leave open.

Notes:

1. I/O Types: See Table 3-5.

2. Interface Legend:

DIB Digital Isolation Barrier

EB Expansion Bus

HB Host Bus

NC No internal pin connection

VC Voice Codec

RESERVED = No external connection allowed (may have internal connection).

SmartSCM Modem Data Sheet

3-20 Conexant 100490C

Table 3-5. CX88168 SCM I/O Type Definitions

I/O Type Description

Idd/Odd Digital input/output, DIB data transceiver

Ix/Ox I/O, wire

It/Ot2 Digital input, +5V tolerant/ Digital output, 2 mA, ZINT = 120 Ω

Itk/Ot2 Digital input, +5V tolerant, keeper/ Digital output, 2 mA, ZINT = 120 Ω

Itpu/Ot2 Digital input, +5V tolerant, 75k Ω pull up/ Digital output, 2 mA, ZINT = 120 Ω

It/Ot8 Digital input, +5V tolerant,/ Digital output, 8 mA, ZINT = 50 Ω

Ithpd/Ot2 Digital input, +5V tolerant, hysteresis, 75k Ω pull down/ Digital output, 2 mA, ZINT = 120 Ω

Ith/Ot2 Digital input, +5V tolerant, hysteresis/Digital output, 2 mA, ZINT = 120 Ω

Ith/Ot8 Digital input, +5V tolerant, hysteresis/Digital output, 8 mA, ZINT = 50 Ω

It Digital input, +5V tolerant

Itk Digital input, +5V tolerant, keeper

Itkpu Digital input, +5V tolerant, keeper, 75k Ω pull up

Itpu Digital input, +5V tolerant, 75k Ω pull up

Ithpu Digital input, +5V tolerant, hysteresis, 75k Ω pull up

Odpc Digital output with adjustable drive, DIB clock and power

Ot2 Digital output, three-state, 2 mA, ZINT = 120 Ω

PWR VCC Power

PWRG VGG Power

GND Ground

NOTES:

1. See DC characteristics in Table 3-6.

2. I/O Type corresponds to the device Pad Type. The I/O column in signal interface tables refers to signal I/O direction used in the

application.

Table 3-6. CX88168 SCM DC Electrical Characteristics

Parameter Symbol Min. Typ. Max. Units Test Conditions

Input Voltage Low VIL

+5V tolerant 0 – 0.8 V

+5V tolerant hysteresis 0 – 0.3 *VGG V

Input Voltage High VIH – V

+5V tolerant 2 – 5.25 V

+5V tolerant hysteresis 0.7 * VDD – 5.25 V

Input Hysteresis VH – V

+3V hysteresis 0.5 – V

+5V tolerant, hysteresis 0.3 – V

Output Voltage Low VOL

ZINT = 120 Ω0 – 0.4 V IOL = 2 mA

ZINT = 50 Ω0 – 0.4 V IOL = 8 mA

Output Voltage High VOH – V

ZINT = 120 Ω2.4 – VDD V IOL = -2 mA

ZINT = 50 Ω2.4 – VDD V IOL = -8 mA

Pull-Up Resistance Rpu 50 – 200 kΩ

Pull-Down Resistance Rpd 50 – 200 kΩ

Test conditions unless otherwise noted:

1. Test Conditions unless otherwise stated: VDD = +3.3 ± 0.3 VDC; TA = 0°C to 70°C; external load = 50 pF.

SmartSCM Modem Data Sheet

100490C Conexant 3-21

3.2 CX20463 SmartDAA LSD Hardware Pins and Signals

3.2.1 General

3.2.2 SCM Interface (Through DIB)

The DIB interface signals are:

• Clock (CLK); input

• Digital Power (PWR+); input power

• Digital Ground (DGND); digital ground

• Data Positive (DIB_P); input

• Data Negative (DIB_N); input

3.2.3 Telephone Line Interface

The telephone line interface signals are:

• RING AC Coupled (RAC1); input

• TIP AC Coupled (TAC1); input

• Electronic Inductor Resistor (EIR); output

• TIP and RING DC Measurement (TRDC); input

• DAC Output Voltage (DAC); output

• Electronic Inductor Capacitor (EIC)

• Electronic Inductor Output (EIO)

• Electronic Inductor Feedback (EIF)

• Resistive Divider Midpoint (DCF)

• Transmit Analog Output (TXA); output

• Receive Analog Input (RXI); input

• Receiver Gain (RXG); output

• MOV Enable (MOVEN); output

• Worldwide Impedance 0 (ZW0); input

• US Impedance 0 (ZUS0); input

• Transmit Feedback (TXF); input

• Transmit Output (TXO); output

3.2.4 CX20463 LSD Pin Assignments and Signal Definitions

LSD 32-pin TQFP hardware interface signals are shown by major interface in Figure 3-5, are shown by pin number in Figure

3-6, and are listed by pin number in Table 3-7.

LSD pin signals are defined in Table 3-8.

LSD pin signal digital electrical characteristics are defined in Table 3-9.

SmartSCM Modem Data Sheet

3-22 Conexant 100490C

RAC2

TAC2

RAC1

TAC1

EIR

EIC

DAC

TRDC

EIO

EIF

RXI

RXG

TXA

MOVEN (GPIO1)

ZW0

ZUS0

TXO

TXF

DCF

VREF

RBIAS

GPIO2

100491_F3-09_HI CX20463

CX20463

SMARTDAA

LINE SIDE

DEVICE

(LSD)

32-PIN TQFP

Electronic

Inductor,

Off-Hook,

Pulse Dial,

and TIP and

RING VI

Control

AGND_LSD

Safety

and EMI

Protection

AGND_LSD

Ring

Filter

AGND_LSD

C42

C44

C45

AGND_LSD

Echo

Cancellation

and

Receiver

Impedance

Matching

and

Transmitter

Pulse Dial

Voltage

Protection

(Country

Specific)

R54

AGND_LSD

CLK

PWR+

AVDD

DVDD

DGND

AGND

DIB_P

DIB_N

POR

GND_LSD

C30 C28

R34

R36

AGND_LSD

DIGITAL

ISOLATION

BARRIER

(DIB)

PWRCLKN

PWRCLKP

DIB_DATAP

DIB_DATAN

DATA

CHANNEL

POWER AND

CLOCK

CHANNEL

R120

C70

C22

C24

Telephone

Line

Connector

TIP

RING

C26

R32

DVDD

R125

R124R110

C112

C110

R112

NOTES:

1. Consult applicable reference design for exact

component placement and values.

2. R125 is usually installed.

3. R124 is usually removed.

C72C62

C74

C76

Figure 3-5. CX20463 LSD Hardware Interface Signals

100491F3-7 PO-20463-32T

GPIO2

EIC

RXI

RXG

TRDC

DAC

VREF

AVDD

AGND

EIF

EIO

TXO

TXF

TXA

ZUS0

RAC1

RAC2

TAC1

TAC2

RBIAS

ZW0

EIR

DCF

MOVEN (GPIO1)

PWR+

POR

DIB_N

DIB_P

CLK

DVDD

DGND

CX20463

Figure 3-6. CX20463 LSD 32-Pin TQFP Pin Signals

SmartSCM Modem Data Sheet

100490C Conexant 3-23

Table 3-7. CX20463 LSD 32-Pin TQFP Pin Signals

Pin Signal Label I/O Type Interface

1 GPIO2 It/Ot12 NC

2 EIC Oa Telephone Line Interface Components

3 RXI Ia Telephone Line Interface Components

4 RXG Oa Telephone Line Interface Components

5 TRDC Oa Telephone Line Interface Components

6 DAC Oa Telephone Line Interface Components

7 VC REF VREF through C42 and to AGND_LSD through C44 and C74

8 VREF REF VC through C42 and to AGND_LSD through C45 and C76

9 RAC1 Ia Diode bridge top AC connection (RING) through R2 and C2

10 RAC2 Ia NC

11 TAC1 Ia Diode bridge bottom AC connection (TIP) through R4 and C4

12 TAC2 Ia NC

13 RBIAS Ia AGND_LSD through R54

14 ZW0 Ia Telephone Line Interface Components

15 EIR Ot12 Telephone Line Interface Components

16 DCF Ia AGND_LSD

17 ZUS0 Ia Telephone Line Interface Components

18 TXA Oa Telephone Line Interface Components

19 TXF Ia Telephone Line Interface Components

20 TXO Oa Telephone Line Interface Components

21 EIO Oa Telephone Line Interface Components

22 EIF Ia Telephone Line Interface Components

23 AGND AGND_LSD AGND_LSD

24 AVDD PWR LSD DVDD pin

25 DGND GND_LSD DIB transformer secondary winding undotted terminal through diode D2 and R120 in series

and to GND_LSD

26 DVDD PWR LSD AVDD pin, to GND_LSD through C28, C30, and C72 in parallel, and to DIB

transformer secondary winding dotted terminal through R124.

27 CLK I DIB transformer secondary winding undotted terminal through C26 and R32 in series, and

through R120 shared with LSD DGND pin through diode D2

28 DIB_P I/O DIB C22 through R34

29 DIB_N I/O DIB C24 through R36

30 POR It LSD DVDD pin

31 PWR+ PWR DIB transformer secondary winding dotted terminal through R125 and to GND_LSD

through zener diode D4 and C70 in parallel

32 MOVEN (GPIO1) Ot12 Telephone Line Interface Components

Notes:

1. I/O types:

Ia Analog input

It Digital input, TTL-compatible, (See Table 3-9)

Oa Analog output

Ot12 Digital output, TTL-compatible, 12 mA, ZINTERNAL = 32 Ω (See Table 3-9)

AGND_LSD Isolated LSD Analog Ground

GND_LSD Isolated LSD Digital Ground

2. Interface components may vary (see reference design for exact components and values).

SmartSCM Modem Data Sheet

3-24 Conexant 100490C

Table 3-8. CX20463 LSD Pin Signal Definitions

Label Pin I/O Type Signal Name/Description

SYSTEM SIGNALS

AVDD 24 PWR Analog Power Supply. Connect to the LSD DVDD pin.

AGND 23 AGND_LSD LSD Analog Ground. LSD Analog Ground. Connect to AGND_LSD at the

GND_LSD/AGND_LSD tie point and to the analog ground plane.

POR 30 It Power-On Reset. Connect to LSD DVDD pin.

VREF 8 REF Output Reference Voltage. Connect to VC through C42 and to AGND_LSD through

C45 and C76. Ensure a very close proximity between C42 and C45 and the VREF pin.

VC 7 REF Output Middle Reference Voltage. Connect to VREF through V42 and to AGND_LSD

through C44 and C74. Ensure a very close proximity between C44 and the VC pin. Use

a short path and a wide trace to AGND_LSD pin.

DIB INTERFACE SIGNALS

CLK 27 I Clock. Provides input clock, AC-coupled, to the LSD. Connect to DIB transformer

secondary winding undotted terminal through R32 and C26 in series, and through R120

shared with LSD DGND pin through diode D2.

PWR+ 31 PWR Digital Power Input. Provides unregulated input digital power to the LSD. Connect to

DIB transformer secondary winding dotted terminal through R125, and to GND_LSD

though zener diode D4 and C70 in parallel.

DVDD 26 PWR Digital Power. Connect to pin 24 (AVDD), to DIB transformer secondary winding

dotted terminal through R124, and to GND_LSD through C28, C30, and C72 in parallel.

DGND 25 GND_LSD LSD Digital Ground. Connect to DIB transformer secondary winding undotted terminal

through diode D2 in series with R120, and to GND_LSD at the GND_LSD/AGND_LSD

tie point.

DIB_P 28 I/O Data and Control Positive. Connect to HSD DIB_DATAP through C22 in the DIB and

R34 on the LSD side. DIB_P and DIB_N signals are differential, and ping-pong between

DIB and HSD (half duplex).

DIB_N 29 I/O Data and Control Negative. Connect to HSD DIB_DATAN through C24 in the DIB and

R36 on LSD side. DIB_P and DIB_N signals are differential, and ping-pong between

DIB and HSD (half duplex).

TIP AND RING INTERFACE

RAC1,

TAC1

Ia,

RING1 AC Coupled and TIP1 AC Coupled. AC-coupled voltage from telephone line

used to detect ring.

Connect RAC1 to the diode bridge AC top connection (RING) through R2 and C2.

Connect TAC1 to the diode bridge AC bottom connection (TIP) through R4 and C4.

RAC2

TAC2

10,

Ia,

RING2 AC Coupled and TIP2 AC Coupled. Not used. Leave open.

EIR 15 Oa Electronic Inductor Resistor. Electronic inductor resistor switch.

EIC 2 Oa Electronic Inductor Capacitor Switch. Internally switched to no connect when pulse

dialing and to ground all other times. This is needed to eliminate pulse dial interference

from the electronic inductor AC filter capacitor.

DAC 6 Oa DAC Output Voltage. Output voltage of the reference DAC.

TRDC 5 Ia TIP and RING DC Measurement. Input on-hook voltage (from a resistive divider).

Used internally to extract TIP and RING DC voltage and Line Polarity Reversal (LPR)

information.

EIO 21 Oa Electronic Inductor Output. Calculated voltage is applied to this output to control

offhook, pulse dial, and DC IV mask operation.

EIF 22 Ia Electronic Inductor Feedback. Electronic inductor feedback.

RXG 4 Oa Receiver Gain. Receiver operational amplifier output.

RXI 3 Ia Receive Analog Input. Receiver operational amplifier inverting input.

TXA 18 Oa Transmit Analog Output. Transmit signal used for canceling echo in the receive path.

SmartSCM Modem Data Sheet

100490C Conexant 3-25

Table 3-8. CX20463 LSD Pin Signal Definitions (Continued)

Label Pin I/O Type Signal Name/Description

TELEPHONE LINE INTERFACE (CONTINUED)

MOVEN (GPIO1) 32 Ot12 MOV Enable. Connect to pulse dial voltage protection circuit for Australia/Poland/Italy

use. Leave open if the product is not intended for Australia, Poland, or Italy.

RBIAS 13 Ia Receiver Bias. Connect to GND through R54.

DCF 16 Ia Resistive Divider Midpoint. Connect to LSD analog ground.

ZW0 14 Ia Worldwide Impedance 0. Input signal used to provide line complex impedance

matching for worldwide countries.

ZUS0 17 Ia US Impedance 0. Input signal used to provide line impedance matching for U.S.

TXO 20 Oa Transmit Output. Outputs transmit signal and impedance matching signal; connect to

transmitter transistor (Q6).

TXF 19 Ia Transmit Feedback. Connect to emitter of transmitter transistor (Q6).

NOT USED

GPIO2 1 It/Ot12 General Purpose I/O 2. Leave open if not used.

Notes:

1. I/O types:

Ia Analog input

It Digital input, TTL-compatible (See Table 3-9)

Oa Analog output

Ot12 Digital output, TTL-compatible, 12 mA, ZINTERNAL = 32 Ω (See Table 3-9)

AGND_LSD Isolated LSD Analog Ground

GND_LSD Isolated LSD Digital Ground

2. Interface components may vary (see reference design for exact components and values).

Table 3-9. CX20463 LSD DC Electrical Characteristics

Parameter Symbol Min. Typ. Max. Units Test Conditions

Input Voltage Low VIN -0.30 – 3.60 V VDD = +3.6V

Input Voltage Low VIL ––1.0V

Input Voltage High VIH 1.6 – – V

Output Voltage Low VOL 0 – 0.33 V

Output Voltage High VOH 2.97 – – V

Input Leakage Current – -10 – 10 µA

Output Leakage Current (High Impedance) – -10 – 10 µA

GPIO Output Sink Current at 0.4 V maximum – 2.4 – - mA

GPIO Output Source Current at 2.97 V minimum – 2.4 – - mA

GPIO Rise Time/Fall Time 20 100 ns

Test conditions unless otherwise noted:

1. Test Conditions unless otherwise stated: VDD = +3.3 ± 0.3 VDC; TA = 0°C to 70°C; external load = 50 pF

SmartSCM Modem Data Sheet

3-26 Conexant 100490C

3.3 CX20437 VC Hardware Pins and Signals (S Models)

3.3.1 General

Microphone and analog speaker interface signals, as well as telephone handset/headset interface signals are provided to

support functions such as speakerphone mode, telephone emulation, microphone voice record, speaker voice playback, and

call progress monitor.

Cellular analog transmit and receive interface signals are provided for direct connection to an analog cell phone.

Speakerphone Interface

The following signals are supported:

• Speaker Out (M_SPKR_OUT); analog output - Should be used in speakerphone designs where sound quality is important

• Microphone (M_MIC_IN); analog input

Telephone Handset/Headset Interface (In Lieu of Analog Cellular Connection)

The following interface signals are supported:

• Telephone Input (M_LINE_IN), input (TELIN) - Optional connection to a telephone handset interface circuit

• Telephone output (M_LINE_OUTP); output (TELOUT) - Optional connection to a telephone handset interface circuit

• Center Voltage (VC); output reference voltage

Analog Cellular Phone Interface (In Lieu of Telephone Handset/Headset Connection)

The following interface signals are supported:

• Cellular Analog Transmit (CEL_TX), output - Optional connection to an analog cell phone

• Cellular Analog Receive (CEL_RX), input - Optional connection to an analog cell phone

SCM Interface

The following interface signals are supported:

• Sleep (SLEEP); input

• Master Clock (M_CLKIN); input

• Serial Clock (M_SCK); output

• Control (M_CNTRLSIN); input

• Serial Frame Sync (M_STROBE); output

• Serial Transmit Data (M_TXSIN); input

• Serial Receive Data (M_RXOUT); output

Host Interface

The following interface signals are supported:

• Reset (POR); input

3.3.2 CX20437 VC Pin Assignments and Signal Definitions

VC 32-pin TQFP hardware interface signals are shown by major interface in Figure 3-7, are shown by pin number in Figure

3-8, and are listed by pin number in Table 3-10.

VC hardware interface signals are defined in Table 3-11.

VC pin signal DC electrical characteristics are defined in Table 3-12.

VC pin signal analog electrical characteristics are defined in Table 3-13.

SmartSCM Modem Data Sheet

100490C Conexant 3-27

100491_F3-7_HI_20437 32T

CX20437

VOICE CODEC

(VC)

32-PIN TQFP

AUDIO

CIRCUIT

SPKOUT

MIC

TELIN

TELOUT

CEL_RX

CEL_TX

CX88168

SCM

+3.3V

VAA (+3.3V)

IASLEEP

DRESET#

M_CLK

V_SCLK

V_STROBE

V_TXSIN

V_RXOUT

V_CTRL

SLEEP

POR

M_CLKIN

M_SCK

M_STROBE

M_TXSIN

M_RXOUT

M_CNTRLSIN

VDD

MAVDD

VSS

SET3V_BAR2

MAVSS

VSUB

M_DIG_SPEAKER

M_MIC_IN

M_SPKR_OUT

M_LINE_IN

M_LINE_OUTP

M_LINE_OUTM

VREF

M_MIC_BIAS

M_RELAYA

M_RELAYB

M_ACT90

M_1BIT_OUT

D_LPBK_BAR

0.1

AGND

0.1 10

HANDSET

INTERFACE

AGND

GND

FERRITE

VC_HAND

ANALOG

CELL PHONE

Figure 3-7. CX20437 VC Hardware Interface Signals

100491 F3-8 PO-CX20437

SLEEP

M_DIG_SPEAKER

M_SPKR_OUT

POR

MAVDD

MAVSS

M_RELAYA

M_STROBE

M_RXOUT

M_SCK

M_TXSIN

M_CLKIN

M_CNTRLSIN

VDD

M_LINE_OUTP

M_LINE_OUTM

VREF

M_MIC_IN

M_LINE_IN

M_MIC_BIAS

M_RELAYB

D_LPBK_BAR

M_1BIT_OUT

M_ACT90

VSS

VSUB

SET3V_BAR2

VDD

CX20437

Figure 3-8. CX20437 VC 32-Pin TQFP Pin Signals

SmartSCM Modem Data Sheet

3-28 Conexant 100490C

Table 3-10. CX20437 VC 32-Pin TQFP Pin Signals

Pin Signal Label I/O I/O Type Interface

1 SLEEP I Itpd SCM: IASLEEP

2 M_DIG_SPEAKER O Ot2 NC

3 M_SPKR_OUT O Oa Speaker interface circuit

4 POR I Itpu Host: RESET# or reset circuit

5 MAVDD PWR VAA (+3.3V)

6 MAVSS AGND AGND

7NC NC

8NC NC

9 M_LINE_OUTP O Oa Handset interface circuit: TELOUT; or Cell Phone: CEL_TX

10 M_LINE_OUTM O Oa NC

11 VREF REF VC through capacitors

12 VC REF AGND through ferrite bead and capacitors. For handset interface, connect also

to VC_HAND through ferrite bead

13 M_MIC_IN I Ia Microphone interface circuit

14 M_LINE_IN I Ia Handset interface circuit: TELIN; or Cell Phone: CEL_RX

15 M_MIC_BIAS NC

16 M_RELAYB NC

17 VDD PWR +3.3V

18 M_CNTRLSIN I Itpd SCM: V_CTRL

19 M_CLKIN I Itpd SCM: M_CLK

20 M_TXSIN I Itpd SCM: V_TXSIN

21 M_SCK O Ot2 SCM: V_SCLK

22 M_RXOUT O Ot2 SCM: V_RXOUT

23 M_STROBE O Ot2 SCM: V_STROBE

24 M_RELAYA O Ot2od NC

25 VDD PWR +3.3V

26 M_SET3V_BAR2 I Itpu GND

27 VSUB AGND AGND

28 VSS GND GND

29 M_ACT90 I Itpu NC

30 M_1BIT_OUT O Ot2 NC

31 D_LPBK_BAR I Itpu NC

32 NC NC

Notes:

1. I/O types:

Ia Analog input

It Digital input, TTL-compatible

Itpd Digital input, TTL-compatible, internal 75k ± 25k Ω pull-down

Itpu Digital input, TTL-compatible, internal 75k ± 25k Ω pull-up

Oa Analog output

Ot2 Digital output, TTL-compatible, 2 mA, ZINTERNAL = 120 Ω

Ot2od Digital output, TTL-compatible, 2 mA, open drain, ZINTERNAL = 120 Ω

AGND Analog Ground

GND Digital Ground

*See CX20437 VC DC Electrical Characteristics (Table 3-12) and CX20437 VC Analog Electrical Characteristics Table 3-13.

SmartSCM Modem Data Sheet

100490C Conexant 3-29

Table 3-11. CX20437 VC Pin Signal Definitions

Label Pin I/O Type Signal Name/Description

SYSTEM SIGNALS

VDD 17, 25 PWR Digital Power Supply. Connect to +3.3V and digital circuits power supply filter.

MAVDD 5 PWR Analog Power Supply. Connect to +3.3V and analog circuits power supply filter.

VSS 28 GND Digital Ground. Connect to GND.

MAVSS 6 AGND Analog Ground. Connect to AGND.

VSUB 27 GND Analog Ground. Connect to AGND.

POR 4 Itpu Power-On Reset. Active low reset input. Connect to Host RESET# or reset circuit.

SET3V_BAR2 26 Itpu Set +3.3V Analog Reference. Connect to GND.

SCM INTERCONNECT

SLEEP 1 Itpd IA Sleep. Active high sleep input. Connect to SCM IASLEEP pin.

M_CLKIN 19 Itpd Master Clock Input. Connect to SCM M_CLK pin.

M_SCK 21 Ot2 Serial Clock Output. Connect to SCM V_SCLK pin.

M_CNTRL_SIN 18 Itpd Control Input. Connect to SCM V_CTRL pin.

M_STROBE 23 Ot2 Serial Frame Sync. Connect to SCM V_STROBE pin.

M_TXSIN 20 Itpd Serial Transmit Data. Connect to SCM V_TXSIN pin.

M_RXOUT 22 Ot2 Serial Receive Data. Connect to SCM V_RXOUT pin.

MICROPHONE/SPEAKER INTERFACE

M_MIC_IN 13 I(DA) Microphone Input. Single-ended analog input from the microphone circuit.

M_SPKR_OUT 3 O(DF) Modem Speaker Analog Output. The M_SPKR_OUT analog output reflects the received

analog input signal. The M_SPKR_OUT on/off and three levels of attenuation are controlled

by bits in DSP RAM. When the speaker is turned off, the M_SPKR_OUT output is clamped

to the voltage at the VC pin. The M_SPKR_OUT output can drive an impedance as low as

300 ohms. In a typical application, the M_SPKR_OUT output is an input to an external

LM386 audio power amplifier.

HANDSET/HEADSET INTERFACE (IN LIEU OF CELL PHONE CONNECTION)

M_LINE_OUTP 9 O(DF) Telephone Handset Out (TELOUT). Single-ended analog data output to the telephone

handset circuit. The output can drive a 300 Ω load.

M_LINE_IN 14 I(DA) Telephone Handset Out (TELIN). Single-ended analog data input from the telephone

handset circuit.

CELL PHONE INTERFACE (IN LIEU OF HANDSET/HEADSET CONNECTION)

M_LINE_OUTP 9 O(DF) Cellular Transmit (CEL_TX). Single-ended analog transmit output. Connect to the analog

cell phone transmit input. The output can drive a 300 Ω load. Leave open if not used.

M_LINE_IN 14 I(DA) Cellular Receive (CEL_RX). Single-ended analog receive input. Connect to the analog cell

phone receive output. Connect to AGND if not used.

REFERENCE VOLTAGE

VREF 11 REF High Voltage Reference. Connect to VC through 10 µF (polarized, + terminal to VREF) and

0.1 µF (ceramic) in parallel. Ensure a very close proximity between these capacitors and

VREF pin.

VC 12 REF Low Voltage Reference. Connect to analog ground through ferrite bead in series with 10

µF (polarized, + terminal to VC) and 0.1 µF (ceramic) in parallel. Ensure a very close

proximity between these capacitors and VC pin. Use a short path and a wide trace to AGND

pin.

For handset interface, also connect to handset interface circuit (VC_HAND) through a ferrite

bead.

SmartSCM Modem Data Sheet

3-30 Conexant 100490C

Table 3-11. CX20437 VC Pin Signal Definitions (Continued)

Label Pin I/O Type Signal Name/Description

NOT USED

M_DIG_SPEAKER 2 Ot2 Not Used. Leave open.

M_LINE_OUTM 10 Oa Not Used. Leave open.

M_RELAYA 24 Ot Not Used. Leave open.

M_RELAYB 16 Ot Not Used. Leave open.

M_MIC_BIAS 15 Oa Not Used. Leave open.

M_ACT90 29 Itpu Not Used. Leave open.

M_1BIT_OUT 30 Ot2 Not Used. Leave open.

D_LPBK_BAR 31 It Not Used. Leave open.

NC 7, 8, 32 NC Internal No Connect. Leave open.

Notes:

1. I/O types*:

Ia Analog input

It Digital input, TTL-compatible

Itpd Digital input, TTL-compatible, internal 75k ± 25k Ω pull-down

Itpu Digital input, TTL-compatible, internal 75k ± 25k Ω pull-up

Oa Analog output

Ot2 Digital output, TTL-compatible, 2 mA, ZINTERNAL = 120 Ω

Ot2od Digital output, TTL-compatible, 2 mA, open drain, ZINTERNAL = 120 Ω

AGND Analog Ground

GND Digital Ground

SmartSCM Modem Data Sheet

100490C Conexant 3-31

Table 3-12. CX20437 VC DC Electrical Characteristics

Parameter Symbol Min. Typ. Max. Units Test Conditions

Input Voltage Low VIN -0.30 – VDD+0.3 V

Input Voltage Low VIL -0.30 – VDD+0.3 V

Input Voltage High VIH 0.4*VDD – – V

Output Voltage Low VOL 0–0.4V

Output Voltage High VOH 0.8*VDD – VDD V

Input Leakage Current – -10 – 10 µA

Output Leakage Current (High Impedance) – -10 – 10 µA

Test conditions unless otherwise noted:

1. Test Conditions unless otherwise stated: VDD = +3.3 ± 0.3 VDC; TA = 0°C to 70°C; external load = 50 pF

Table 3-13. CX20437 VC Analog Electrical Characteristics

Signal Name Type Characteristic Value

M_LINE_IN, I (DA) Input Impedance > 70K Ω

M_MIC_IN AC Input Voltage Range 1.1 VP-P

Reference Voltage +1.35 VDC

M_LINE_OUTP O (DD) Minimum Load 300 Ω

Maximum Capacitive Load 0 µF

Output Impedance 10 Ω

AC Output Voltage Range 1.4 VP-P (with reference to ground and a 600 Ω load)

Reference Voltage +1.35 VDC

DC Offset Voltage ± 200 mV

M_SPKR_OUT O (DF) Minimum Load 300 Ω

Maximum Capacitive Load 0.01 µF

Output Impedance 10 Ω

AC Output Voltage Range 1.4 VP-P

Reference Voltage +1.35 VDC

DC Offset Voltage ± 20 mV

Test conditions unless otherwise noted:

1. Test Conditions unless otherwise stated: VDD = +3.3 ± 0.3 VDC; MAVDD = +3.3 ± 0.3 VDC, TA = 0°C to 70°C

Parameter Min Typ Max Units

DAC to Line Driver output (600Ω load, 3dB in SCF and CTF) SNR/SDR at:

4Vp-p differential

2Vp-p differential

-10dBm differential

88/85

82/95

72/100

DAC to Speaker Driver output (150Ω load, 3dB in SCF and CTF, -6dB in speaker driver)

SNR/SDR at:

2Vp-p

1Vp-p

-10dBm

88/75

82/80

72/83

Line Input to ADC (6dB in AAF) SNR/SDR at –10 dBm 80/95 dB

Input Leakage Current (analog inputs) -10 10 µA

Output Leakage Current (analog outputs) -10 10 µA

SmartSCM Modem Data Sheet

3-32 Conexant 100490C

3.4 Electrical and Environmental Specifications

3.4.1 Operating Conditions, Absolute Maximum Ratings, and Power Requirements

The operating conditions are specified in Table 3-14.

The absolute maximum ratings are listed in Table 3-15.

The current and power requirements are listed in Table 3-16.

Table 3-14. Operating Conditions

Parameter Symbol Limits Units

Supply Voltage VDD +3.0 to +3.6 VDC

Operating Temperature Range TA0 to +70 °C

Table 3-15. Absolute Maximum Ratings

Parameter Symbol Limits Units

Supply Voltage VDD -0.5 to +4.0 VDC

Input Voltage VIN -0.5 to (VGG +0.5)* VDC

Storage Temperature Range TSTG -55 to +125 °C

Analog Inputs VIN -0.3 to (VAA + 0.5) VDC

Voltage Applied to Outputs in High Impedance (Off) State VHZ -0.5 to (VGG +0.5)* VDC

DC Input Clamp Current IIK ±20 mA

DC Output Clamp Current IOK ±20 mA

Static Discharge Voltage (25°C) VESD ±2500 VDC

Latch-up Current (25°C) ITRIG ±400 mA

* VGG = +3.3V ± 0.3V or +5V ± 5%.

Table 3-16. Current and Power Requirements

Mode

Typical

Current

(Ityp)

(mA)

Maximum

Current

(Imax)

(mA)

Typical

Power

(Ptyp)

(mW)

Maximum

Power

(Pmax)

(mW)

Notes

CX88168 SCM and CX20463 LSD

Normal Mode: Off-hook, normal data connection 142 156 470 562 f = 28.224 MHz

Normal Mode: On-hook, idle, waiting for ring 132 145 436 522 f = 28.224 MHz

Sleep Mode 42 46 140 166 f = 0 MHz

CX20437 VC (Optional)

Normal Mode 1.5 2 5 7

Notes:

1. Operating voltage: VDD = +3.3V ± 0.3V.

2. Test conditions: VDD = +3.3V for typical values; VDD = +3.6V for maximum values.

3. Input Ripple

≤ 0.1 Vpeak-peak.

4. f = Internal frequency.

5. Maximum current computed from Ityp: Imax = Ityp * 1.1.

6. Typical power (Ptyp) computed from Ityp: Ptyp = Ityp * 3.3V; Max power (Pmax) computed from Imax: Pmax = Imax * 3.6V.

SmartSCM Modem Data Sheet

100490C Conexant 3-33

3.4.2 Interface and Timing Waveforms

External Memory Bus Timing

The external memory bus timing is listed in Table 3-17 and illustrated in Figure 3-9.

Table 3-17. Timing - External Memory Bus

Symbol Parameter Min Typ. Max Units

tFI Internal Operating Frequency 28.224 MHz

tCYC Internal Operating Clock Cycle 35.43 ns

Read

tAS READ# High to Address Valid – 6.5 9 ns

tES READ# High to ES Valid – 8 11 ns

tRW READ# Pulse Width 17.72 – – ns

tRDS Read Data Valid to READ# High 6.1 – – ns

tRDH READ# High to Read Data Hold 0 0 – ns

Write

tAS WRITE# High to Address Valid – 6.5 8 ns

tES WRITE# High to ES Valid – 8 11 ns

tWW WRITE# to WRITE# Pulse Width 17.72 – 124 ns

tWTD WRITE# Low to Write Data Valid – 5 8.2 ns

tWTH WRITE# High to Write Data Hold 5.0 – – ns

Notes:

1. ES = RAMSEL# or ROMSEL#.

2. Read pulse width and write pulse width:

RAM: tRW, tWW = 0.5 tCYC = 17.72 ns for Non-Extended Cycle Timing

ROM: tRW, tWW = 3.5 tCYC = 124 ns for Extended Cycle Timing

3. Memory speed determination:

RAM: tACCESS = tCYC - tES - tRDS = 35.43 – 11 - 6.1 = 18.33 ns (i.e., use 15 ns memory)

ROM: tACCESS = 4(tCYC) - tES - tRDS = 4(35.43) – 11 - 6.1 = 124.62 ns (i.e., use 90 ns memory).

4. Output Enable to Output Delay Timing:

RAM: tOE = tRW - tRDS = 0.5(tCYC) - tRDS = 17.72 - 6.1 = 11.62 ns

ROM: tOE = tRW - tRDS = 3.5(tCYC) - tRDS = 124. - 6.1 = 117.90 ns.

SmartSCM Modem Data Sheet

3-34 Conexant 100490C

Write Timing

Read Timing

tCYC

tAS

RDH

C2*

A[18:0]

tRW

RDS

READ#

D[7:0]

ES#**

tES

* C2 = Internal Phase 2 clock.

** ES# = RAMSEL# or ROMSEL#.

100491 F3-09 WF EB

tCYC

tAS

tWW

ttWTH

WTD

C2*

A[18:0]

WRITE#

D[7:0]

ES#**

* C2 = Internal Phase 2 clock.

** ES# = RAMSEL# or ROMSEL#.

Figure 3-9. Waveforms - External Memory Bus

SmartSCM Modem Data Sheet

100490C Conexant 3-35

Parallel Host Bus Timing

The parallel host bus timing is listed in Table 3-18 and illustrated in Figure 3-10.

Table 3-18. Timing - Parallel Host Bus

Symbol Parameter Min Max Units

READ (See Notes 1, 2, 3, 4, 5, and 6)

tAS Address Setup 5 – ns

tAH Address Hold 10 – ns

tCS Chip Select Setup 0 – ns

tCH Chip Select Hold 10 – ns

tRD HRD# Strobe Width 107 – ns

tDD Read Data Delay – 25 ns

tDRH Read Data Hold 5 – ns

WRITE (See Notes 1, 2, 3, 4, 5, and 6)

tAS Address Setup 5 – ns

tAH Address Hold 15 – ns

tCS Chip Select Setup 0 – ns

tCH Chip Select Hold 10 – ns

tWT HWT# Strobe Width 178 – ns

tDS Write Data Setup (see Note 4) – 61 ns

tDWH Write Data Hold (see Note 5) 5 – ns

Notes:

1. When the host executes consecutive Rx FIFO reads, a minimum delay of 2 times the internal CPU clock cycle plus

15 ns (85.86 ns at 28.224 MHz) is required from the falling edge of HRD# to the falling edge of the next Host Rx

FIFO HRD# clock.

2. When the Host executes consecutive Tx FIFO writes, a minimum delay of 2 times the internal CPU clock cycle plus

15 ns (85.86 ns at 28.224 MHz) is required from the falling edge of HWT# to the falling edge of the next Host Tx

FIFO HWT# clock.

3. tRD, tWT = tCYC + 15 ns.

4. tDS is measured from the point at which both HCS# and HWT# are active.

5. tDWH is measured from the point at which either HCS# and HWT# become inactive.

6. Clock frequency = 28.224 MHz clock.

SmartSCM Modem Data Sheet

3-36 Conexant 100490C

tAS tAH

tCS tCH

tRD

tDD tDRH

HA[2-0]

HCS#

HRD#

HWT#

HD[7-0]

tAS tAH

tCS tCH

HA[2-0]

tWT

tDS tDWH

HCS#

HRD#

HWT#

HD[7-0]

100491 F3-10 WF-HB

a. Host Read

b. Host Write

Figure 3-10. Waveforms - Parallel Host Bus

SmartSCM Modem Data Sheet

100490C Conexant 3-37

Serial DTE Interface

The serial DTE interface waveforms for 4800 and 9600 bps are illustrated in Figure 3-11.

TXCLK

4800 BPS

TXD

4800 BPS

TXCLK

9600 BPS

TXD

9600 BPS

NOTE: THIS FIGURE IS VALID FOR SYNCHRONOUS MODE ONLY. THERE IS NO RELATIONSHIP BETWEEN

NOTE: TXD AND TXCLK IN ASYNCHRONOUS MODE.

RXCLK

4800 BPS

RXD

4800 BPS

RXCLK

9600 BPS

RXD

9600 BPS

NOTE: THIS FIGURE IS VALID FOR SYNCHRONOUS MODE ONLY. THERE IS NO RELATIONSHIP BETWEEN

NOTE: RXD AND RXCLK IN ASYNCHRONOUS MODE.

a. Transmit

b. Receive

1227F3-14 WF-Ser DTE

Figure 3-11. Waveforms - Serial DTE Interface

SmartSCM Modem Data Sheet

3-38 Conexant 100490C

This page is intentionally blank.

SmartSCM Modem Data Sheet

100490C Conexant 4-1

4 PACKAGE DIMENSIONS

The 128-pin TQFP package dimensions are shown in Figure 4-1.

The 32-pin TQFP package dimensions are shown in Figure 4-2.

DD1

E1 DETAIL A

DETAIL A

Millimeters

0.05

21.75

15.75

0.5

0.17

0.11

1.6 MAX

0.15

1.4 REF

22.25

20.0 REF

18.5 REF

16.25

14.0 REF

12.5 REF

0.75

1.0 REF

0.50 BSC

0.27

0.17

0.08 MAX

0.0020

0.8563

0.6201

0.0197

0.0067

0.0043

Coplanarity

Min. Max. Min. Max.

Inches*

Dim.

Ref: 128-PIN TQFP (GP00-D264)

* Metric values (millimeters) should be used for

PCB layout. English values (inches) are

converted from metric values and may include

round-off errors.

0.0630 MAX

0.0059

0.0551 REF

0.8760

0.7874 REF

0.7283 REF

0.6398

0.5512 REF

0.4921 REF

0.0295

0.0394 REF

0.0197 BSC

0.0106

0.0067

0.0031 MAX

PD-TQFP-128 (040395)

PIN 1

REF

Figure 4-1. Package Dimensions - 128-Pin TQFP

SmartSCM Modem Data Sheet

4-2 Conexant 100490C

DETAIL A

Millimeters

0.05

8.75

0.5

0.30

0.13

1.6 MAX

0.15

1.4 REF

9.25

7.0 REF

5.6 REF

0.75

1.0 REF

0.80 BSC

0.40

0.19

0.10 MAX

0.0020

0.3445

0.0197

0.0118

0.0051

Coplanarity

Min. Max. Min. Max.

Inches*

Dim.

Ref: 32-PIN TQFP (GP00-D262)

* Metric values (millimeters) should be used for

PCB layout. English values (inches) are

converted from metric values and may include

round-off errors.

0.0630 MAX

0.0059

0.0551 REF

0.3642

0.2756 REF

0.2205 REF

0.0295

0.0394 REF

0.0315 BSC

0.0157

0.0075

0.004 MAX

PD-TQFP-32 (040395)

DETAIL A

DD2

PIN 1

REF

Figure 4-2. Package Dimensions - 32-pin TQFP

SmartSCM Modem Data Sheet

100490C Conexant 5-1

5 PARALLEL HOST INTERFACE

The modem supports a 16550A interface in parallel interface versions. The 16550A interface can operate in FIFO mode or

non-FIFO mode. Non-FIFO mode is the same as 16450 interface operation. FIFO mode unique operations are identified.

5.1 Overview

The parallel interface registers and the corresponding bit assignments are shown in Table 5-1.

The modem emulates the 16450/16550A interface and includes both a 16-byte receiver data first-in first-out buffer (RX FIFO)

and a 16-byte transmit data first-in first-out buffer (TX FIFO). When FIFO mode is selected in the FIFO Control Register

(FCR0 = 1), both FIFOs are operative. Furthermore, when FIFO mode is selected, DMA operation of the FIFO can also be

selected (FCR3 = 1). When FIFO mode is not selected, operation is restricted to 16450 interface operation.

The received data is read by the host from the Receiver Buffer (RX Buffer). The RX Buffer corresponds to the Receiver Buffer

Register in a 16550A device. In FIFO mode, the RX FIFO operates transparently behind the RX Buffer. Interface operation is

described with reference to the RX Buffer in both FIFO and non-FIFO modes.

The transmit data is loaded by the host into the Transmit Buffer (TX Buffer). The TX Buffer corresponds to the Transmit

Holding Register in a 16550A device. In FIFO mode, the TX FIFO operates transparently behind the TX Buffer. Interface

operation is described with reference to the TX Buffer in both FIFO and non-FIFO modes.

SmartSCM Modem Data Sheet

5-2 Conexant 100490C

Table 5-1. Parallel Interface Registers

No. Name 7654321 0

7 Scratch Register (SCR) Scratch Register

6 Modem Status Register

(MSR)

Data

Carrier

Detect

(DCD)

Ring

Indicator

(RI)

Data Set

Ready

(DSR)

Clear to

Send

(CTS)

Delta Data

Carrier

Detect

(DDCD)

Trailing

Edge of

Ring

Indicator

(TERI)

Delta Data

Set Ready

(DDSR)

Delta Clear

to Send

(DCTS)

5 Line Status Register (LSR) RX FIFO

Error

Transmitter

Empty

(TEMT)

Transmitter

Buffer

Empty

(THRE)

Break

Interrupt

(BI)

Framing

Error

(FE)

Parity

Error

(PE)

Overrun

Error

(OE)

Receiver

Data

Ready

(DR)

4 Modem Control Register

(MCR)

0 0 0 Local

Loopback

Out 2 Out 1 Request to

Send

(RTS)

Data

Terminal

Ready

(DTR)

3 Line Control Register

(LCR)

Divisor

Latch

Access Bit

(DLAB)

Set Break Stick Parity Even Parity

Select

(EPS)

Parity

Enable

(PEN)

Number of

Stop Bits

(STB)

Word

Length

Select Bit 1

(WLS1)

Word

Length

Select Bit 0

(WLS0)

2 Interrupt Identify Register

(IIR) (Read Only)

FIFOs

Enabled

FIFOs

Enabled

0 0 Pending

Interrupt ID

Bit 2

Pending

Interrupt ID

Bit 1

Pending

Interrupt ID

Bit 0

“0" if

Interrupt

Pending

2 FIFO Control Register

(FCR) (Write Only)

Receiver

Trigger

MSB

Receiver

Trigger

LSB

Reserved Reserved DMA Mode

Select

TX FIFO

Reset

RX FIFO

Reset

FIFO

Enable

(DLAB = 0)

Interrupt Enable Register

(IER)

0 0 0 0 Enable

Modem

Status

Interrupt

(EDSSI)

Enable

Receiver

Line Status

Interrupt

(ELSI)

Enable

Transmitter

Holding

Empty

Interrupt

(ETBEI)

Enable

Received

Data

Available

Interrupt

(ERBFI)

(DLAB = 0)

Transmitter Buffer

Transmitter FIFO Buffer Register (Write Only)

(DLAB = 0)

Receiver Buffer Register

(RBR)

Receiver FIFO Buffer Register (Read Only)

(DLAB = 1)

Divisor Latch MSB

(DLAB = 1)

Divisor Latch LSB Register

(DLL)

Divisor Latch LSB

SmartSCM Modem Data Sheet

100490C Conexant 5-3

5.2 Register Signal Definitions

5.2.1 IER - Interrupt Enable Register (Addr = 1, DLAB = 0)

The IER enables five types of interrupts that can separately assert the HINT output signal (Table 5-2). A selected interrupt

can be enabled by setting the corresponding enable bit to a 1, or disabled by setting the corresponding enable bit to a 0.

Disabling an interrupt in the IER prohibits setting the corresponding indication in the IIR and assertion of HINT. Disabling all

interrupts (resetting IER0 - IER3 to a 0) inhibits setting of any Interrupt Identifier Register (IIR) bits and inhibits assertion of the

HINT output. All other system functions operate normally, including the setting of the Line Status Register (LSR) and the

Modem Status Register (MSR).

Bits 7-4 Not used.

Always 0.

Bit 3 Enable Modem Status Interrupt (EDSSI).

This bit, when a 1, enables assertion of the HINT output whenever the Delta CTS (MSR0), Delta DSR (MSR1),

Delta TER (MSR2), or Delta DCD (MSR3) bit in the Modem Status Register (MSR) is a 1. This bit, when a 0,

disables assertion of HINT due to setting of any of these four MSR bits.

Bit 2 Enable Receiver Line Status Interrupt (ELSI).

This bit, when a 1, enables assertion of the HINT output whenever the Overrun Error (LSR1), Parity Error

(LSR2), Framing Error (LSR3), or Break Interrupt (LSR4) receiver status bit in the Line Status Register (LSR)

changes state. This bit, when a 0, disables assertion of HINT due to change of the receiver LSR bits 1-4.

Bit 1 Enable Transmitter Holding Register Empty Interrupt (ETBEI).

This bit, when a 1, enables assertion of the HINT output when the Transmitter Empty bit in the Line Status

Bit 0 Enable Receiver Data Available Interrupt (ERBFI) and Character Timeout in FIFO Mode.

This bit, when a 1, enables assertion of the HINT output when the Receiver Data Ready bit in the Line Status

HINT due to the LSR0 or character timeout.

SmartSCM Modem Data Sheet

5-4 Conexant 100490C

5.2.2 FCR - FIFO Control Register (Addr = 2, Write Only)

The FCR is a write-only register used to enable FIFO mode, clear the RX FIFO and TX FIFO, enable DMA mode, and set the

RX FIFO trigger level.

Bits 7-6 RX FIFO Trigger Level.

FCR7 and FCR6 set the trigger level for the RX FIFO (Receiver Data Available) interrupt.

FCR7 FCR6 RX FIFO Trigger Level (Bytes)

00 01

01 04

10 08

11 14

Bits 5-4 Not used.

Bit 3 DMA Mode Select.

When FIFO mode is selected (FCR0 = 1), FCR3 selects non-DMA operation (FCR3 = 0) or DMA operation

(FCR3 = 1). When FIFO mode is not selected (FCR0 = 0), this bit is not used (the modem operates in non-

DMA mode in 16450 operation).

DMA operation in FIFO mode.

RXRDY will be asserted when the number of characters in the RX FIFO is equal to or greater than the value in

the RX FIFO Trigger Level (IIR0-IIR3 = 4h) or the received character timeout (IIR0-IIR3 = Ch) has occurred.

RXRDY will go inactive when there are no more characters in the RX FIFO.

TXRDY will be asserted when there are one or more empty (unfilled) locations in the TX FIFO. TXRDY will go

inactive when the TX FIFO is completely full.

Non-DMA operation in FIFO mode.

RXRDY will be asserted when there are one or more characters in the RX FIFO. RXRDY will go inactive when

there are no more characters in the RX FIFO.

TXRDY will be asserted when there are no characters in the TX FIFO. TXRDY will go inactive when the first

character is loaded into the TX FIFO Buffer.

Bit 2 TX FIFO Reset.

When FCR2 is a 1, all bytes in the TX FIFO are cleared. This bit is cleared automatically by the modem.

Bit 1 RX FIFO Reset.

When FCR1 is a 1, all bytes in the RX FIFO are cleared. This bit is cleared automatically by the modem.

Bit 0 FIFO Enable.

When FCR0 is a 0, 16450 mode is selected and all bits are cleared in both FIFOs. When FCR0 is a 1, FIFO

mode (16550A mode) is selected and both FIFOs are enabled. FCR0 must be a 1 when other bits in the FCR

are written or they will not be acted upon.

SmartSCM Modem Data Sheet

100490C Conexant 5-5

5.2.3 IIR - Interrupt Identifier Register (Addr = 2)

The Interrupt Identifier Register (IIR) identifies the existence and type of up to five prioritized pending interrupts. Four priority

levels are set to assist interrupt processing in the host. The four levels, in order of decreasing priority, are: Highest: Receiver

Line Status, 2: Receiver Data Available or Receiver Character Timeout, 3: TX Buffer Empty, and 4: Modem Status.

When the IIR is accessed, the modem freezes all interrupts and indicates the highest priority interrupt pending to the host.

Any change occurring in interrupt conditions are not indicated until this access is complete.

Bits 7-6 FIFO Mode.

These two bits copy FCR0.

Bits 5-4 Not Used.

Always 0.

Bits 3-1 Highest Priority Pending Interrupt.

These three bits identify the highest priority pending interrupt (Table 5-2). Bit 3 is applicable only when FIFO

mode is selected, otherwise bit 3 is a 0.

Bit 0 Interrupt Pending.

When this bit is a 0, an interrupt is pending; IIR bits 1-3 can be used to determine the source of the interrupt.

When this bit is a1, an interrupt is not pending.

Table 5-2. Interrupt Sources and Reset Control

Interrupt Identification Register Interrupt Set and Reset Functions

Bit 3

(Note 1)

Bit 2 Bit 1 Bit 0 Priority

Level

Interrupt Type Interrupt Source Interrupt Reset Control

0 0 0 1 — None None —

0 1 1 0 Highest Receiver Line

Status

Overrun Error OE (LSR1),

Parity Error (PE) (LSR2),

Framing Error (FE) (LSR3),

or Break Interrupt (BI) (LSR4)

Reading the LSR

0 1 0 0 2 Received Data

Available

Received Data Available (LSR0) or RX

FIFO Trigger Level (FCR6-FCR7)

Reached1

Reading the RX Buffer or

the RX FIFO drops below

the Trigger Level

1 1 0 0 2 Character Time-

out Indication 1

The RX FIFO contains at least 1

character and no characters have been

removed from or input to the RX FIFO

during the last 4 character times.

Reading the RX Buffer

0 0 1 0 3 TX Buffer Empty TX Buffer Empty Reading the IIR or writing

to the TX Buffer

0 0 0 0 4 Modem Status Delta CTS (DCTS) (MSR0),

Delta DSR (DDSR) (MSR1),

Trailing Edge Ring Indicator (TERI)

(MSR3), or Delta DCD (DCD) (MSR4)

Reading the MSR

Notes:

1. FIFO Mode only.

SmartSCM Modem Data Sheet

5-6 Conexant 100490C

5.2.4 LCR - Line Control Register (Addr = 3)

The Line Control Register (LCR) specifies the format of the asynchronous data communications exchange.

Bit 7 Divisor Latch Access Bit (DLAB).

This bit must be set to a 1 to access the Divisor latch registers during a read or write operation. It must be

reset to a 0 to access the Receiver Buffer, the Transmitter Buffer, or the Interrupt Enable Register.

Bit 6 Set Break.

When bit 6 is a 1, the transmit data is forced to the break condition, i.e., space (0) is sent. When bit 6 is a 0,

break is not sent. The Set Break bit acts only on the transmit data and has no effect on the serial in logic.

Bit 5 Stick Parity.

When parity is enabled (LCR3 = 1) and stick parity is selected (LCR5 = 1), the parity bit is transmitted and

checked by the receiver as a 0 if even parity is selected (LCR4 = 1) or as a 1 if odd parity is selected (LCR4 =

0). When stick parity is not selected (LCR3 = 0), parity is transmit and checked as determined by the LCR3

and LCR4 bits.

Bit 4 Even Parity Select (EPS).

When parity is enabled (LCR3 = 1) and stick parity is not selected (LCR5 = 0), the number of 1s transmitted or

checked by the receiver in the data word bits and parity bit is either even (LCR4 = 1) or odd (LCR4 = 0).

Bit 3 Enable Parity (PEN).

When bit 3 is a 1, a parity bit is generated in the serial out (transmit) data stream and checked in the serial in

(receive) data stream as determined by the LCR 4 and LCR5 bits. The parity bit is located between the last

data bit and the first stop bit.

Bit 2 Number of Stop Bits (STB).

This bit specifies the number of stop bits in each serial out character. If bit 2 is a 0, one stop bit is generated

regardless of word length. If bit 2 is a 1 and 5-bit word length is selected, one and one-half stop bits are

generated. If bit 2 is a 1 and a 6-, 7-, or 8-bit word length is selected, two stop bits are generated. The serial in

logic checks the first stop bit only, regardless of the number of stop bits selected.

Bits 1-0 Word Length Select (WLS0 and WLS1).

These two bits specify the number of bits in each serial in or serial out character. The encoding of bits 0 and 1

is:

Bit 1 Bit 0 Word Length

0 0 5 Bits (Not supported)

0 1 6 Bits (Not supported)

10 7 Bits

11 8 Bits

SmartSCM Modem Data Sheet

100490C Conexant 5-7

5.2.5 MCR - Modem Control Register (Addr = 4)

The Modem Control Register (MCR) controls the interface with the modem or data set.

Bit 7-5 Not used.

Always 0.

Bit 4 Local Loopback.

When this bit is set to a 1, the diagnostic mode is selected and the following occurs:

1. Data written to the Transmit Buffer is looped back to the Receiver Buffer.

2. The DTS (MCR0), RTS (MCR1), Out1 (MCR2), and Out2 (MCR3) modem control register bits are

internally connected to the DSR (MSR5), CTS (MSR4), RI (MSR6), and DCD (MSR7) modem status

Bit 3 Output 2.

When this bit is a 1, HINT is enabled. When this bit is a 0, HINT is in the high impedance state.

Bit 2 Output 1.

This bit is used in local loopback (see MCR4).

Bit 1 Request to Send (RTS).

This bit controls the Request to Send (RTS) function. When this bit is a 1, RTS is on. When this bit is a 0, RTS

is off.

Bit 0 Data Terminal Ready (DTR).

This bit controls the Data Terminal Ready (DTR) function. When this bit is a 1, DTR is on. When this bit is a 0,

DTR is off.

SmartSCM Modem Data Sheet

5-8 Conexant 100490C

5.2.6 LSR - Line Status Register (Addr = 5)

This 8-bit register provides status information to the host concerning data transfer.

Bit 7 RX FIFO Error.

In the 16450 mode, this bit is not used and is always 0.

In the FIFO mode, this bit is set if there are one or more characters in the RX FIFO with a parity error, framing

error, or break indication detected. This bit is reset to a 0 when the host reads the LSR and none of the above

conditions exist in the RX FIFO.

Bit 6 Transmitter Empty (TEMT).

This bit is set to a 1 whenever the TX Buffer (THR) and equivalent of the Transmitter Shift Register (TSR) are

both empty. It is reset to a 0 whenever either the THR or the equivalent of the TSR contains a character.

In the FIFO mode, this bit is set to a 1 when ever the TX FIFO and the equivalent of the TSR are both empty.

Bit 5 Transmitter Holding Register Empty (THRE) [TX Buffer Empty].

This bit, when set, indicates that the TX Buffer is empty and the modem can accept a new character for

transmission. In addition, this bit causes the modem to issue an interrupt to the host when the Transmit

Holding Register Empty Interrupt Enable bit (IIR1) is set to 1. The THRE bit is set to a 1 when a character is

transferred from the TX Buffer. The bit is reset to 0 when a byte is written into the TX Buffer by the host.

In the FIFO mode, this bit is set when the TX FIFO is empty; it is cleared when at least one byte is in the TX

FIFO.

Bit 4 Break Interrupt (BI).

This bit is set to a 1 whenever the received data input is a space (logic 0) for longer than two full word lengths

plus 3 bits. The BI bit is reset when the host reads the LSR.

Bit 3 Framing Error (FE).

This bit indicates that the received character did not have a valid stop bit. The FE bit is set to a 1 whenever

the stop bit following the last data bit or parity bit is detected as a logic o (space). The FE bit is reset to a 0

when the host reads the LSR.

In the FIFO mode, the error indication is associated with the particular character in the FIFO it applies to; the

FE bit is set to a 1 when this character is loaded into the RX Buffer.

Bit 2 Parity Error (PE).

This bit indicates that the received data character in the RX Buffer does not have the correct even or odd

parity, as selected by the Even Parity Select bit (LCR4) and the Stick Parity bit (LCR5). The PE bit is reset to a

0 when the host reads the LSR.

In the FIFO mode, the error indication is associated with the particular character in the it applies to; the PE bit

is set to a 1 when this character is loaded into the RX Buffer.

Bit 1 Overrun Error (OE).

This bit is set to a 1 whenever received data is loaded into the RX Buffer before the host has read the

previous data from the RX Buffer. The OE bit is reset to a 0 when the host reads the LSR.

In the FIFO mode, if data continues to fill beyond the trigger level, an overrun condition will occur only if the

RX FIFO is full and the next character has been completely received.

Bit 0 Receiver Data Ready (DR).

This bit is set to a 1 whenever a complete incoming character has been received and has been transferred

into the RX Buffer. The DR bit is reset to a 0 when the host reads the RX Buffer.

In the FIFO mode, the DR bit is set when the number of received data bytes in the RX FIFO equals or

exceeds the trigger level specified in FCR0-FCR1.

SmartSCM Modem Data Sheet

100490C Conexant 5-9

5.2.7 MSR - Modem Status Register (Addr = 6)

The Modem Status Register (MSR) reports current state and change information of the modem. Bits 4-7 supply current state

and bits 0-3 supply change information. The change bits are set to a 1 whenever a control input from the modem changes

state from the last MSR read by the host. Bits 0-3 are reset to 0 when the host reads the MSR or upon reset.

Whenever bits 0, 1, 2, or 3 are set to a 1, a Modem Status Interrupt (IIR0-IIR3 = 0) is generated.

Bit 7 Data Carrier Detect (DCD).

This bit indicates the logic state of the DCD# (RLSD#) output. If Loopback is selected (MCR4 = 1), this bit

reflects the state of the Out2 bit in the MCR (MCR3).

Bit 6 Ring Indicator (RI).

This bit indicates the logic state of the RI# output. If Loopback is selected (MCR4 = 1), this bit reflects the

state of the Out1 bit in the MCR (MCR2).

Bit 5 Data Set Ready (DSR).

This bit indicates the logic state of the DSR# output. If Loopback is selected (MCR4 = 1), this bit reflects the

state of the DTR bit in the MCR (MCR0).

Bit 4 Clear to Send (CTS).

This bit indicates the logic state of the CTS# output. If Loopback is selected (MCR4 = 1), this bit reflects the

state of the RTS bit in the MCR (MCR1).

Bit 3 Delta Data Carrier Detect (DDCD).

This bit is set to a 1 when the DCD bit changes state since the MSR was last read by the host.

Bit 2 Trailing Edge of Ring Indicator (TERI).

This bit is set to a 1 when the RI bit changes from a 1 to a 0 state since the MSR was last read by the host.

Bit 1 Delta Data Set Ready (DDSR).

This bit is set to a 1 when the DSR bit has changed since the MSR was last read by the host.

Bit 0 Delta Clear to Send (DCTS).

This bit is set to a 1 when the CTS bit has changed since the MSR was last read by the host.

5.2.8 RBR - RX Buffer (Receiver Buffer Register) (Addr = 0, DLAB = 0)

The RX Buffer (RBR) is a read-only register at location 0 (with DLAB = 0). Bit 0 is the least significant bit of the data, and is

the first bit received.

5.2.9 THR - TX Buffer (Transmitter Holding Register) (Addr = 0, DLAB = 0)

The TX Buffer (THR) is a write-only register at address 0 when DLAB = 0. Bit 0 is the least significant bit and the first bit sent.

5.2.10 Divisor Registers (Addr = 0 and 1, DLAB = 1)

The Divisor Latch LS (least significant byte) and Divisor Latch MS (most significant byte) are two read-write registers at

locations 0 and 1 when DLAB = 1, respectively.

The baud rate is selected by loading each divisor latch with the appropriate hex value.

Programmable values corresponding to the desired baud rate are listed in Table 5-3.

5.2.11 SCR - Scratch Register (Addr = 7)

The Scratchpad Register is a read-write register at location 7. This register is not used by the modem and can be used by the

host for temporary storage.

SmartSCM Modem Data Sheet

5-10 Conexant 100490C

Table 5-3. Programmable Baud Rates

Divisor Latch (Hex)

MS LS Divisor (Decimal) Baud Rate

06 00 1536 75

04 17 1047 110

03 00 768 150

01 80 384 300

00 C0 192 600

00 60 96 1200

00 30 48 2400

00 18 24 4800

00 0C 12 9600

00 06 6 19200

00 04 4 28800

00 03 3 38400

00 02 2 57600

00 01 1 115200

00 00 NA 230400

5.3 Receiver FIFO Interrupt Operation

5.3.1 Receiver Data Available Interrupt

When the FIFO mode is enabled (FCR0 = 1) and receiver interrupt (RX Data Available) is enabled (IER0 = 1), receiver

interrupt operation is as follows:

1. The Receiver Data Available Flag (LSR0) is set as soon as a received data character is available in the RX FIFO. LSR0

is cleared when the RX FIFO is empty.

2. The Receiver Data Available interrupt code (IIR0-IIR4 = 4h) is set whenever the number of received data bytes in the RX

FIFO reaches the trigger level specified by FCR6-FCR7 bits; it is cleared whenever the number of received data bytes in

the RX FIFO drops below the trigger level specified by FCR6-FCR7 bits.

3. The HINT interrupt is asserted whenever the number of received data bytes in the RX FIFO reaches the trigger level

specified by FCR6-FCR7 bits. HINT interrupt is de-asserted when the number of received data bytes in the RX FIFO

drops below the trigger level specified by FCR6-FCR7 bits.

5.3.2 Receiver Character Timeout Interrupts

When the FIFO mode is enabled (FCR0 = 1) and receiver interrupt (Receiver Data Available) is enabled (IER0 = 1), receiver

character timeout interrupt operation is as follows:

1. A Receiver character timeout interrupt code (IIR0-IIR3 = Ch) is set if at least one received character is in the RX FIFO,

the most recent received serial character was longer than four continuous character times ago (if 2 stop bits are

specified, the second stop bit is included in this time period), and the most recent host read of the RX FIFO was longer

than four continuous character times ago.

5.4 Transmitter FIFO Interrupt Operation

5.4.1 Transmitter Empty Interrupt

When the FIFO mode is enabled (FCR0 = 1) and transmitter interrupt (TX Buffer Empty) is enabled (IER0 = 1), transmitter

interrupt operation is as follows:

1. The TX Buffer Empty interrupt code (IIR0-IIR3 = 2h) will occur when the TX Buffer is empty; it is cleared when the TX

Buffer is written to (1 to 16 characters) or the IIR is read.

2. The TX Buffer Empty indications will be delayed 1 character time minus the last stop bit time whenever the following

occur: THRE = 1 and there have not been at least two bytes at the same time in the TX FIFO Buffer since the last setting

of THRE was set. The first transmitter interrupt after setting FCR0 will be immediate.

NOTES

Further Information

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