1300 Henley Court Pullman, WA 99163 509.334.6306 www.store.digilent.com Basys MX3TM Board Reference Manual Revised April 21, 2017 This manual applies to the Basys MX3 rev. B Table of Contents Table of Contents .................................................................................................................. 1 Overview............................................................................................................................... 5 Software Support ........................................................................................................................ 6 Coursework and Additional Materials ........................................................................................ 6 1 Programming the Board ................................................................................................. 7 1.1 Programming Tools .......................................................................................................... 7 1.2 Programming Basics ......................................................................................................... 8 1.3 Digital Inputs and Outputs ............................................................................................... 9 1.4 Remappable Pins ............................................................................................................ 10 1.5 CPU Clock Source ........................................................................................................... 11 2 Power Supplies ............................................................................................................ 12 3 User LEDs ..................................................................................................................... 13 4 3.1 Connectivity.................................................................................................................... 14 3.2 Functionality ................................................................................................................... 14 User Switches .............................................................................................................. 14 4.1 Connectivity.................................................................................................................... 15 4.2 Functionality ................................................................................................................... 16 4.3 Shared Pins ..................................................................................................................... 16 DOC#: 410-336 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 1 of 56 Basys MX3TM Board Reference Manual 5 6 7 8 9 User Buttons ................................................................................................................ 16 5.1 Connectivity.................................................................................................................... 17 5.2 Functionality ................................................................................................................... 17 5.3 Shared Pins ..................................................................................................................... 18 RGB LED ....................................................................................................................... 18 6.1 Connectivity.................................................................................................................... 19 6.2 Functionality ................................................................................................................... 19 6.2.1 RGB LED Implemented Using PWM ........................................................................ 19 6.2.2 RGB LED Implemented Using PDM ......................................................................... 20 Seven-segment Display ................................................................................................ 20 7.1 Connectivity.................................................................................................................... 22 7.2 Functionality ................................................................................................................... 23 LCD Module ................................................................................................................. 24 8.1 Connectivity.................................................................................................................... 25 8.2 Functionality ................................................................................................................... 26 I2C Interface ................................................................................................................. 27 10 Accelerometer ............................................................................................................. 28 10.1 Connectivity ................................................................................................................ 28 10.2 Functionality ............................................................................................................... 28 10.3 Shared Pins ................................................................................................................. 29 11 Serial Peripheral Interface ............................................................................................ 29 11.1 SPI1 ............................................................................................................................. 29 11.2 SPI2 ............................................................................................................................. 29 12 Flash Memory .............................................................................................................. 30 12.1 Connectivity ................................................................................................................ 30 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 2 of 56 Basys MX3TM Board Reference Manual 12.2 Functionality ............................................................................................................... 31 13 UART ........................................................................................................................... 31 13.1 Connectivity ................................................................................................................ 32 13.2 Functionality ............................................................................................................... 32 14 Motor Driver ................................................................................................................ 32 14.1 Connectivity ................................................................................................................ 33 14.2 Functionality ............................................................................................................... 35 15 Servo Headers .............................................................................................................. 35 15.1 Connectivity ................................................................................................................ 36 15.2 Functionality ............................................................................................................... 36 15.3 Shared Pins ................................................................................................................. 37 16 IrDA Module ................................................................................................................ 37 16.1 Connectivity ................................................................................................................ 37 16.2 Functionality ............................................................................................................... 38 17 Audio Out .................................................................................................................... 39 17.2 Connectivity ................................................................................................................ 39 17.2 Functionality ............................................................................................................... 40 18 Microphone ................................................................................................................. 40 18.1 Connectivity ................................................................................................................ 41 18.2 Functionality ............................................................................................................... 41 19 Analog Input Control .................................................................................................... 42 19.1 Connectivity ................................................................................................................ 42 19.2 Functionality ............................................................................................................... 43 20 Pmod Connectors ......................................................................................................... 43 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 3 of 56 Basys MX3TM Board Reference Manual 21 Analog Discovery Debug Header ................................................................................... 45 Appendix 1: Remappable Input Pins .................................................................................... 47 Appendix 2: Remappable Output Pins .................................................................................. 49 Appendix 3: Basys MX3 Pinout ............................................................................................ 53 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 4 of 56 Basys MX3TM Board Reference Manual Overview The Basys MX3 is a true MCU trainer board designed from the ground up around the teaching experience. Basys MX3 features the PIC32MX370 from Microchip and was designed to be used with the MPLAB(R) X IDE. With an exhaustive set of peripherals, students gain exposure to a wide range of embedded systems related concepts while using a professional grade tool set. Accompanied by free and open source coursework, including seven in-depth teaching units and 15 complete labs, the Basys MX3 is a versatile MCU trainer board ideal for teaching introductory embedded systems courses. The Basys MX3. Power: Powered from USB or any 5V external power source USB and Debugging: USB-UART Bridge USB programmer/debugger 30-pin Analog Discovery 2 connector PIC32MX370F512L Microcontroller MIPS32(R) M4K(R) core runs up to 96 MHz using onboard 8 MHz oscillator 512 KB of Program Flash Memory, 12 KB of Boot Flash Memory 128 KB of SRAM Four Direct Memory Access (DMA) Modules Two SPI, Two IC, and Five UART serial interfaces Parallel Master Port (PMP) for graphics interfaces Five 16-bit Timers/Counters Five Input Capture Modules Five Output Compare Modules 85 I/O pins o 54 pins support Peripheral Pin Select (PPS) for function remapping Switches, Push-buttons, LEDs, and Displays: 5 Push-buttons 1 Reset button 8 Slide switches 8 LEDs 1 RGB LED 4-digit 7-segment display LCD character display Expansion Connectors: Two standard Pmod ports o 16 Total microcontroller I/O One I2C Connector o 2 Total microcontroller I/O Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Audio, Motor Control, and Other Devices: Speaker with Audio Output Jack and volume control Microphone with volume control Dual H-Bridge Motor Driver for up to two 1.5 A Brushed DC Motors or one stepper motor 2 Servo Connectors FIR-compatible IrDA Module Potentiometer 3-axis, 12-bit accelerometer 4 MB SPI Flash Page 5 of 56 Basys MX3TM Board Reference Manual Software Support The Basys MX3 is fully supported by Microchip's MPLAB X IDE. See section 1 on Programming the Board for more information on using the Basys MX3 in MPLAB X IDE. Digilent provides a set of libraries called the Basys MX3 Library Pack that adds support for all onboard peripherals. This library pack can be downloaded from the Basys MX3 Resource Center. The Basys MX3 can also be used in Arduino IDE once the Digilent Core for Arduino IDE has been installed. Instructions for installing the Digilent Core for Arduino IDE can be found on the Basys MX3 Resource Center. Coursework and Additional Materials Basys MX3 comes with a complete set of coursework designed to give teaching professionals flexibility in designing embedded systems and other microprocessor courses. With almost 300 pages of material, "Embedded Systems Basys MX3 and PIC32MX370" covers topics from toggling LEDs, motor control, and introduction to digital signal processing. Access to the full coursework is available on the Basys MX3 Resource Center. Links to additional materials from Digilent and Microchip, including the Basys MX3 schematic and the PIC32MX370F512L datasheet, can also be found on the Basys MX3 Resource Center. The Basys MX3 uses a lot of devices to implement all of the functionality it provides (accelerometer, flash memory, motor driver, IRDA, etc.). The manufacturers of each of these devices provide detailed descriptions of their functionality in their datasheets. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 6 of 56 Basys MX3TM Board Reference Manual 1 Programming the Board 1.1 Programming Tools The Basys MX3 can be used with Microchip's standard MPLAB X IDE. This software suite can be downloaded for free from the Microchip website and includes a free evaluation copy of the XC32 compiler for use with the PIC32 microcontroller family. MPLAB X IDE is the tool used to write, compile, program, and debug code running on the Basys MX3 board. Programming and debugging a program on the Basys MX3 using the MPLAB X IDE is possible using the DEBUG USB connector. The board contains all the required circuitry for MPLAB X to communicate with the onboard PIC32, so no additional programming tools need to be purchased. When creating a new project in MPLAB X, a wizard allows you to setup the environment and device specific tools. The steps for this include the following: 1. Select Microchip Embedded / Standalone Project, then use the "Select Device" option to specify the PIC32 microcontroller being used: PIC32MX370F512L. 2. Select the programming tool named Basys MX3 corresponding to the board you want to program, under Licensed Debugger group. Figure 1.1. MPLAB X tool selection. 3. Select the compiler you want to use. Figure 1.2. MPLAB X compiler selection. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 7 of 56 Basys MX3TM Board Reference Manual Another useful tool included with MPLAB X is MPLAB X IPE. This tool allows the direct programming/erasing of the microcontroller, but it does not provide an environment for writing, compiling, or debugging the code. Please see Microchip documentation for instructions on using this tool. 1.2 Programming Basics It is often very helpful to include the xc.h header when writing code for the Basys MX3: #include <xc.h> This further provides the inclusion of another header (p32mx370f512l.h) into the project that provides useful definitions such as: Register names o example (register LATA is set to 0): LATA = 0; Specific register bits that can be accessed using a structure having the name of the register suffixed by "bits". o example (bit LATA1 of the register LATA is set to 1): LATAbits.LATA1 = 1; Digilent provides a set of libraries called the Basys MX3 Library Pack that addresses much of the functionality on the Basys MX3: ACL (accelerometer) ADC (analog-to-digital converter) AUDIO BTN (buttons) IRDA LCD LED MIC (microphone) MOT (motors) PMODS RGBLED SPIFLASH SSD SWT (switches) UART These libraries are wrappers over the lower level functions that access the registers, allowing the user to call the functionality using functions like: LED_Init(); LED_SetValue(4, 1); //turn on LED4 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 8 of 56 Basys MX3TM Board Reference Manual This set of libraries comes with the user documentation, but this is what you must do in order to use them: Include in your project the .c and .h files corresponding to the module you want to use (for example led.c and led.h). In your code, include the header of the module: #include "led.h" 1.3 In your code, call the needed functions Digital Inputs and Outputs The PIC32MX370F512L microcontroller offers access to all the board resources through its pins, so understanding how to access their features is very important. The list that describes each pin functionality is included in Appendix 3. You can see that each pin may have multiple functions, but all pins have one feature in common: they have an associated digital I/O (input/output) bit. On PIC32 microcontrollers, the I/O pins are grouped into I/O Ports and are accessed via peripheral registers in the microcontroller. There are seven I/O Ports numbered A-G and each is 16 bits wide. Depending on the PIC32 microcontroller, some of the I/O Ports are not present, and not all 16 bits are accessible in all I/O Ports. Each I/O Port has the following control registers: TRIS, LAT, PORT, ANSEL, CNPU, CNPD, and ODC. The registers for each I/O Port are named after it: TRISx, LATx, PORTx, ANSELx, CNPUx, CNPDx and ODCx. For example, port A will have the following assigned registers: TRISA, LATA, etc. The TRIS register is used to set the pin direction. Setting a TRIS bit to 0 makes the corresponding pin an output. Setting the TRIS bit to 1 makes the pin an input. The LAT register is used to write to the I/O Port. Writing to the LAT register sets any pins configured as outputs. Reading from the LAT register returns the last value written. The PORT register is used to read from the I/O Port. Reading from the PORT register returns the current state of all the pins in the I/O Port. Writing to the PORT register may not produce the expected result, therefore writing to LAT register is recommended. To summarize: write using LAT, read using PORT. PIC32 microcontrollers allow any pin set as an output to be configured as either a normal digital output or as an open-drain output. The ODC register is used to control the output type. Setting an ODC bit to 0 makes the pin a normal output and setting it to 1 makes the pin an open-drain output. The multifunction pins that include analog input functionality need to be configured in order to be used as digital pins by clearing the corresponding bit from ANSEL register. These pins will include ANx in their name. For example: AN11/PMA12/RB11 for RB11. This microcontroller has a weak pull-up and a weak pull-down connected to each pin. These pull-ups and pulldowns are enabled/disabled by setting the corresponding bits from CNPU and CNPD registers to 1/0. The default setting is 0 (pull-ups and pull-downs disabled). You can see a typical example of I/O pin configuration as output and digital output operations in the User LEDs section. You can see a typical example of I/O pin configuration as input (including analog disable) and digital input operations in the User Buttons section. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 9 of 56 Basys MX3TM Board Reference Manual Refer to the PIC32MX3XX/4XX Family Datasheet, and the PIC32 Family Reference Manual, Section 12, IO Ports, for more detailed information about the operation of the I/O Ports in the microcontroller. 1.4 Remappable Pins Users may independently map the input and/or output of most digital peripherals to a fixed subset of digital I/O pins. Pins that support the peripheral pin select feature include the designation "RPn" in their full pin designation, where "RP" designates a remappable peripheral and "n" is the remappable port number. The available peripherals to be mapped are digital-only. These include general serial communications (UART and SPI), general purpose timer clock inputs, timer-related peripherals (input capture and output compare), and interrupt-on-change inputs. On the other hand, some peripheral modules cannot be included in the peripheral pin select feature because it requires special I/O circuitry on a specific port and it cannot be easily connected to multiple pins. These modules include I2C and analog-to-digital converters (ADC), among others. Peripheral pin select features are controlled using two sets of Special Function Registers (SFRs): one to map peripheral inputs, and one to map peripheral outputs. The peripheral inputs are mapped and named from the peripheral perspective (based on the peripheral). The [pin name]R registers, where [pin name] refers to the specific peripheral pins, are used to configure peripheral input mapping. TABLE 12-1 in the PIC32MX370F512L datasheet from Microchip (and Appendix 1 in this document) shows the different pins and their values available to assign to a peripheral pin. The following example shows how different I/Os, such as pin RF4, can be assigned to U1RX input pin of the UART1 peripheral: U1RXR = 0x02; // 0010 corresponds to RF4 Figure 1.3. Remappable input example. The peripheral outputs are mapped and named from the pin perspective (on the basis of the pin). The RPnR registers (Register 12-2) are used to control output mapping. The PIC32MX370F512L datasheet details in TABLE 122 (and Appendix 2 in this document) the values corresponding to each IO pin, associated to each available peripheral pin. Note that the current version of the Basys MX3 schematic (B.0) incorrectly lists RD6 and RD7 as remappable pins (RPD6 and RPD7, respectively); these pins are not remappable on the PIC32MX370F512L. The following example shows how different peripheral outputs, such as U3TX, can be assigned to pin RF4: Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 10 of 56 Basys MX3TM Board Reference Manual RPF4R = 0x01; // 0001 corresponds to U3TX Figure 1.4. Remappable output example. Input and output remapping is illustrated in the SPI2 section, where the SPI2 pins are mapped over the pins of PMOD A connector. 1.5 CPU Clock Source The PIC32 microcontroller supports numerous clock source options for the main processor operating clock. The Basys MX3 uses an 8 MHz external crystal for use with the XT oscillator option. Oscillator options are selected via the configuration settings specified using the #pragma config statement. Use #pragma config POSCMOD=XT to select the XT option. Using the internal system clock phase-locked loop (PLL), it is possible to select numerous multiples or divisions of the 8 MHz oscillator to produce CPU operating frequencies up to 80 MHz. The clock circuit PLL provides an input divider, multiplier, and output divider. The external clock frequency (8 MHz) is first divided by the input divider value selected. This is multiplied by the selected multiplier value and then finally divided by the selected output divider. The result is the system clock, SYSCLK, frequency. The SYSCLK frequency is used by the CPU, DMA controller, interrupt controller, and pre-fetch cache. The values controlling the operating frequency are specified using the PIC32MX370 configuration variables. These are set using the #pragma config statement. Use #pragma config FPLLIDIV to set the input divider, #pragma config FPLLMUL to set the multiplication factor, and #pragma config FPLLODIV to set the output divider. Refer to the PIC32MX3XX/4XX Family Datasheet and the PIC32MX Family Reference Manual, Section Oscillators, for information on how to choose the correct values, as not all combinations of multiplication and division factors will work. In addition to configuring the SYSCLK frequency, the peripheral bus clock, PBCLK, frequency is also configurable. The peripheral bus clock is used for most peripheral devices; particularly the clock used by the timers and serial controllers (UART, SPI, I2C). The PBLCK frequency is a division of the SYSCLK frequency selected using #pragma config FPBDIV. The PBCLK divider can be set to divide by 1, 2, 4, or 8. The following example will set up the Basys MX3 for operation with a SYSCLK frequency of 80 MHz and a PBCLK frequency of 80 MHz. #pragma config FNOSC = FRCPLL #pragma config FSOSCEN = OFF Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 11 of 56 Basys MX3TM Board Reference Manual #pragma config POSCMOD = #pragma config OSCIOFNC = #pragma config FPBDIV = XT ON DIV_1 #pragma config FPLLIDIV = #pragma config FPLLMUL = #pragma config FPLLODIV = 2 DIV_2 MUL_20 DIV_1 Power Supplies The Basys MX3 requires a 5V power source to operate. This power source can come from the Programming / Debugging USB port (J12), the USB-UART (J10), or from an external 5V DC power supply that's connected to Power Jack (J11). These three power inputs are connected through Schottky diodes to form the primary input power network, VIN, which is used to power the onboard regulators and the majority of the onboard peripherals. No jumper is required to select the input power source. The board will automatically power on while the Power Switch (SW8) is in the on position and power is present on any of the power inputs. A power-good LED (LD11), driven by the output of the 3.3V regulator (LMR10515), indicates that the board is receiving power and that the onboard supplies are functioning as expected. An overview of the Basys MX3 power circuit is shown in Fig 2.1. VEXT (0 - 11V) JP1 VM 1 Motor Driver IC7: DRV8835 Terminal Block (J5) 1 J1 Servo Headers 1 5V Input Power Jack (J11) Micro-USB Port (J12) DEBUG VBAR J2 VU5V0 DBG_5V0 VIN + - VIN ON/OFF IC10: LMR10515 FT_5V0 VIN Power Switch (SW8) VCC3V3 EN PWR_ON Micro-USB Port (J10) UART 1.5A VIN VOUT Power On LED (LD11) DBG3V3 ON IC11: LP2985IM5-3.3 Figure 2.1. Power supply circuit. The USB port(s) can deliver enough power for most designs; however, a few demanding applications, including any that drive multiple peripheral boards, may require more power than a USB port can provide. In these instances, an external power supply can be used. Due to their high current demands, motors and servos cannot be powered through either of the USB ports, and may only be powered through an external supply. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 12 of 56 Basys MX3TM Board Reference Manual An external power supply can be used by plugging into Power Jack J11. The supply must use a coaxial, centerpositive 2.0 mm internal-diameter plug, and provide a voltage of 5V DC (4.75V minimum, 5.5V maximum). The supply should provide a minimum current of 2A if servos are to be used. Ideally, the supply should be capable of provide 20 Watts of power (5V DC, 4A). Many suitable supplies can be purchased from Digilent or other catalog vendors. The onboard motor driver (Texas Instruments DRV8835) may be powered by a 5V supply connected to Power Jack J11, or by an external supply (0V-11V) connected to pins 1 and 2 of Terminal Block J5. Jumper JP1 is used to select which power source is used by the motor driver. Supply Circuits 3.3V (VCC3V3) 3.3V (DBG3V3) PIC32MX370, PMODs, and all onboard peripherals excluding the LCD backlight, RGB LED, IrDA LED, Servos, and Motors Onboard Microchip Programmer/Debugger Device Current (max/typical) IC10: Texas Instruments LMR10515 1.5A/NA IC11: Texas Instruments LP2985IM5-3.3 150mA/NA Table 2.1. Power rail characteristics. 3 User LEDs Eight LEDs are provided, labeled LD0 - LD7 on the board (and LED0 - LED7 on the schematic), attached to eight digital I/O pins. Controlling the LEDs is done by basic access to an output I/O pin. Read more details in the Digital Inputs and Outputs section. Figure 3.1 shows the way the LEDs are electrically connected on the Basys MX3. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 13 of 56 Basys MX3TM Board Reference Manual Figure 3.1. LED schematic diagram. 3.1 Connectivity Label LD0 LD1 LD2 LD3 LD4 LD5 LD6 LD7 Schematic name LED0 LED1 LED2 LED3 LED4 LED5 LED6 LED7 PIC32 pin Description TMS/CTED1/RA0 TCK/CTED2/RA1 SCL2/RA2 SDA2/RA3 TDI/CTED9/RA4 TDO/RA5 TRCLK/RA6 TRD3/CTED8/RA7 Led 0 Led 1 Led 2 Led 3 Led 4 Led 5 Led 6 Led 7 Table 3.1. LED connectivity. All the pins must be defined as digital output (their corresponding TRIS bit must be set to 0): TRISAbits.TRISA<0-7> = 0; // LED<0-7> configured as output 3.2 Functionality To turn an LED on or off, turn the corresponding digital output pin high or low by writing 1 or 0 to the corresponding LATA register bit. LATAbits.LATA<0-7> = 1; // turn led on or LATAbits.LATA<0-7> = 0; // turn led off Library functions for using the LEDs are contained in the Basys MX3 library pack, LED library; however, the user can easily use the LEDs without the LED library, as presented above. 4 User Switches Eight switches are provided, labeled SW0 - SW7 on the board and in the schematic, attached to eight digital I/O pins of the PIC32. Reading the switches is done by basic access to an input I/O pin. Read more details in Digital Inputs and Outputs section. Figure 4.1 shows the way the switches are electrically connected on the Basys MX3. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 14 of 56 Basys MX3TM Board Reference Manual Figure 4.1. Switches schematic diagram. 4.1 Connectivity Pin Shared With Label Schematic Name PIC32 Pin SW0 SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW0 SW1 SW2 SW3 SW4 SW5 SW6 SW7 RPF3/RF3 RPF5/PMA8/RF5 RPF4/PMA9/RF4 RPD15/RD15 RPD14/RD14 AN11/PMA12/RB11 CVREFOUT/AN10/RPB10/CTED11PMA13/RB10 AN9/RPB9/CTED4/RB9 TRIG_2 Description Switch 0 Switch 1 Switch 2 Switch 3 Switch 4 Switch 5 Switch 6 Switch 7 Table 4.1. Switches connectivity. All the pins must be defined as digital input: their corresponding TRIS bit must be set to 1, and analog function must be disabled for pins routed to SW5, SW6, and SW7. TRISFbits.TRISF3 = 1; // RF3 (SW0) configured as input TRISFbits.TRISF5 = 1; // RF5 (SW1) configured as input TRISFbits.TRISF4 = 1; // RF4 (SW2) configured as input TRISDbits.TRISD15 = 1; // RD15 (SW3) configured as input TRISDbits.TRISD14 = 1; // RD14 (SW4) configured as input TRISBbits.TRISB11 = 1; // RB11 (SW5) configured as input ANSELBbits.ANSB11 = 0; // RB11 (SW5) disabled analog TRISBbits.TRISB10 = 1; // RB10 (SW6) configured as input ANSELBbits.ANSB10 = 0; // RB10 (SW6) disabled analog Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 15 of 56 Basys MX3TM Board Reference Manual 4.2 TRISBbits.TRISB9 = 1; // RB9 (SW7) configured as input ANSELBbits.ANSB9 = 0; // RB9 (SW7) disabled analog Functionality In order to read the switches, the user needs to read the corresponding digital input pin. A value of 1 indicates the switch as being on (high) or 0 indicates the switch as being off (low). val = PORTFbits.RF3; // read SW0 val = PORTFbits.RF5; // read SW1 val = PORTFbits.RF4; // read SW2 val = PORTDbits.RD15; // read SW3 val = PORTDbits.RD14; // read SW4 val = PORTBbits.RB11; // read SW5 val = PORTBbits.RB10; // read SW6 val = PORTBbits.RB9; // read SW7 Library functions for using the switches are contained in the Basys MX3 library pack, SWT library; however, the user can easily use the switches without the SWT library, as presented above. 4.3 Shared Pins As shown in the connectivity table above, SW7 driving signal is shared with the TRIG_2 signal in 2x15 pins Debug Header. 5 User Buttons There are five buttons on the board, labeled BTNU, BTNL, BTNC, BTNR, BTND both on the board and in the schematic, attached to five digital I/O pins of PIC32. Reading the buttons is done by basic access to an input I/O pin. Read more details in Digital Inputs and Outputs section. Figure 5.1 shows the way the buttons are electrically connected on the Basys MX3. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 16 of 56 Basys MX3TM Board Reference Manual Figure 5.1. Button schematic diagram. The Basys MX3 also has a red button labeled RESET. This button is connected directly to the MCLR pin of the PIC32 and will trigger it to be reset. 5.1 Connectivity Label BTNU BTNL BTNC BTNR BTND Schematic Name BTNU BTNL BTNC BTNR BTND PIC32 Pin PGEC1/AN1/RPB1/CTED12/RB1 PGED1/AN0/RPB0/RB0 RPF0/PMD11/RF0 AN8/RPB8/CTED10/RB8 RPA15/RA15 Pin Shared With PGC PGD TRIG_1 S0_PWM S1_PWM Description Button up Button left Button center Button right Button down Table 5.1. Button connectivity. All the pins must be defined as digital input: their corresponding TRIS bit must be set to 1, and analog function must be disabled for pins corresponding to BTNU, BTNL, BTNR, BTND. TRISBbits.TRISB1 = 1; // RB1 (BTNU) configured as input ANSELBbits.ANSB1 = 0; // RB1 (BTNU) disabled analog TRISBbits.TRISB0 = 1; // RB1 (BTNL) configured as input ANSELBbits.ANSB0 = 0; // RB1 (BTNL) disabled analog TRISFbits.TRISF4 = 1; // RF0 (BTNC) configured as input TRISBbits.TRISB8 = 1; // RB8 (BTNR) configured as input 5.2 ANSELBbits.ANSB8 = 0; // RB8 (BTNR) disabled analog TRISAbits.TRISA15 = 1; // RA15 (BTND) configured as input Functionality To read the buttons, the user needs to read the corresponding digital input pin, a value of 1 indicating the button is pressed or 0 indicating the button is released: Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 17 of 56 Basys MX3TM Board Reference Manual val = PORTBbits.RB1; // read BTNU val = PORTBbits.RB0; // read BTNL val = PORTFbits.RF0; // read BTNC val = PORTBbits.RB8; // read BTNR val = PORTAbits.RA15; // read BTND Please note that if you want the buttons to trigger a specific functionality, proper software debouncing is required. Library functions for using the buttons are contained in the Basys MX3 library pack, BTN library; however, the user can easily use the buttons without the BTN library, as presented above. 5.3 Shared Pins As shown in the connectivity Table 5.1 above, some pins are shared: Buttons BTNL and BTNU share functions with PGD and PGC signals used for programming. Therefore, the following line should be inserted in the code, to disable their programming function. #pragma config JTAGEN = OFF 6 Buttons BTNR and BTND share the pins with S0_PWM and S1_PWM, explained in Servo headers section, so these resources should be used exclusively. BTNC is shared with TRIG_1 signal in 2x15 Pins Debug Header, so it can be used to trigger events in an Analog Discovery board experiment. RGB LED The Basys MX3 board contains one tri-color (RGB) LED. The LED allows the user to obtain any RGB color by configuring the R, G and B color components. Figure 6.1. RGB LED schematic diagram. The usage of the RGB LED is the same as controlling three separate LEDs, one for each color. Figure 6.1 shows the way the RGB LED is electrically connected on the Basys MX3. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 18 of 56 Basys MX3TM Board Reference Manual There is one digital signal to control each color component. Using either 0 or 1 values for these signals will only give the user a limited number of colors (two colors for each component), so most of the time this is not enough in applications using the RGB feature. The solution is to send a sequence of 1 and 0 values on these digital lines, switched rapidly with a frequency higher than human perception. The "duty factor" will finally determine the color, as the human eye will "integrate" the discrete illumination values into the final color sensation. The most used approach in solving this problem is the use of pulse-width modulation (PWM) signals. Another approach is the use of pulse-density modulation (PDM). These methods are explained in the RGB LED Implemented Using PWM and RGB LED Implemented Using PDM sections. 6.1 Connectivity Label Schematic Name PIC32 Pin R LED8_R AN25/RPD2/RD2 G LED8_G RPD12/PMD12/RD12 B LED8_B AN26/RPD3/RD3 Description Signal corresponding to the R component of the RGB Signal corresponding to the G component of the RGB Signal corresponding to the R component of the RGB Table 6.1. RGB LED connectivity. 6.2 Functionality 6.2.1 RGB LED Implemented Using PWM The percentage of each period that the pulse is high determines the signals "duty cycle". Figure 6.2 shows how different duty cycles are implemented using PWM. Figure 6.2. PWM duty cycle. Using this method, the intensity of each component of the RGB LED is determined by the duty cycle being applied. PWM is most often implemented in the microcontroller using the output compare (OC) peripheral modules along with a timer. One timer (Timer y) is assigned to the OC module. Setting the PRy register of the timer will set the PWM period. Setting the OCxRS register of the OC module will set the actual duty cycle. The PIC32 datasheet displayed in Fig. 6.3 below explains how one period of the PWM is generated. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 19 of 56 Basys MX3TM Board Reference Manual Figure 6.3. PIC32 PWM generation. The RGBLED library from the Basys MX3 library pack contains a commented example of PWM implementation with the following features: LED8_R, LED8_G, and LED8_B are mapped to OC3, OC5, and OC4. OC3, OC5, and OC4 are properly configured, together with assigned Timer 2. When a new color is set, its components (R, G, and B) are assigned to OC3RS, OC5RS, and OC4RS. 6.2.2 RGB LED Implemented Using PDM PDM method adjusts both the frequency and length of the "High" pulses in the modulated signal. A PDM is implemented using a register and an accumulator adder with carry output. The n-bit register can store any binary value from 0 to 2 - 1. In each clock period, the register content is added to the accumulator. The carry bit (overflow of the n-bit accumulator) is the output. It is "High" as often as the accumulator overflows, so that when large values are added, carry will occur often. The "High" pulse is only 1 clock period long, but more "High" pulses can succeed when the register content is close to maximum. The RGBLED library from the Basys MX3 library pack contains an example of PDM implementation, with the following features: 7 LED8_R, LED8_G, and LED8_B are configured as simple digital outputs. Timer 5 is configured to generate an interrupt every approx. x us. Three 16-bit accumulators are used, one for each color. In the interrupt service routine, for each color, the 8-bit color value is added to the corresponding 16-bit accumulator. For each color, the 9th bit of the accumulator is considered the carry bit. The resulted carry bits are assigned to LED8_R, LED8_G, and LED8_B. For each color, the accumulator is masked so that it only contains an 8-bit value (carry is cleared). Seven-segment Display The Basys MX3 board contains a four-digit common anode seven-segment LED display. Each of the four digits is composed of seven segments displaying a "figure 8" pattern and a decimal point with an LED embedded in each segment. Segment LEDs can be individually illuminated. Of the number of possible patterns, the ten corresponding to the decimal digits are the most useful. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 20 of 56 Basys MX3TM Board Reference Manual Figure 7.1. Seven-segment schematic diagram. The anodes of the seven LEDs forming each digit are tied together into one "common anode" circuit node, but the LED cathodes remain separate, as shown in Fig. 7.2. The common anode signals are available as four "digit enable" input signals to the 4-digit display. The cathodes of similar segments on all four displays are connected into seven circuit nodes labeled CA through CG (so, for example, the four "D" cathodes from the four digits are grouped together into a single circuit node called "CD"). These seven cathode signals are available as inputs to the 4-digit display. This signal connection scheme creates a multiplexed display, where the cathode signals are common to all digits but they can only illuminate the segments of the digit whose corresponding anode signal is asserted. Figure 7.2. Seven-segment digits. To illuminate a segment, the anode should be driven high while the cathode is driven low; however, since the Basys MX3 uses transistors to drive enough current into the common anode point, the anode enables are inverted. Therefore, both the AN0 ... AN3 and the CA ... G/DP signals are driven low when active. Figure 7.3. Common anode circuit node. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 21 of 56 Basys MX3TM Board Reference Manual A scanning display controller circuit can be used to show a 4-digit number on this display. This circuit drives the anode signals and corresponding cathode patterns of each digit in a repeating, continuous succession at an update rate that is faster than the human eye can detect. Each digit is illuminated just one-fourth of the time, but because the eye cannot perceive the darkening of a digit before it is illuminated again, the digit appears continuously illuminated. If the update, or "refresh", rate is slowed to around 45Hz, a flicker can be noticed on the display. To make each of the four digits appear bright and continuously illuminated, all should be driven once every 1 to 16ms, with a refresh frequency of about 1kHz to 60Hz. For example, if every digit is refreshed every 3ms, corresponding to a frequency of 333Hz, the entire display will be refreshed every 12ms. The controller must drive low the cathodes with the correct pattern when the corresponding anode signal is driven high. To illustrate the process: 1. 2. 3. If AN0 is asserted while CB and CC are asserted, then a "1" will be displayed in digit position 1. If AN1 is asserted while CA, CB, and CC are asserted, a "7" will be displayed in digit position 2. If AN0, CB, and CC are driven for 4ms, and then AN1, CA, CB, and CC are driven for 4ms in an endless succession, the display will show "71" in the first two digits. An example timing diagram for a four-digit controller is shown in Fig. 7.4. Refresh period = 1ms to 16ms Digit period = Refresh / 4 AN0 AN1 AN2 AN3 Cathodes Digit 0 Digit 1 Digit 2 Digit 3 Figure 7.4. 4-digit scanning display controller timing diagram. Please note that the two dots (situated between the middle digits) are not connected. 7.1 Connectivity Name AN0 AN1 AN2 AN3 CA CB CC CD CE CF CG PIC32 Pin AN12/PMA11/RB12 AN13/PMA10/RB13 VREF-/CVREF-/PMA7/RA9 VREF+/CVREF+/PMA6/RA10 TRD1/RG12 RPA14/RA14 PMD14/RD6 TRD0/RG13 RG15 PMD15/RD7 PMD13/RD13 DP TRD2/RG14 Description Anode 0 pin Anode 1 pin Anode 2 pin Anode 3 pin Cathode A pin Cathode B pin Cathode C pin Cathode D pin Cathode E pin Cathode F pin Cathode G pin Cathode DP (decimal point) pin Table 7.1. Seven-segment connectivity. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 22 of 56 Basys MX3TM Board Reference Manual All the pins (AN0-3, CA-CG and DP) must be configured as digital output and Anode 0 and Anode 1 must have the analog functionality disabled: TRISBbits.TRISB12 = 0; //RB12 set as output ANSELBbits.ANSB12 = 0; //RB12 analog functionality disabled TRISBbits.TRISB13 = 0; //RB13 set as output ANSELBbits.ANSB13 = 0; //RB13 analog functionality disabled TRISAbits.TRISA9 = 0; //RA9 set as output TRISAbits.TRISA10 = 0; //RA10 set as output TRISGbits.TRISG12 = 0; //RG12 set as output TRISAbits.TRISA14 = 0; //RA14 set as output TRISDbits.TRISD6 = 0; //RD6 set as output TRISGbits.TRISG13 = 0; //RG13 set as output TRISGbits.TRISG15 = 0; //RG15 set as output TRISDbits.TRISD7 = 0; //RD7 set as output TRISDbits.TRISD13 = 0; //RD13 set as output TRISGbits.TRISG14 = 0; //RG14 set as output 7.2 Functionality A seven-segment display controller is implemented in the SSD library of the Basys MX3 library pack. Here are some details on the implementation of the library: One array contains constant values for the segment's configurations (one bit for each segment) corresponding to various digits (0-9, A-F). When the user selects the values to be displayed, they are used as index into this segment's configuration table and the resulting configuration bytes are stored in global variables. Timer1 is used to generate interrupts every 3ms (corresponding to the period register PR1 = 3750). Every time the interrupt handler routine is called, the following operations are performed: o The next digit becomes the current digit, in a circular approach (thus each digit will be addressed once after 4 calls of the interrupt handler routine). o All digits are deactivated by outputting 1 to their corresponding anodes. o The cathodes are outputted according to the segment's information corresponding to the current digit. o The current digit is activated (0 is outputted to its corresponding anode). Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 23 of 56 Basys MX3TM Board Reference Manual 8 LCD Module The Basys MX3 features a basic LCD module, the Sunlike Display SD1602H with a KS0066U display controller. It displays two rows of 16 characters. It is controlled using a set of command signals (DISP_RS, DISP_R/W, DISP_EN) and 8 data signals (DB0 - DB7). These signals make up a parallel port for communicating with the display. The board also provides a switch to turn on and off the LCD display backlight, situated on the bottom right corner of the LCD display. Figure 8.1. LCD schematic diagram. The LCD display is controlled by a set of commands written to the device. Also, read commands provide the ability to read status and data. Please read the SD1602H datasheet for a detailed list of read and write commands. The LCD display requires a specific initialization sequence, also detailed in the datasheet. The device features two types of memory: CGRAM and DDRAM. The LCD controller contains a character-generator ROM (CGROM) with 192 preset 5x8 character patterns, a character-generator RAM (CGRAM) that can hold 8 user-defined 5x8 characters, and a display data RAM (DDRAM) that can hold 80 character codes. Character codes written into the DDRAM serve as indexes into the CGROM (or CGRAM). Writing a character code into a particular DDRAM location will cause the associated character to appear at the corresponding display location. Display positions can be shifted left or right by setting a bit in the instruction register (IR). The write-only IR directs display operations (such as clear display, shift left or right, set DDRAM address, etc.). A busy flag shows whether the display has completed the last requested operation; prior to initiating a new operation, the flag can be checked to see if the previous operation has been completed. The display has more DDRAM locations than can be displayed at any given time. DDRAM locations 00H to 27H map to the first display row, and locations 40H to 67H map to the second row. Normally, DDRAM location 00H maps to the upper left display corner (the "home" location), and 40H to the lower left. Shifting the display left or right can change this mapping. The display uses a temporary data register (DR) to hold data during DDRAM /CGRAM reads or writes, and an internal address register to select the RAM location. Address register contents, set via the instruction register, are automatically incremented after each read or write operation. The LCD display uses ASCII character codes. Codes up through 7F are standard ASCII (which includes all "normal" alphanumeric characters). Codes above 7F produce various international characters. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 24 of 56 Basys MX3TM Board Reference Manual The following timing diagrams detail how write and read processes must be implemented. The essential difference is the polarity of the DISP_RW signal (0 for write and 1 for read). For more detailed timing information, refer to the KS0066U datasheet. Figure 8.2. LCD write timing. Figure 8.3. LCD read timing. 8.1 Connectivity Name PIC32 Pin DISP_RS AN15/RPB15/OCFB/CTED6/PMA0/RB15 DISP_RW RPD5/PMRD/RD5 DISP_EN RPD4/PMWR/RD4 DB0 DB1 DB2 DB3 DB4 DB5 DB6 DB7 PMD0/RE0 PMD1/RE1 AN20/PMD2/RE2 RPE3/CTPLS/PMD3/RE3 AN21/PMD4/RE4 AN22/RPE5/PMD5/RE5 AN23/PMD6/RE6 AN27/PMD7/RE7 Description Register Select: High for Data Transfer, Low for Instruction Transfer. Read/Write signal: High for Read mode, Low for Write mode. Read/Write Enable: High for Read, falling edge writes data Data bits 0 -7. Table 8.1. LCD connectivity. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 25 of 56 Basys MX3TM Board Reference Manual The command pins (DISP_RS, DISP_RW and DISP_EN) must be defined as digital output with analog functionality disabled for DISP_RS: TRISBbits.TRISB15 = 0; // RB15 (DISP_RS) set as an output ANSELBbits.ANSB15 = 0; // disable analog functionality on RB15 (DISP_RS) TRISDbits.TRISD5 = 0; // RD5 (DISP_RW) set as an output TRISDbits.TRISD4 = 0; // RD4 (DISP_EN) set as an output The data pins (DB0 - DB7) must be set as digital pins, with the direction according to the type of operation (read / write). The analog functionality should also be disabled for DB2, DB4, DB5, DB6, and DB7. TRISEbits.TRISE0 = 1; // RE0 (DB0) set as input (change 1 to 0 for output/write functionality) TRISEbits.TRISE1 = 1; // RE1 (DB1) set as input (change 1 to 0 for output/write functionality) TRISEbits.TRISE2 = 1; // RE2 (DB2) set as input (change 1 to 0 for output/write functionality) ANSELEbits.ANSE20 = 0; // disable analog functionality on RE2 (DB2) TRISEbits.TRISE3 = 1; // RE3 (DB3) set as input (change 1 to 0 for output/write functionality) TRISEbits.TRISE4 = 1; // RE4 (DB4) set as input (change 1 to 0 for output/write functionality) ANSELEbits.ANSE21 = 0; // disable analog functionality on RE4 (DB4) TRISEbits.TRISE5 = 1; // RE5 (DB5) set as input (change 1 to 0 for output/write functionality) ANSELEbits.ANSE22 = 0; // disable analog functionality on RE5 (DB5) TRISEbits.TRISE6 = 1; // RE6 (DB6) set as input (change 1 to 0 for output/write functionality) ANSELEbits.ANSE23 = 0; // disable analog functionality on RE6 (DB6) TRISEbits.TRISE7 = 1; // RE7 (DB7) set as input (change 1 to 0 for output/write functionality) ANSELEbits.ANSE27 = 0; // disable analog functionality on RE7 (DB7) 8.2 Functionality The recommended approach to controlling the LCD module is to use the LCD library of the Basys MX3 library pack. Features implemented: Low level read and write functionality are implemented using command / data pins, according to the parallel port approach described above. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 26 of 56 Basys MX3TM Board Reference Manual 9 Basic commands are implemented using the low level read and write functions. The initialization sequence is implemented according to the implemented commands. Other functions include o Write to LCD screen. o Access the CGRAM and DDRAM memories. I2C Interface The inter-integrated circuit (I2C) interface provides a medium speed (100K or 400Kbps) synchronous serial communications bus. The I2C interface allows master and slave operation using either 7-bit or 10-bit device addressing. Each device is given a unique address, and the protocol can address packets to a specific device or to broadcast packets to all devices on the bus. Refer to the Microchip PIC32MX3XX/4XX Family Datasheet and the PIC32 Family Reference Manual for detailed information on configuring and using the I 2C interface. The PIC32MX370F512L microcontroller provides two independent I2C interfaces. The Basys MX3 is designed to offer dedicated access to one of these interfaces, I2C1 (pins SCL1 and SDA1), using the I2C daisy chain connector labeled I2C situated under the LCD. The other I2C interface, I2C2, is not available on the Basys MX3 board, since its pins (SCL2 and SDA2) are not wired to external connectors. As mentioned in Section 1.4 Remappable pins, I2C interfaces are not involved in pin remapping. The SCL1 and SDA1 don't need to be configured or managed, they are properly accessed through the I2C1 interface. The I2C daisy chain connector provides two positions each for connecting to the I2C signals, power and ground. By using two-wire or four-wire MTE cables (available separately from Digilent) a daisy chain of multiple I 2C-capable devices can be created. One onboard I2C device is connected on the I2C1 interface: the accelerometer. See the Accelerometer section for more information on its use. The I2C bus is an open-collector bus. Devices on the bus actively drive the signals low. The high state of the I2C signals is achieved by pull-up resistors when no device is driving the lines low. One device on the I2C bus must provide the pull-up resistors. On the Basys MX3, I2C1 has pull-up resistors attached to it. Generally, only one device on the bus will need to have the pull-ups enabled. Detailed information about the operation of the I 2C peripherals can be found in the PIC32 Family Reference Manual, Section 24, Inter-Integrated Circuit. The following table details the content of the I2C connector (the col1 and col2 columns correspond to the two parallel rows of pins): Label on the Board SCL SDA GND V Left Column SCL SDA GND 3V3 Right Column SCL SDA GND 3V3 PIC32 Pin SCL1/RG2 SDA1/RG3 GND VCC3V3 Table 9.1. I2C connector pinout. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 27 of 56 Basys MX3TM Board Reference Manual 10 Accelerometer Basys MX3 provides an onboard accelerometer: NXP's MMA8652FCR1. It is a 3-axis, 12-bit digital accelerometer, exposing an I2C digital interface. It is possible to use its ACL_INT2 pin for raising a programmable interrupt. The accelerometer is located on the top of the board; you can recognize the arrows that show the directions of the three axes. The Fig. 10.1 shows the way Accelerometer is controlled using digital signals. Figure 10.1. Accelerometer schematic diagram. 10.1 Connectivity The accelerometer is connected to SCL1 and SDA1 lines of the I2C1 interface. A general I/O signal is connected to INT2 pin. Schematic Name PIC32 pin Description SCL SCL1/RG2 I2C Clock signal SDA SDA1/RG3 I2C Data signal ACL_INT2 RPG0/PMD8/RG0 Programmable Interrupt Table 10.1. Accelerometer connectivity. 10.2 Functionality To use the accelerometer, proper I2C communication (read, write) must be implemented over I2C1. The I2C1 interface must be initialized, and then accessed through read and write functions. The I 2C device address of the accelerometer is 0x1D. Communication over the I2C is implemented in the ACL library of the Basys MX3 library pack. If the user wants to use the accelerometer without the ACL library, they must implement their own I2C functions. The accelerometer has a set of registers that can be written to configure the device and read to access the data collected by the accelerometer. Note that you can visualize the communication with the accelerometer by attaching a logic analyzer to the 8-pin I2C connector, located on the top of the board. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 28 of 56 Basys MX3TM Board Reference Manual Please read the MMA8652FCR1 documentation for more details. 10.3 Shared Pins The Accelerometer shares the I2C1 pins with other devices that can be connected using the interface connector (detailed in the I2C Interface section). 11 Serial Peripheral Interface Serial peripheral interface (SPI) is a four-wire synchronous serial interface and devices can operate as either an SPI master device or as an SPI slave device. The four SPI signals are generally called Slave Select (SS), Master Out Slave In (MOSI), Master In Slave Out (MISO), and Serial Clock (SCK). The master device generates MOSI, SS, and SCK. The SS signal is used to enable the slave device. It is only necessary to use a dedicated _SS signal when using the PIC32's SPI controller in slave mode, because in master mode any general purpose I/O pin can be used to generate SS. The PIC32MX370F512L microcontroller provides two serial peripheral interfaces: SPI1 and SPI2 (see SPI1 and SPI2 sections). These hardware interfaces implement the MOSI, MISO, and SCK behavior and leave SS to be handled by the user. The PIC32 microcontroller labels the SPI signals as: Slave Select (SS), Serial Data Out (SDO), Serial Data In (SDI), and Serial Clock (SCK). When the PIC32 microcontroller is enabled as a master device, SDO serves the purpose of MOSI and SDI serves the purpose of MISO. When the PIC32 microcontroller is operating as an SPI slave device, SDI serves the purpose of MOSI and SDO serves the purpose of MISO. Detailed information about the operation of the SPI peripherals can be found in the PIC32 Family Reference Manual, Section Serial Peripheral Interface. 11.1 SPI1 SPI1 is used for the onboard Flash memory. There is also a connector labeled SPI (J6) on the bottom that exposes the SPI1 signals. Assuming that another digital output pin is used for slave select, SPI1 signals can be used in order to connect another slave SPI device using this connector. Please read the Flash memory section for details about connecting to SPI1. 11.2 SPI2 It is possible to configure SPI2 to be accessed using the pins of PMOD A. The SPI2_SS, SPI2_SCK, and SPI2_SI pins should be configured as digital output, while the SPI2_SO pin must be configured as digital input. Note that RC1(SPI2_SI) and RC4 (SPI2_SO) need to be remapped to perform SDO2 and SDI2 functions. Also, note that the naming of the signals is reversed, as SPI2_SI and SPI2_SO are named from slave perspective, while SDO2 and SDI2 are named from the microcontroller perspective. PMODA pin JA1 JA2 JA3 Function SPI2_SS SPI2_SI SPI2_SO PIC32 pin RPC2/RC2 RPC1/RC1 RPC4/CTED7/RC4 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Needed mapping for SPI2 RPC1R = 0x06; // SDO2 - RC1 SDI2R = 0x0A; // SDI2 - RC4 Page 29 of 56 Basys MX3TM Board Reference Manual PMODA pin JA4 Function SPI2_SCK PIC32 pin AN16/C1IND/RPG6/SCK2/PMA5/RG6 Needed mapping for SPI2 Table 11.1. SPI connectivity. Communication over the SPI2 interface is implemented in the SPIJA library of the Basys MX3 library pack. If the user wants to use the SPI2 without the SPIJA library, they must define their own SPI functions. 12 Flash Memory The Basys MX3 comes with 4 MB of onboard flash memory. The part used is the Spansion S25FL132 and is an SPI memory. More information about the SPI interface is found in the Serial Peripheral Interface section. Figure 12.1 depicts the way the Flash memory is controlled by digital signals. Figure 12.1. Flash memory schematic diagram. It contains 1024 sectors of 4 KB, making the total capacity 4MB. The following table, shown in Table 12.1 extracted from the S25FL132K datasheet, shows the main memory address map. Sector Size 4 Sector Count 1024 Sector Range Address Range (Byte Address) SA0 000000h-000FFFh : SA1023 3FF000h-3FFFFFh Notes Sector Starting Address -Sector Ending Address Table 12.1. Flash address map. Please read the S25FL132K documentation for more details. 12.1 Connectivity The flash memory is connected to the following pins that provide access to the SPI1 interface. Note that RF2 (SPI_SI) and RF7 (SPI_SO) need to be remapped to perform SDO1 and SDI1 functions. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 30 of 56 Basys MX3TM Board Reference Manual The SPI_CE, SPI_SCK, and SPI_SI pins should be configured as digital output, while the SPI_SO pin must be configured as digital input. Name SPI_CE SPI_SI SPI_SO SPI_SCK Label on J6 CE SI SO SCK PIC32 pin RPF8/RF8 RPF2/RF2 RPF7/RF7 RPF6/SCK1/INT0/RF6 Needed mapping for SPI1 RPF2R = 0x08; // SDO1 - RF2 SDI1R = 0x0F; // SDI1 - RF7 Table 12.2. Flash connectivity. 12.2 Functionality To use the flash memory, the SPI pins must be properly configured to implement SPI1 functions (see Section 12.1 above). Then, proper SPI communication (read, write) must be implemented over SPI1. The SPI1 interface must be initialized and then accessed through read and write functions. Flash communication is implemented in the SPIFLASH library of the Basys MX3 library pack. If a user wants to use the SPI flash without the SPIFLASH library, they must implement their own SPI functions. Note that users can visualize the communication with the SPI flash using a connector labeled SPI (J6), located on the back of the board under PMOD A connector. 13 UART Figure 13.1. UART schematic diagram. The PIC32MX370F512L microcontroller provides five UART interfaces: UART1, UART2, ..., UART5. Each UART can provide either a 2-wire or a 4-wire asynchronous serial interface. The 2-wire interface uses only receive (RX) and transmit (TX) signals. The 4-wire interface includes request-to-send (RTS) and clear-to-send (CTS) in addition to receive and transmit signals. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 31 of 56 Basys MX3TM Board Reference Manual The Basys MX3 provides a USB to UART serial converter, via a micro-USB connector and uses UART_TX and UART_RX pins of the PIC32. These 2 pins can be mapped to implement UART4 or UART5 functionality. See Remappable pins section for more details about remapping. Besides the UART port mapped to the USB_UART interface, other UART interfaces can be mapped to the Pmod's pins, depending on the remappable functionality available. See Pmod Connectors for more details. 13.1 Connectivity The following table shows the signals that go to the USB-Serial module from PIC32. Name UART_TX UART_RX PIC32 pin RPF12/RF12 RPF13/RF13 Table 13.1. UART connectivity. The UART_TX must be defined as digital output and the UART_RX as a digital input: TRISFbits.TRISF12 = 0; //RF12 (UART_TX) set as an output TRISFbits.TRISF13 = 1; //RF13 (UART_RX) set as an input 13.2 Functionality The USB-UART converter module functionality is implemented in the UART library of the Basys MX3 library pack. Implementation features: USB-UART converter signals are mapped over the UART4 communication signals: o U4RXR = 0x09; // UART_RX (RF13) -> U4RX o RPF12R = 0x02; // UART_TX (RF12) -> U4TX Send and receive functions over UART are implemented in the library. If the users want to use the UART module without the UART library, they need to implement their own UART functionality. 14 Motor Driver The Basys MX3 features a Dual H-Bridge Motor Driver. The part used is the Texas Instruments DRV8835. It supports up to two 1.5A brushed DC motors or one stepper motor. The PIC32 uses 5 signals: MODE, AIN1, AIN2, BIN1, BIN2, to connect to the motor driver MODE, AIN1/APHASE, AIN2/AENBL, BIN1/BPHASE, BIN2/BENBL control pins. The Basys MX3 board provides a 6-pin wire-to-board terminal block that allows firm contact to the motor driver pins using a screwless, tension clamped connector labeled MOTOR OUT (J5 on the schematic). The control signals are labeled A1, A2, B1, B2, and they correspond to AOUT1, AOUT2, BOUT1, BOUT2 signals of motor driver. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 32 of 56 Basys MX3TM Board Reference Manual Figure 14.1. Motor driver schematic diagram. The MODE signal selects one of the two operating modes: logic low selects IN/IN mode, while logic high selects PH/EN mode. When using IN/IN mode, the logical values of AIN1, AIN2, BIN1, BIN2 control the 4 command signals of a stepper motor: A1, A2, B1, B2. When using PH/EN mode: AIN1, AIN2 signals (through their APHASE, AENABLE functions) control the Phase (direction) and Enable of the H Bridge - the DC motor A (outputs A1, A2) driver BIN1, BIN2 signals (through their BPHASE, BENABLE function) control the Phase (direction) and Enable of the H Bridge - the DC motor B (outputs B1, B2) driver. The voltage on the output pins A1, A2, B1, B2 is dependent of the motor supply power applied to the motor controller. It is possible to use the VBAR power pin (5V - the power from the external barrel), or an external power supplied by the user using the VEXT / GND pins of the MOTOR OUT connector block (0V to 11V). These two options are selectable using the MOTOR PWR jumper block (situated just above the MOTOR OUT connector). Using the motors with the jumper on the VBAR position requires external power source connected to the barrel power connector. The Table 14.1 details the usage of the MOTOR PWR jumper block: Jumper position VBAR VEXT Description The power provided from the external power supply (using the barrel connector) is used for motors. The power VEXT provided from an external supply (using the VEXT pin of the MOTOR OUT connector block) is used for motors. Table 14.1. Motor power selection. Please read the Texas Instruments DRV8835 datasheet for more details about the motor controller. 14.1 Connectivity Table 14.2 shows the signals connecting the Motor Driver to the PIC32. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 33 of 56 Basys MX3TM Board Reference Manual Name PIC32 pin Motor Driver pin MODE RPF1/PMD10/RF1 MODE AIN1 PGED3/AN3/C2INA/RPB3/RB3 AIN1/APHASE AIN2 RPE8/RE8 AIN2/AENBL BIN1 RPE9/RE9 BIN1/BPHASE BIN2 AN5/C1INA/RPB5/RB5 BIN2/BENBL Description logic low selects IN/IN mode logic high selects PH/EN mode IN/IN mode: Logic high sets AOUT1 high PH/EN mode: Sets direction of H-bridge A IN/IN mode: Logic high sets AOUT2 high PH/EN mode: Logic high enables H-bridge A IN/IN mode: Logic high sets BOUT1 high PH/EN mode: Sets direction of H-bridge B IN/IN mode: Logic high sets BOUT2 high PH/EN mode: Logic high enables H-bridge B Table 14.2. Motor connectivity. The command pins (MODE, AIN1, AIN2, BIN1, BIN2) must be defined as digital output and the analog functionality for AIN1 and BIN2 disabled: TRISFbits.TRISF1 = 0; //set RF1 (MODE) to be an output TRISBbits.TRISB3 = 0; //set RB3 (AIN1) to be an output ANSELBbits.ANSB3 = 0; //disable analog functionality for RB3 (AIN1) TRISEbits.TRISE8 = 0; //set RE8 (AIN2) to be an output TRISEbits.TRISE9 = 0; //set RE9 (BIN1) to be an output TRISBbits.TRISB5 = 0; //set RB5 (BIN2) to be an output ANSELBbits.ANSB5 = 0; //disable analog functionality for RB5 (BIN2) The following signals are routed to the MOTOR_OUT board to wire connector: Connector Label Motor Driver pin Description VEXT - The external power that can be applied to the motors, selected using MOTOR PWR jumper block (0 to 11 Volts) GND - The GND for the external power applied on VEXT A1 AOUT1 IN/IN mode: Signal 1 of the stepper motor PH/EN mode: Signal 1 of the DC motor A A2 AOUT2 IN/IN mode: Signal 2 of the stepper motor PH/EN mode: Signal 2 of the DC motor A B1 BOUT1 IN/IN mode: Signal 3 of the stepper motor PH/EN mode: Signal 1 of the DC motor B B2 AOUT2 IN/IN mode: Signal 4 of the stepper motor PH/EN mode: Signal 2 of the DC motor B Table 14.3. Motor connector pinout. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 34 of 56 Basys MX3TM Board Reference Manual 14.2 Functionality The control of Motor module is implemented in the MOT library of the Basys MX3 library pack. Features of the implementation: Mode selection is implemented by setting the digital output MODE pin. Separate functionalities are implemented, corresponding to the two modes: IN/IN and PH/EN. in IN/IN mode, the 4 control pins AIN1, AIN2, BIN1, BIN2 are used as digital outputs, in this manner: o They are initialized in a (1, 1, 0, 0) configuration, considered an unsigned hexadecimal value 0x0C. o To perform stepper motor steps, the configuration value is rotated left or right (according to the motor's direction) with the desired number of steps. In PH/EN mode, the AIN1 and BIN1 are used as outputs, while the AIN2 and BIN2 are mapped to OC2 and OC3 modules, which are configured to generate PWM signals. The control of the 2 DC motors is done like this: o The direction is set to digital output AIN1 (DC motor A) or BIN1 (DC motor B) o The speed of the motor is implemented by loading the OC2RS (DC motor A) or OC3RS (DC motor B) registers with the desired values If the user wants to use the Motor driver module without the MOT library, they must implement their own Motor driver control functionality and can use the code in the library as a reference. 15 Servo Headers Figure 15.1. Servo header schematic diagram. The Basys MX3 provides two 3-pin servo headers, labeled SERVO 0 and SERVO 1. Servo motors are designed to move to a precise desired position and then stop, and are composed of a control board, motor, sense potentiometer, and gears that connect the motor and output shaft. A digital signal is sent to the control board which then drives the motor until the sense potentiometer verifies that the output shaft is in the correct position. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 35 of 56 Basys MX3TM Board Reference Manual All servos come with three wires: power, ground, and control. Pulses are sent via the control wire and a pulsewidth modulation signal controls the direction and degree of rotation. Usually servos are designed with limited rotation angles like 60, 90, 180, and so on. Using the control signals exposed by the two servo connectors, called S0_PWM and S1_PWM, the PIC32 can command the servos attached to the two connectors. Since the control should use the PWM functionality, these pins need to be mapped over output compare modules OC5 and OC4. Each servo motor connector exposes the barrel voltage (5V) together with the GND. This means using the servo headers requires that an external power supply is connected to the barrel power connector. 15.1 Connectivity Table 15.1 below shows the content of the two servo headers, providing details on S0_PWM and S1_PWM signals. Connector Label on the Servo Connector PWM VBAR Signal Name PIC32 pin Description S0_PWM VBAR AN8/RPB8/CTED10/RB8 The control signal for servo 0 The power VBAR (5V) and GND provided from the external power supply (using the barrel connector), to be used for servo 0 The control signal for servo 1 The power VBAR (5V) and GND provided from the external power supply (using the barrel connector), to be used for servo 1 SERVO 0 GND GND PWM VBAR S1_PWM VBAR GND GND RPA15/RA15 SERVO 1 Table 15.1. Servo header connectivity. The S0_PWM and S1_PWM pins will be used as digital output pins: The corresponding TRIS bit must be set to 0: TRISBbits.TRISB8 = 0; TRISAbits.TRISA15 = 0; The ANSEL bit corresponding to S0_PWM should be set to 0: ANSELBbits.ANSB8 = 0; 15.2 Functionality Servo motor driver functionality is implemented in the SRV library of the Basys MX3 library pack. Implementation features include: RB8 is mapped to OC5 RPB8R = 0x0B; // 1011 = OC5 RA15 is mapped to OC4 RPA15R = 0x0B;// 1011 = OC4 OC5 and OC4 are properly configured, together with associated Timer 3 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 36 of 56 Basys MX3TM Board Reference Manual Configuration functions are implemented for each servo. These functions configure OC5RS or OC4RS according to the desired duty. If users want to control the servos without the SRV library, they must implement their own servo control functionality. 15.3 Shared Pins As you can see from the schematic, the S0_PWM signal shares the same PIC32 pin with BTNR and the S1_PWM signals shares the same PIC32 pin with BTND (see User Buttons). These buttons should not be used in designs that are also using servos. 16 IrDA Module Basys MX3 features an onboard FIR-compatible IrDA module. The part used is the ROHM Semiconductor RPM973H11. The RPM973-H11 is a high-performance IrDA module that integrates an infrared remote control transmission function and a high-speed (4Mbps) FIR-compatible IrDA module. It features an LED for transmitting and a PIN photo diode for receiving. Figure 16.1. IrDA schematic diagram. The PIC32 communicates with the IrDA module via two pins (named from PIC32 perspective): IR_TX, connected to the TXD pin of the RPM973 and used for transmitting over IRDA, and IR_RX, connected to the RXD pin of the RPM973 and used for receiving data over IrDA. Also, an IR_PDOWN signal, connected to the PWDOWN pin of the RPM973, is used by the microcontroller to enable (0 value) or disable (1 value) the module. When TXD (IR_TX) is 1, the transmitting LED of the RPM973 module is lit. When the PIN photo diode detects light, it outputs 1 on RXD (IR_RX). 16.1 Connectivity The following table shows the signals connecting the IRDA module to the PIC32: Name IRDA_PDOWN PIC32 pin RPG1/PMD9/RG1 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. IRDA module pin PWDOWN/Mode Page 37 of 56 Basys MX3TM Board Reference Manual Name IR_TX IR_RX PIC32 pin PGED2/AN7/RPB7/CTED3/RB7 PGEC2/AN6/RPB6/RB6 IRDA module pin TXD RXD Table 16.1. IrDA connectivity. The IRDA_PDOWN and IR_TX must be defined as digital outputs and disable the analog functionality on IR_TX: TRISGbits.TRISG1 = 0; //set RG1 (IRDA_PDOWN) as an output TRISBbits.TRISB7 = 0; //set RB7 (IR_TX) as an output ANSELBbits.ANSB7 = 0; //disable analog functionality on RB7 (IR_TX) The IR_RX must be defined as digital input and the analog functionality disabled: TRISBbits.TRISB6 = 1; //set RB6 (IR_RX) as an input ANSELBbits.ANSB6 = 0; //disable analog functionality on RB6 (IR_RX) 16.2 Functionality The control of the IrDA module is implemented in the IrDA library of the Basys MX3 library pack. Library features include: IRDA_PDOWN is used as a basic digital output pin. IRDA communication signals are mapped over the UART5 communication signals: o U5RXR = 0x05; // IR_RX (RB6) -> U5RX o RPB7R = 0x04; // IR_TX (RB7) -> U5TX UART5 interface is configured in the IrDA mode (the IREN bit is set) with 9600 baud and used for sending and receiving data to IrDA module. If the users want to use the IrDA module without the IrDA library, they need to implement their own IrDA functionality. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 38 of 56 Basys MX3TM Board Reference Manual 17 Audio Out Figure 17.1. Audio out schematic diagram. The Basys MX3 contains an audio out module, controlled by the PIC32 using the digital signal A_OUT. This digital signal is PWM controlled to generate multiple values between 0 and 3.3V. A PWM signal is a chain of pulses generated at fixed frequency, with each pulse potentially having a different width. This digital signal can be passed through a simple low-pass filter that integrates the digital waveform to produce an analog voltage proportional to the average pulse-width over some interval (the interval is determined by the cut-off frequency of the low-pass filter and the pulse frequency). For example, if the pulses are high for an average of 10% of the available pulse period, then an integrator will produce an analog value that is 10% of the Vdd voltage, in this case .33V. Figure 17.2 shows a waveform represented as a PWM signal. Pulse Width Digital Signal Analog Signal (PWMA) Vdd Gnd Pulse Window = 1 / Pulse Frequency (f) Figure 17.2. Waveform represented as a PWM signal. The volume of the output audio signal can be adjusted using a thumbwheel potentiometer labeled SPEAKER VOLUME, situated in the top left corner of the board. The generated audio out signal is outputted to an onboard speaker through a 1.2W audio power amplifier (IS31AP4991) and to an onboard headphones connector, labeled LINE OUT. When headphones are connected to the LINE OUT port, the onboard speaker is automatically muted. 17.2 Connectivity Table 17.1 shows the details about the A_OUT signal connecting the audio module to the PIC32. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 39 of 56 Basys MX3TM Board Reference Manual Name A_OUT PIC32 pin AN14/RPB14/CTED5/PMA1/RB14 Table 17.1. Audio out connectivity. The A_ OUT pin will be used as a digital output pin: The corresponding TRIS bit must be set to 0: TRISBbits.TRISB14 = 0; The corresponding ANSEL bit should be set to 0: ANSELBbits.ANSB14 = 0; 17.2 Functionality Functionality for access to the audio module is implemented in the AUDIO library of the Basys MX3 library pack. These are the features of the implementation: The RB14 is mapped to OC1 RPB14R = 0x0C; // OC1 OC1 is properly configured, together with associated Timer 3 Every time the timer 3 interrupt handler routine is called, the OC1RS register gets the value of the audio sample that needs to be represented using PWM. If the user wants to use the audio out module without the AUDIO library, they must implement their own audio functionality. 18 Microphone Figure 18.1. Microphone schematic diagram. The Basys MX3 provides a basic microphone module. It is based on the Knowles Acoustics SPA2410LR5H-B MEMs microphone that has a high signal-to-noise ratio (SNR) of 94 dB SPL at 1 kHz. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 40 of 56 Basys MX3TM Board Reference Manual Figure 18.2. Microphone frequency response. The output of the microphone module is an analog signal A_MIC, connected to an analog input pin of PIC32. This analog pin must be sampled using the PIC32's ADC functionality to get a digital value. The PIC32 provides 10-bit data ADC sampling. Read more on the PIC32's ADC functionality in the Analog-To-Digital Converter (ADC) section of the PIC32 documentation. The microphone on the Basys MX3 also features adjustable gain that is controlled using a thumbwheel potentiometer labeled MIC VOLUME. This dial directly controls the gain of the A_MIC signal going into the PIC32. 18.1 Connectivity Table 18.1 below shows the details about the A_MIC signal connecting the microphone module to the PIC32. Name A_MIC PIC32 pin AN4/C1INB/RB4 SPA2410LR5H-B pin OUT Table 18.1. Microphone connectivity. The A_MIC pin will be used as analog input pin: The corresponding TRIS bit must be set to 1: TRISBbits.TRISB4 = 1; The corresponding ANSEL bit should be set to 1: ANSELBbits.ANSB4 = 1; 18.2 Functionality The microphone usage is described through library functions in the MIC and ADC libraries of the Basys MX3 library pack. Implementation features include: Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 41 of 56 Basys MX3TM Board Reference Manual The ADC module is initialized. Channel 4 is read (corresponding to AN4). If the user wants to acquire data from microphone module without the MIC and ADC libraries, they must implement their own ADC functionality. 19 Analog Input Control Figure 19.1. Analog input control schematic diagram. The Basys MX3 provides a basic analog input module. This module exposes an analog input signal called AIC to the PIC32. The user can provide an analog value between 0 and 3.3V using a thumbwheel potentiometer labeled ANALOG INPUT CONTROL. A pair of wire loops on the Basys MX3, labeled AIC and GND (J8 and J14 on the schematics), can be used to measure the voltage across the potentiometer using an external tool like a multimeter or oscilloscope. The AIC analog signal must be sampled using the PIC32's ADC functionality to get a digital value. The PIC32 provides 10-bit data ADC sampling. Read more on the PIC32's ADC functionality in the Analog-To-Digital Converter (ADC) section of the PIC32 documentation. 19.1 Connectivity Table 19.1 shows the details about the AIC signal connecting the analog input module to the PIC32. Name AIC PIC32 pin PGEC3/AN2/C2INB/RPB2/CTED13/RB2 Figure 19.1. Analog input control connectivity. The AIC pin will be used as an analog input pin: The corresponding TRIS bit must be set to 1: TRISBbits.TRISB2 = 1; The corresponding ANSEL bit should be set to 1: ANSELBbits.ANSB2 = 1; Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 42 of 56 Basys MX3TM Board Reference Manual 19.2 Functionality The Analog Input module is implemented in the ADC library of the Basys MX3 library pack. Implementation features include: The ADC module is properly initialized. Channel 2 is read (corresponding to AN2). If the users want to acquire data using the Analog Input module without the ADC library, they need to implement their own ADC functionality. 20 Pmod Connectors The Basys MX3 provides two host connectors for Digilent Pmods. The Pmod connectors, labeled PMOD A and PMOD B, are 2x6 right-angle, female pin header connectors. The schematic diagram in Fig. 20.1 depicts the signals routed to the two connectors. Figure 20.1. Pmod schematic diagram. The pin numbering that Digilent uses on the twelve-pin Pmod connectors may not seem typical. In the upper row the pins are numbered 1-6, left to right (when viewed from the top, middle of the board), and the pins in the lower row are numbered 7-12, left to right. This complies with the convention that the upper and lower rows of pins can be considered as two stacked six-pin connectors. When viewed from the end of the connector, pin 1 is the upper right pin and pin 7 is immediately below. Pin 1 is labeled on the Basys MX3 board with "1" and can be recognized by its squared pad (both on the main board and on the Pmod device). Each row of pins provides a pair of VCC (3.3V) and GND, as shown Fig. 20.2. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 43 of 56 Basys MX3TM Board Reference Manual VCC GND 8 signals Pin 1 Pin 6 Pin 12 Figure 20.2. Pmod connectors: front view, as loaded on PCB. Table 20.1 summarizes the content of PMODA connector. Pmod pin PMODA_1 PMODA_2 PMODA_3 PMODA_4 PMODA_7 PMODA_8 PMODA_9 PMODA_10 Schematic Label JA1 JA2 JA3 JA4 JA7 JA8 JA9 JA10 PIC32 pin RPC2/RC2 RPC1/RC1 RPC4/CTED7/RC4 AN16/C1IND/RPG6/SCK2/PMA5/RG6 RPC3/RC3 AN17/C1INC/RPG7/PMA4/RG7 AN18/C2IND/RPG8/PMA3/RG8 AN19/C2INC/RPG9/PMA2/RG9 Table 20.1. Pmod A pinout. Table 20.2 summarizes the content of PMODB connector. Pmod pin PMODB_1 PMODB_2 PMODB_3 PMODB_4 PMODB_7 PMODB_8 PMODB_9 PMODB_10 Schematic Label JB1 JB2 JB3 JB4 JB7 JB8 JB9 JB10 PIC32 pin RPD9/RD9 RPD11/PMCS1/RD11 RPD10/PMCS2/RD10 RPD8/RTCC/RD8 SOSCO/RPC14/T1CK/RC14 RPD0/RD0 AN24/RPD1/RD1 SOSCI/RPC13/RC13 Table 20.2. Pmod B pinout. The signals going to Pmod connectors are also connected to input/output pins on the PIC32 microcontroller. Review Section 1.3 Digital Inputs and Outputs for more details regarding digital I/Os. Instead of using the Pmod pins as regular digital input/output pins, the pins can be mapped to several peripherals, as explained in Section 1.4 Remappable pins. For example, the SPI2 interface is implemented over the PMODA pins, as explained in Section 11.2 SPI2. In the above tables, the highlighted pins are 5V tolerant pins. It is safe to apply 5V logic signals directly to these pins without risk of damage to the microcontroller. All other pins support 3.3V only. Each pin has a 200-ohm series resistor and an ESD protection diode. The series resistor provides short circuit protection to prevent damaging the I/O block in the microcontroller if the pin is inadvertently shorted to VDD or GND, or two outputs are shorted together. The ESD protection diode protects the I/O block from damage due to electro-static discharge. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 44 of 56 Basys MX3TM Board Reference Manual Although ESD protection is provided between the connector pins and the microcontroller pins, ESD safe handling procedures should be followed when handling the circuit board. The pins on the microcontroller and other circuits on the board are exposed and can be damaged through ESD when handling the board. Digilent Pmods can either be plugged directly into the connectors on the Basys MX3 or attached via cables. Digilent has a variety of Pmod cables available. You can read more details about the Digilent Pmod Interface Specification from the most recent specification document, available on the Digilent Pmod Wiki. 21 Analog Discovery Debug Header The Basys MX3 board provides a 2x15 Debug Header, exposing some pins that allow key onboard peripheral signals to be visualized with an oscilloscope or logic analyzer. Figure 21.1. Debug header schematic diagram. The connector is designed to match the Analog Discovery and OpenScope connectors, but the pins can be used with other tools as well. Table 21.1 below shows the signals exposed by this connector. Pin # 1 2 3 4 5 6 7 8 9 10 Silk Screen Name SPI_SI BIN2 SPI_CE BIN1 SPI_SO AIN2 SPI_SCK AIN1 D_RS IRRX Type Connected to / Module Analog Discovery pin RPF2/RF2 AN5/C1INA/RPB5/RB5 RPF8/RF8 RPE9/RE9 RPF7/RF7 RPE8/RE8 RPF6/SCK1/INT0/RF6 PGED3/AN3/C2INA/RPB3/RB3 AN15/RPB15/PMA0/CTED6/RB15 PGEC2/AN6/RPB6/RB6 SPI_SI / Flash memory BIN2 / Motor driver SPI_CE / Flash memory BIN1 / Motor driver SPI_SO / Flash memory AIN2 / Motor driver SPI_SCK / Flash memory AIN1 / Motor driver DISP_RS / LCD module IR_RX / IrDA module Digital IO 7 Digital IO 15 Digital IO 6 Digital IO 14 Digital IO 5 Digital IO 13 Digital IO 4 Digital IO 12 Digital IO 3 Digital IO 11 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 45 of 56 Basys MX3TM Board Reference Manual 11 12 13 14 15 16 Silk Screen Name DISP_R/W IRTX D_EN URX DB0 UTX 17 T1 RPF0/PMD11/RF0 18 T2 AN9/RPB9/CTED4/RB9 19 20 25 26 27 28 29 30 GND GND GND GND AOP AON AMIC GND GND GND GND GND analog pin analog pin AN4/C1INB/RB4 GND Pin # Type Connected to / Module Analog Discovery pin RPD5/PMRD/RD5 PGED2/AN7/RPB7/CTED3/RB7 RPD4/PMWR/RD4 RPF13/RF13 PMD0/RE0 RPF12/RF12 DISP_R/W / LCD module IR_TX / IrDA module DISP_EN / LCD module UART_RX / UART DB0 / LCD module UART_TX / UART BTNC / TRIG_1 / User Buttons SW7 / TRIG_2 / User Switches Digital IO 2 Digital IO 10 Digital IO 1 Digital IO 9 Digital IO 0 Digital IO 8 A_OUT_P / Audio out A_OUT_N / Audio out A_MIC / Microphone T1 T2 GND GND GND GND Scope 2+ Scope 2Scope 1+ Scope 1- Table 20.1. Debug header pinout. Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 46 of 56 Basys MX3TM Board Reference Manual Appendix 1: Remappable Input Pins Peripheral Pin [pin name]R SFR [pin name]R bits INT3 INT3R INT3R<3:0> T2CK T2CKR T2CKR<3:0> IC3 IC3R IC3R<3:0> U1RX U1RXR U1RXR<3:0> U2RX U2RXR U2RXR<3:0> U5CTS U5CTSR U5CTSR<3:0> REFCLKI REFCLKIR REFCLKIR<3:0> Peripheral Pin [pin name]R SFR [pin name]R bits INT4 INT4R INT4R<3:0> [pin name]R Value to RPn Pin Selection 0000 = RPD2 0001 = RPG8 0010 = RPF4 0011 = RPD10 0100 = RPF1 0101 = RPB9 0110 = RPB10 0111 = RPC14 1000 = RPB5 1001 = Reserved 1010 = RPC1 1011 = RPD14 1100 = RPG1 1101 = RPA14 1110 = Reserved 1111 = RPF2 [pin name]R Value to RPn Pin Selection 0000 = RPD3 0001 = RPG7 0010 = RPF5 0011 = RPD11 0100 = RPF0 0101 = RPB1 0110 = RPE5 0111 = RPC13 1000 = RPB3 1001 = Reserved 1010 = RPC4 1011 = RPD15 1100 = RPG0 1101 = RPA15 1110 = RPF2 1111 = RPF7 T5CK T5CKR T5CKR<3:0> IC4 IC4R IC4R<3:0> U3RX U3RXR U3RXR<3:0> U4CTS U4CTSR U4CTSR<3:0> SDI1 SDI1R SDI1R<3:0> SDI2 SDI2R SDI2R<3:0> Peripheral Pin [pin name]R SFR [pin name]R bits [pin name]R Value to RPn Pin Selection INT2 INT2R INT2R<3:0> 0000 = RPD9 0001 = RPG6 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 47 of 56 Basys MX3TM Board Reference Manual T4CK T4CKR T4CKR<3:0> IC2 IC2R IC2R<3:0> IC5 IC5R IC5R<3:0> U1CTS U1CTSR U1CTSR<3:0> U2CTS U2CTSR U2CTSR<3:0> SS1 SS1R SS1R<3:0> Peripheral Pin [pin name]R SFR [pin name]R bits INT1 INT1R INT1R<3:0> T3CK T3CKR T3CKR<3:0> IC1 IC1R IC1R<3:0> U3CTS U3CTSR U3CTSR<3:0> U4RX U4RXR U4RXR<3:0> U5RX U5RXR U5RXR<3:0> SS2 SS2R SS2R<3:0> OCFA OCFAR OCFAR<3:0> 0010 = RPB8 0011 = RPB15 0100 = RPD4 0101 = RPB0 0110 = RPE3 0111 = RPB7 1000 = Reserved 1001 = RPF12 1010 = RPD12 1011 = RPF8 1100 = RPC3 1101 = RPE9 1110 = Reserved 1111 = RPB2 [pin name]R Value to RPn Pin Selection 0000 = RPD1 0001 = RPG9 0010 = RPB14 0011 = RPD0 0100 = RPD8 0101 = RPB6 0110 = RPD5 0111 = RPB2 1000 = RPF3 1001 = RPF13 1010 = Reserved 1011 = RPF2 1100 = RPC2 1101 = RPE8 1110 = Reserved 1111 = Reserved Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 48 of 56 Basys MX3TM Board Reference Manual Appendix 2: Remappable Output Pins RPn Port Pin RPnR SFR RPD2 RPD2R RPG8 RPG8R RPF4 RPF4R RPD10 RPD10R RPF1 RPF1R RPB9 RPB9R RPB10 RPB10R RPC14 RPC14R RPB5 RPB5R RPC1 RPC1R RPD14 RPD14R RPG1 RPG1R RPA14 RPA14R RPn Port Pin RPnR SFR RPD3 RPD3R RPG7 RPG7R RPF5 RPF5R RPnR Value to Peripheral Selection 0000 = No Connect 0001 = U3TX 0010 = U4RTS 0011 = Reserved 0100 = Reserved 0101 = Reserved 0110 = SDO2 0111 = Reserved 1000 = Reserved 1001 = Reserved 1010 = Reserved 1011 = OC3 1100 = Reserved 1101 = C2OUT 1110 = Reserved 1111 = Reserved RPnR Value to Peripheral Selection 0000 = No Connect 0001 = U2TX 0010 = Reserved 0011 = U1TX 0100 = U5RTS 0101 = Reserved 0110 = SDO2 0111 = Reserved Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 49 of 56 Basys MX3TM Board Reference Manual RPD11 RPD11R RPF0 RPF0R RPB1 RPB1R RPE5 RPE5R RPC13 RPC13R RPB3 RPB3R RPF3 RPF3R RPC4 RPC4R RPD15 RPD15R RPG0 RPG0R RPA15 RPA15R RPn Port Pin RPnR SFR RPD9 RPD9R RPG6 RPG6R RPB8 RPB8R RPB15 RPB15R RPD4 RPD4R RPB0 RPB0R RPE3 RPE3R 1000 = SDO1 1001 = Reserved 1010 = Reserved 1011 = OC4 1100 = Reserved 1101 = Reserved 1110 = Reserved 1111 = Reserved RPnR Value to Peripheral Selection 0000 = No Connect 0001 = U3RTS 0010 = U4TX 0011 = REFCLKO 0100 = U5TX 0101 = Reserved 0110 = Reserved 0111 = SS1 1000 = SDO1 1001 = Reserved 1010 = Reserved 1011 = OC5 1100 = Reserved 1101 = C1OUT 1110 = Reserved 1111 = Reserved Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 50 of 56 Basys MX3TM Board Reference Manual RPB7 RPB7R RPB2 RPB2R RPF12 RPF12R RPD12 RPD12R RPF8 RPF8R RPC3 RPC3R RPE9 RPE9R RPD9 RPD9R RPn Port Pin RPnR SFR RPD1 RPD1R RPG9 RPG9R RPB14 RPB14R RPD0 RPD0R RPD8 RPD8R RPB6 RPB6R RPD5 RPD5R RPF3 RPF3R RPF6 RPF6R RPF13 RPF13R RPnR Value to Peripheral Selection 0000 = No Connect 0001 = U2RTS 0010 = Reserved 0011 = U1RTS 0100 = U5TX 0101 = Reserved 0110 = SS2 0111 = Reserved 1000 = SDO1 1001 = Reserved 1010 = Reserved 1011 = OC2 1100 = OC1 1101 = Reserved 1110 = Reserved 1111 = Reserved" Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 51 of 56 Basys MX3TM Board Reference Manual RPC2 RPC2R RPE8 RPE8R RPF2 RPF2R Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. Page 52 of 56 Basys MX3TM Board Reference Manual Appendix 3: Basys MX3 Pinout The following table details the Basys MX3 pinout, showing the following information: Pin #, Full Pin Name: The number and the name of the microcontroller pin, as in the microcontroller datasheet pin. Peripheral: The Basys MX3 peripheral that uses this pin. Schematic Name: the name of the pin in the schematic. PPS: The PPS remapping function of this pin. Function: The available function(s) of this pin. Pin # Full Pin Name Peripheral Schematic Name 1 RG15 SSD CE 2 VDD POWER VCC3V3 3 AN22/RPE5/PMD5/RE5 LCD DB5 4 AN23/PMD6/RE6 LCD DB6 PMD6 5 AN27/PMD7/RE7 LCD DB7 PMD7 6 RPC1/RC1 PMOD JA2 I/O 7 RPC2/RC2 PMOD JA1 I/O 8 RPC3/RC3 PMOD JA7 I/O 9 RPC4/CTED7/RC4 PMOD JA3 I/O SDI2/U3RX/IC4/T5CK/INT4/OC4 PMOD JA4 I/O SCK2/U3RTS/IC2/IC5/T4CK/INT2/O C5 PMOD JA8 I/O INT4/U1TX/U2TX/IC4/T5CK/OC4 PMOD JA9 I/O IC3/T2CK/INT3/U1RX/U2RX/OC3 I/O IC1/T3CK/INT1/U1RTS/U2RTS/OC1 /OC2 10 11 12 AN16/C1IND/RPG6/SCK2/ PMA5/RG6 AN17/C1INC/RPG7/PMA4 /RG7 AN18/C2IND/RPG8/PMA3 /RG8 PPS Function RG15 I/O PMD5 SDO2/U3TX/IC3/T2CK/INT3/OC3 SS2/U3CTS/IC1/T3CK/INT1/OC1/O C2 INT2/U1CTS/U2CTS/IC2/IC5/T4CK/ OC5 13 MCLR PROGRAM/ DEBUG PIC32_MCL R 14 AN19/C2INC/RPG9/PMA2 /RG9 PMOD JA10 15 VSS POWER GND 16 VDD POWER VCC3V3 17 TMS/CTED1/RA0 LEDS LED0 18 RPE8/RE8 MOTOR AIN2 I/O OC2/RE8 19 RPE9/RE9 MOTOR BIN1 I/O OC5/RE9 20 AN5/C1INA/RPB5/RB5 MOTOR BIN2 I/O OC3/RB5 21 AN4/C1INB/RB4 MICROPHO NE A_MIC MOTOR AIN1 I/O OC4/RB3 POTENTIOM ETER AIC I/O AN2/C2INB 22 23 PGED3/AN3/C2INA/RPB3/ RB3 PGEC3/AN2/C2INB/RPB2/ CTED13/RB2 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. RA0 AN4/C1INB Page 53 of 56 Basys MX3TM Board Reference Manual Schematic Name PPS Function P32_PGC/B TNU I/O RB1 P32_PGD/B TNL I/O RB0 IRDA IR_RX I/O U5RX PGED2/AN7/RPB7/CTED3/ RB7 IRDA IR_TX I/O URTX 28 VREF-/CVREF-/PMA7/RA9 SSD AN2 RA9 29 VREF+/CVREF+/PMA6/RA1 0 SSD AN3 RA10 30 AVDD POWER VCC3V3 31 AVSS POWER GND 32 AN8/RPB8/CTED10/RB8 BUTTONS BTNR/S0_P WM I/O RB8/OC5 33 AN9/RPB9/CTED4/RB9 SWITCHES SW7 I/O RB9 34 CVREFOUT/AN10/RPB10/ CTED11/PMA13/RB10 SWITCHES SW6 I/O RB10 35 AN11/PMA12/RB11 SWITCHES SW5 36 VSS POWER GND 37 VDD POWER VCC3V3 38 TCK/CTED2/RA1 LEDS LED1 39 RPF13/RF13 FTDI UART_RX I/O U4RX 40 RPF12/RF12 FTDI UART_TX I/O U4TX 41 AN12/PMA11/RB12 SSD AN0 RB12 42 AN13/PMA10/RB13 SSD AN1 RB13 AUDIO_OUT A_OUT I/O OC1 LCD DISP_RS I/O PMA0 Pin # Full Pin Name 24 PGEC1/AN1/RPB1/CTED12 /RB1 25 PGED1/AN0/RPB0/RB0 26 PGEC2/AN6/RPB6/RB6 27 43 44 AN14/RPB14/CTED5/PMA 1/RB14 AN15/RPB15/OCFB/CTED6 /PMA0/RB15 Peripheral PROGRAM/ DEBUG/ BUTTONS PROGRAM/ DEBUG/ BUTTONS RB11 RA1 45 VSS POWER GND 46 VDD POWER VCC3V3 47 RPD14/RD14 SWITCHES SW4 I/O RD14 48 RPD15/RD15 SWITCHES SW3 I/O RD15 49 RPF4/PMA9/RF4 SWITCHES SW2 I/O RF4 50 RPF5/PMA8/RF5 SWITCHES SW1 I/O RF5 51 RPF3/RF3 SWITCHES SW0 I/O RF3 52 RPF2/RF2 SPI_FLASH SPI_SI I/O 53 RPF8/RF8 SPI_FLASH SPI_CE I/O 54 RPF7/RF7 SPI_FLASH SPI_SO I Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. SDO1/U5TX/U4RX/U5RX/IC1/T3CK /INT1OC1/OC2 SS1/U1CTS/U2CTS/IC2/IC5/T4CK/I NT4/OC5 SDI1/U3RX/IC4/T5CK/INT4 Page 54 of 56 Basys MX3TM Board Reference Manual Pin # Full Pin Name Peripheral Schematic Name PPS Function 55 RPF6/SCK1/INT0/RF6 SPI_FLASH SPI_SCK I/O SCK1/U1RTS/U2RTS/OC1/OC2/INT 0 56 SDA1/RG3 I2C SDA SDA1 57 SCL1/RG2 I2C SCL SCL1 58 SCL2/RA2 LEDS LED2 RA2 59 SDA2/RA3 LEDS LED3 RA3 60 TDI/CTED9/RA4 LEDS LED4 RA4 61 TDO/RA5 LEDS LED5 RA5 62 VDD POWER VCC3V3 63 OSC1/CLKI/RC12 CLOCK 8MHZ CRYSTAL 64 OSC2/CLKO/RC15 CLOCK 8MHZ CRYSTAL 65 VSS POWER GND 66 RPA14/RA14 SSD CB I/O RA14 67 RPA15/RA15 BUTTONS BTND/S1_P WM I/O RA15/OC4 68 RPD8/RTCC/RD8 PMOD JB4 I/O 69 RPD9/RD9 PMOD JB1 I/O 70 RPD10/PMCS2/RD10 PMOD JB3 I/O U1RX/U2RX/IC3/T2CK/INT3/OC3 71 RPD11/PMCS1/RD11 PMOD JB2 I/O U1TX/U2TX/IC4/T5CK/INT4/OC4 72 RPD0/RD0 PMOD JB8 I/O INT1/U5TX/IC1/T3CK/OC1/OC2 73 SOSCI/RPC13/RC13 PMOD JB10 I/O INT4/U5RTS/IC4/T5CK/OC4 74 SOSCO/RPC14/T1CK/RC14 PMOD JB7 I/O INT3/U5CTS/IC3/T2CK/OC3 75 VSS POWER GND 76 AN24/RPD1/RD1 PMOD JB9 I/O INT1/U5RX/IC1/T3CK/OC1/OC2 77 AN25/RPD2/RD2 RGB_LED LED8_R I/O OC3/RD2 78 AN26/RPD3/RD3 RGB_LED LED8_B I/O OC4/RD3 79 RPD12/PMD12/RD12 RGB_LED LED8_G I/O OC5/RD12 80 PMD13/RD13 SSD CG 81 RPD4/PMWR/RD4 LCD DISP_EN I/O PMENB 82 RPD5/PMRD/RD5 LCD DISP_R/W I/O PMRD/PMWR 83 PMD14/RD6 SSD CC RD6 84 PMD15/RD7 SSD CF RD7 85 VCAP POWER CAPACITOR 86 VDD POWER VCC3V3 87 RPF0/PMD11/RF0 BUTTONS BTNC I/O RF0 88 RPF1/PMD10/RF1 MOTOR MODE I/O RF1 89 RPG1/PMD9/RG1 IRDA IR_PDOWN I/O RG1 90 RPG0/PMD8/RG0 ACCELEROM ETER ACL_INT2 I/O INT4 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. U1RTS/U2RTS/IC1/T3CK/INT1/OC1 /OC2 U1CTS/U2CTS/IC2/IC5/T4CK/INT2/ OC5 RD13 Page 55 of 56 Basys MX3TM Board Reference Manual Pin # Full Pin Name Peripheral Schematic Name 91 TRCLK/RA6 LEDS LED6 RA6 92 TRD3/CTED8/RA7 LEDS LED7 RA7 93 PMD0/RE0 LCD DB0 PMD0 94 PMD1/RE1 LCD DB1 PMD1 95 TRD2/RG14 SSD DP RG14 96 TRD1/RG12 SSD CA RG12 97 TRD0/RG13 SSD CD RG13 98 AN20/PMD2/RE2 LCD DB2 PMD2 99 RPE3/CTPLS/PMD3/RE3 LCD DB3 100 AN21/PMD4/RE4 LCD DB4 Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners. PPS I/O Function PMD3 PMD4 Page 56 of 56