Digilent 32MX7 User Manual

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Cerebot 32MX7 Circuit Diagram

Revision: October 20, 2011 Note: This document applies to REV C of the board.

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Overview

The Cerebot 32MX7 board is a useful tool for embedded control and network communications projects for both students and hobbyists.

Its versatile design and programmable microcontroller lets you access numerous peripheral devices and program the board for multiple uses. The board has many I/O connectors and power supply options. It’s network and communications features include 10/100 Ethernet interface, Full Speed USB 2.0 OTG interface, dual CAN network interfaces, dual I2C buses, up to three UART ports and up to three SPI ports.

The Cerebot 32MX7 works with the Microchip MPLAB development environment and provides built in programming and debugging support within MPLAB.

The Cerebot 32MX7 provides a number of connections for peripheral devices. It has six connectors for attaching Digilent Pmod™ peripheral modules. Digilent Pmod peripheral modules include H-bridges, analog-to-digital and digital-to-analog converters, a speaker amplifier, switches, buttons, LEDs, as well as converters for easy connection to RS232, screw terminals, BNC jacks, servo motors, and more.

Features include:

• a PIC32MX795F512L microcontroller

• support for programming and

debugging within the Microchip MPLAB development environment

• six Pmod connectors for Digilent peripheral module boards

• 10/100 Ethernet

• USB 2.0 Device, Host, and OTG

support

• two CAN network interfaces

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• three push buttons

• four LEDs

• multiple power supply options, including

USB powered

• ESD protection and short circuit protection for all I/O pins.

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Cerebot 32MX7 Reference Manual

Features of the PIC32MX795F512L include:

• 512KB internal program flash memory

• 128KB internal SRAM memory

• USB 2.0 compliant full-speed On-The-

Go (OTG) controller with dedicated DMA channel

• 10/100 Ethernet controller

• two CAN network controllers

• up to four serial peripheral interfaces

(SPI)

• up to six UART serial interfaces

• up to four I2C serial interfaces

• five 16-bit timer/counters

• five timer capture inputs

• five compare/PWM outputs

• sixteen 10-bit analog inputs

• two analog comparators

For more information on the PIC32MX795F512L microcontroller, refer to the PIC32MX5XX/6XX/7XX Family Data Sheet and the PIC32 Family Reference Manual available at www.microchip.com.

Functional Description

The Cerebot 32MX7 is designed for embedded control and network communications applications as well as general microprocessor experimentation. Firmware suitable for many applications can be downloaded to the Cerebot 32MX7’s programmable PIC32 microcontroller.

The board has a number of input/output connection options, and is specially designed to work with the Digilent line of Pmod peripheral modules with various input and output functions. For more information, see

www.digilentinc.com. In addition to the Pmod

connectors, the board provides three push buttons and four LEDs for user i/o, as well as providing connections for two I2C busses. A serial EEPROM is provided on one of the I2C busses.

The Cerebot 32MX7 can be used with the Microchip MPLAB development environment. In-system-programming and debug of firmware

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running on the PIC32MX795 microcontroller is supported using an on-board program/debug circuit licensed from Microchip.

The Cerebot 32MX7 features a flexible power supply system with a number of options for powering the board as well as powering peripheral devices connected to the board. It can be USB powered via either the debug USB port or the USB device port, or it can be powered from an external power supply or batteries.

Programming and In-System Debugging Using the MPLAB® IDE

The Cerebot 32MX7 board is intended to be used with the Microchip MPLAB® IDE for firmware development, programming and insystem debugging using a circuit licensed from Microchip. MPLAB version 8.63 or later is required for use of the on-board program/debug circuit. The licensed debugger is accessed via USB, using connector J15. This connector is a micro-USB connector on the lower left side of the board, near the power switch. The provided USB cable should be connected from J15 to a USB port on the development PC for access to the board.

When creating a new project, use the Configure.Select Device menu to specify the PIC32 device in use. Ensure that the device is set to PIC32MX795F512L.

To use the on-board program/debug circuit it must be selected as the debugger or programmer within the MPLAB IDE. Use the

Debugger.Select Tool menu, or the Programmer.Select Tool menu, and select “Licensed Debugger” as the programmer or

debugger.

The in-system programming/debugging interface uses two pins on the PIC32 microcontroller. The PIC32 devices support two alternate pin pairs for this interface: PGC1/PGD1 or PGC2/PGD2. PIC32 devices use PGC2/PGD2 by default. Due to conflicting uses of the microcontroller pins, the Cerebot

Cerebot 32MX7 Reference Manual

32MX7 is designed to use PGC1/PGD1. Because of this, it is necessary to select the use of PGC1/PGD1 for the debugging interface. This is done using configuration variables set using the

#pragma config

statement. The following statement must be used to configure the microcontroller for use with the on-board licensed debugger circuit:

#pragma config ICESEL = ICS_PGx1

The MPLAB IDE may report an error indicating that the device is not configured for debugging until a program containing this statement has been programmed into the board.

Board Power Supply

Switch SW1, in the lower left corner of the board is the power switch. Place this switch in the ON position to turn on board power and in the OFF position to turn off board power.

There are three power options for main power to the board: USB powered from the debug USB connector, USB powered from the USB device connector, or external, non-USB powered. Jumper block J16, (above the Ethernet connector, J11) is used to select the main power source. To select USB powered from the debug connector, place the shorting block in the DBG position. To select USB power from the USB device connector, place the shorting block in the USB position. This option is used when the board is being used to implement a bus powered USB device. To power the board from an external power supply, place the shorting block in the EXT position. The board comes from the factor jumpered for USB power from the debug USB connector.

When powering the board from an external power supply, there are two power supply connectors that can be used: J17 and J18.

The barrel connector, J17, is used to power the board from a “wall wart” style power supply. This type of power supply is available from many sources. Digilent has an optional power

Supply, that can be used with connector J17. Connector J17 is a 2.5mm x 5.5mm coaxial connector wired with the center terminal as the positive voltage.

Connector J18 is a screw terminal connector for an alternative power supply connection for use with battery packs, bench supplies or other power sources where use of a hard wired power supply is desirable.

The Cerebot 32MX7 is rated for external power from 3.6 to 5.5 volts DC. Using a voltage outside this range will damage the board and connected devices. For most purposes, when using external power, a regulated 5V supply should be used. When operating the board from an external supply with a voltage less than 5V, some features of the board won’t work correctly.

When the Cerebot 32MX7 is operating as a USB host, an external power supply connected to either J17 or J18 must be used to power the board. In addition to powering the logic on the Cerebot 32MX7 board, this supply provides the USB bus voltage supplied to any connected USB device and must be a regulated 5V with at least 500mA current capability to meet the USB specifications.

The CAN bus operates at 5V, and therefore the transceivers for the two CAN interfaces require 5V to operate correctly and within the CAN specification. When using the CAN network interfaces, the board should be operated from a 5V supply if using an external power supply.

Connectors J17, and J18 are wired in parallel and connect to the “External Power” position (center position) on the Power Select jumper block J16. A shorting block should be placed on the “EXT” position of J16 when using this option for board power. Only one of the external power connectors should be used at a time. If multiple power supplies are connected simultaneously, damage to the board or the power supplies may occur.

supply available, the 5V Switching Power

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Cerebot 32MX7 Reference Manual

The power supply selected by the shorting block on J16 will appear on the input power supply bus, labeled VIN in the schematic. This voltage is regulated to 3.3V to power the debug circuit by IC11, a Microchip MCP1801 Low Dropout voltage regulator. This regulator is turned on and the debug circuit is powered whenever the power switch is in the on position.

The USB specification requires that USB devices not draw more than 100mA of current until they have enumerated on the USB bus and informed the host that they want to consume more current. To meet this specification, the debug circuit turns on main board power by driving the PWR_ON signal high after successfully enumerating on the USB bus. The bus labeled on the schematic as VCC5V0 is switched on when this occurs. The VCC5V0 bus powers the input to the main board voltage regulator, the input voltage to the USB bus voltage load switch used when using the board as a USB host, the power supply voltage for the CAN transceivers, and the 5V0 side of the power select jumpers for the Pmod connectors. The voltage on the VCC5V0 bus will be 5V when the board is being operated from USB power or an external regulated 5V supply. If a different external supply voltage is used, that voltage will appear on the VCC5V0 bus.

Note: The signal labeled DBG5V0 on the schematic comes from the debug USB connector. If the debug USB connector is not connected to a live USB port, this voltage will not be present and the debug circuit is not involved in turning on board power. In this case, the board power is turned on when the power switch is placed in the ON position.

The PIC32 microcontroller and on-board I/O devices operate at a supply voltage of 3.3V provided by the VCC3V3 bus. The regulated voltage on this bus is provided by a Microchip MCP1726 Low Dropout voltage regulator, IC10. This regulator is capable of providing a maximum of 1A of current. The PIC32 microcontroller will use approximately 85mA when running at 80MHz. The SMSC LAN8720

Ethernet PHY consumes approximately 45mA when operating at 100Mbps. The Microchip MCP2551 CAN transceivers can draw up to 75mA each when operating the CAN busses. The other circuitry on the board will draw 10-20 mA. The remaining current is available to provide power to attached Pmods and I2C devices. The voltage regulator is on the bottom of the board, approximately under the “3” in the Cerebot 32MX7 logo, and will get warm when the amount of current being used is close to its limit.

The Cerebot 32MX7 can provide power to any peripheral modules attached to the Pmod connectors, JA-JF, and to I2C devices powered from the I2C daisy chain connectors, J7 and J8. Each Pmod connector provides power pins that can be powered from either the switched main power bus, VCC5V0, or regulated voltage, VCC3V3, by setting the voltage jumper block to the desired position. The I2C power connectors only provide the regulated voltage, VCC3V3.

USB Interface

The PIC32MX795 microcontroller contains a USB 2.0 Compliant, Full Speed Device and On-The-Go (OTG) controller. This controller provides the following features:

• USB full speed host and device support

• Low speed host support

• USB OTG support

• Endpoint buffering anywhere in system

RAM

• Integrated DMA to access system RAM and Flash memory.

The USB controller uses a phased lock loop, PLL, to generate the necessary USB clock frequency from the external primary oscillator input frequency. By default, this PLL is disabled. In order to use the USB controller, it is necessary to enable the USB PLL, and set the input divider to the correct value to generate a valid USB clock. The input to the USB PLL must be 4Mhz. The Cerebot 32MX7 provides an 8Mhz clock to the PIC32

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Cerebot 32MX7 Reference Manual

microcontroller, so a USB PLL input divider value of 2 must be used. These parameters are set in the PIC32 microcontroller configuration registers using the

config

statement. The following statements

#pragma

must be used to configure the PIC32 microcontroller for use of the USB controller:

#pragma config UPLLEN = ON #pragma config UPLLIDIV = DIV_2

When operating as a USB device, the Cerebot 32MX7 can be used as a self powered device or as a bus powered device. To operate as a self powered device, an external power supply should be connected to one of the external power connectors (J17 or J18) and a shorting block placed on the center, “EXT” position of J16. The external power supply must be a regulated 5V supply. To operate as a bus powered device, the shorting block should be placed in the USB Device position, “USB”, on J16.

Connector J19, on the bottom of the board in the lower right corner is the Device/OTG connector. This is a standard USB micro-AB connector. Connect a cable with a micro-A plug (optionally available from Digilent) from this connector to an available USB port on a PC or USB hub for device operation.

When operating as a USB host, the Cerebot 32MX7 must be externally powered. Connect a regulated 5V power supply to one of the external power connectors (J17, or J18) and ensure that the shorting block is in the center, “EXT” position of J16. The power supply used must be a regulated 5V supply. The Cerebot 32MX7 board provides power to the attached USB device when operating as a host, and the USB specification requires the use of a 5V power supply. NOTE: Providing a voltage greater than 5V can damage the Cerebot 32MX7 board and/or the USB device being used.

Jumper JP10 is used to route power to the host connector being used. Place the shorting block in the “A” position when using the

Place the shorting block in the “MICRO” position for use with the USB micro-AB (OTG) connector, J19.

When operating as a USB host, the PIC32MX795 microcontroller controls application of power to the connected device via the VBUSON control pin (labeled P32_VBUSON in the schematic). Bus power is applied to the device by driving the VBUSON pin high. Power is removed from the device by driving the VBUSON pin low. The VBUSON pin is accessed via bit 3 of the U1OTGCON register.

The VBUSON pin drives the enable input of a TPS2051B Current-Limited Power Distribution Switch to control the application of USB power to the host connector. This switch has overcurrent detection capability and provides an over-current fault indication by pulling the signal P32_USBOC low. The over-current output pin can be monitored via the INT1/RE8 pin on the PIC32MX795 microcontroller. Details about the operation of the TPS2051B can be obtained from the data sheet available at the Texas Instruments web site.

There are reference designs available on the Microchip web site demonstrating both device and host operation of PIC32 microcontrollers. These reference designs are suitable to use for developing USB firmware for the Cerebot 32MX7 board.

Ethernet Interface

The Cerebot 32MX7 provides the ability to interface with 10Mbps or 100Mbps Ethernet networks. The PIC32MX795 microcontroller contains a 10/100 Ethernet Medium Access Controller (MAC). External to the microcontroller, the Cerebot 32MX7 board provides an SMSC LAN8720 Ethernet Physical Layer Transceiver (PHY). Together, the MAC and PHY in combination with an appropriate coupling transformer and RJ45 jack provide a standard 10/100 Ethernet interface.

standard USB type A (host) Connector, J20.

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Cerebot 32MX7 Reference Manual

The RJ45 connector J11, provides the physical connection to an Ethernet network using a standard Ethernet cable.

All devices on an Ethernet network must have a unique address. This address is used to direct packets on the network to a specific device and to identify the device that originated a packet. An Ethernet MAC uses a 48-bit address value, commonly called the “MAC Address”. These address values are globally unique to ensure that no two devices on a network can have conflicting addresses. MAC addresses are assigned by the IEEE. The address to use with the Cerebot 32MX7 is printed on a sticker attached to the bottom of the board. The address is a twelve digit hexadecimal number of the form: 00183Exxxxxx, where xxxxxx represents six hexadecimal digits. This value is used to initialize the Ethernet Controller MAC Station Address registers in the Ethernet controller of the PIC32MX795 microcontroller.

In order to connect to and operate with an Ethernet network, the PIC32 microcontroller must be running network protocol stack firmware. Normally, the TCP/IP (Transmission Control Protocol/Internet Protocol) network protocol is used and “TCP/IP Stack” software must be used. The Microchip Applications Library, available for download from the Microchip web site provides full protocol stack support compatible with the PIC32MX795 MAC and the LAN8720 PHY. Microchip also provides numerous example programs illustrating the use of their network protocol stack for various applications.

When not using the Microchip network protocol stack, refer to the manufacturer documentation for the PIC32MX795 and LAN8720, plus network protocol documentation, for operation of the Ethernet interface.

The PIC32MX795 microcontroller provides two alternate sets of pins that can be used to connect the MAC to the external PHY. It also provides two alternate standard MAC/PHY interface signaling conventions. The Cerebot

the alternate) pins, and to use the RMII (not the MII) interface signaling convention. These options are selected using the configuration variables in the PIC32 microcontroller and are specified using the

#pragma config

statement. To enable the Ethernet controller in the correct configuration, the following statements must appear in the main program module:

#pragma config FETHIO=ON #pragma config FMIIEN=OFF

The LAN8720 PHY has a reset signal, labeled NRST in the schematic, that can be used to reset the PHY. This signal is connected to the INT2/RE9 pin on the PIC32 microcontroller. The NRST signal is active low. Configure the microcontroller pin as an output and drive it low to reset the PHY, or drive it high to allow the PHY to come out of reset and begin operation. The NRST signal is pulled low on the board, so that the PHY is held in reset by default. To allow the PHY to operate, this pin must be driven high. This reset operation is not part of the Microchip network protocol stack, and so driving NRST high must be done before initializing the Microchip network stack.

CAN Interfaces

The Controller Area Network (CAN) standard is a control networking standard originally developed for use in automobile systems, but has since become a standard used in various industrial control and building automation networking applications as well.

The PIC32MX795 microcontroller contains two independent CAN network controllers. These CAN controllers in combination with two Microchip MCP2551 CAN transceivers allow the Cerebot 32MX7 board to operate on up to two independent CAN networks. Refer to the PIC32MX7XX data sheet and the PIC32 Family Reference Manual, plus CAN network documentation for information on operation of the CAN controllers and CAN networking in general.

32MX7 is designed to use the standard (not

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Cerebot 32MX7 Reference Manual

The PIC32MX795 microcontroller provides two sets of pins that can be used to connect the CAN controllers to the external transceivers. The Cerebot 32MX7 is designed to use the alternate (not the standard) pins. This selection is made using the configuration variables in the microcontroller, set using a

#pragma config

statement. To select the use of the alternate interface pins, the following statement must appear in the main program module:

enable/disable the termination resistor for the CAN1 network connector, and JP7 is used to enable/disable the termination resistor for CAN2. Install a shorting block on the jumper pins to enable the termination resistor, or remove the shorting block to disable the termination resistor.

I2C™ Interfaces

#pragma config FCANIO=OFF

The pins on the PIC32MX795 microcontroller used by signals for the CAN1 controller to connect to its transceiver are shared with two of the signals for UART3A and SPI port 3A. Jumpers JP1 and JP2 are used to select the use of these two signals. Place JP1 and JP2 in the CAN position for use of the CAN1 network interface. Place JP1 and JP2 in the PMOD position for use of these signals for UART or SPI operation. These signals connect to pins 1 & 4 of Pmod connector JF. When JP1 and JP2 are in the CAN position, Pins 1 & 4 of Pmod connector JF are not useable.

There is no standard connector for use with CAN networks. The Cerebot 32MX7 board provides two 2x6 pin header connectors for access to the CAN signals. Connector J9 provides access to the signals for the CAN1 network controller, and connector J10 provides access to the signals for CAN2. Refer to the schematic for the Cerebot 32MX7 board for information on the connectors and signals. Digilent 6-pin or 2x6 to dual 6-pin cables can be used to daisy chain Digilent boards together in a CAN network. A Digilent 6-Pin cable in combination with a Digilent PmodCON1 Screw Terminal Connector module can be used to connect the Cerebot 32MX7 board to other network wiring configurations.

The CAN network standard requires that the network nodes at each end of a network provide 120 ohm termination. The Cerebot 32MX7 provides the termination resistors and jumpers to enable/disable the termination resistors depending on the location of the board in the network. Jumper JP5 is used to

The Inter-Integrated Circuit (I2CTM) Interface provides a medium speed (100K or 400K bps) synchronous serial communications bus. The I2C interface provides master and slave operation using either 7 bit or 10 bit device addressing. Each device is given a unique address, and the protocol provides the ability to address packets to a specific device or to broadcast packets to all devices on the bus. Refer to the Microchip PIC32MX7XX Data Sheet and the PIC32 Family Reference Manual for detailed information on configuring and using the I2C interface.

The PIC32MX795 microcontroller provides for up to five independent I2C interfaces. The Cerebot 32MX7 is designed to provide dedicated access to two of these interfaces I2C #1 and I2C #2. There are two sets of connectors on the board for access to the two I2C ports. Connector J8 provides access to I2C #1 while connector J7 provides access to I2C #2.

Each I2C connector provides two positions 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 Cerebot 32MX7 boards or other I2C-capable boards can be created.

The I2C bus is an open-collector bus. Devices on the bus actively drive the signals low. The high state on 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 Cerebot 32MX7, I2C #1 has permanently connected pull-up resistors. I2C #2 provides selectable pull-up resistors that can be enabled or

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Cerebot 32MX7 Reference Manual

disabled via jumper blocks on the ‘pull-up’ positions on connector J2. The pull-ups are enabled by installing shorting blocks and are disabled by removing the shorting blocks. The shorting blocks are placed so that they line up with the SCL and SDA labels on the board. Only one device on the bus should have the pull-ups enabled.

The pull-up resistors on I2C #2 on the Cerebot 32MX7 board are actually implemented using current mirrors rather than simple resistors. These current mirrors source approximately

1.7mA. The use of current mirrors provides faster rise times on the I2C signals and provides the ability to drive longer cable runs reliably than would be the case with simple pull-up resistors.

I/O interfaces. The Pmod line includes such things as button, switch and LED modules, connector modules, LCD displays, high current output drivers, and many others.

There are two styles of Pmod connector: sixpin and twelve-pin. Both connectors use standard pin headers with 100mil spaced pins. The six-pin connectors have the pins in a 1x6 configuration, while the twelve-pin connectors use a 2x6 configuration. The six-pin connectors provide four I/O signals, ground and a switchable power connection. The twelve-pin connectors provide eight I/O signals, two power and two ground pins. The twelve-pin connectors have the signals arranged so that one twelve-pin connector is equivalent to two of the six-pin connectors. The power connection is switchable between the regulated 3.3V main board supply and the unregulated input supply.

Digilent Pmod peripheral modules can either be plugged directly into the connectors on the Cerebot 32MX7 or attached via cables.

3V3

SCL

SDA

GND

Pull-ups Enabled

Jumper Settings for I2C Pull-Up Resistors

On-Board I2C Peripheral Device

The Cerebot 32MX7 provides one on-board I2C peripheral device, a Microchip 24LC256 serial EEPROM. This device is connected to I2C #1. The 24LC256 is a 256Kbit (32Kbyte) serial EEPROM device to provide non-volatile memory storage. The device address for the 24LC256 is 1010000 (0x50).

Refer to the Microchip data sheet for detailed information on the operation of this device.

Pmod Connectors

The Cerebot 32MX7 has six Pmod connectors for connecting Digilent Pmod peripheral modules. Digilent Pmods are a line of small

SCL

SDA

Pull-ups Disabled

3V3

GND

Digilent has a variety of Pmod interconnect cables available.

See the “Connector and Jumper Block Pinout Tables” section below for more information about connecting peripheral modules and other devices to the Cerebot 32MX7. These tables indicate the mapping between pins on the PIC32MX795 microcontroller and the pins on the various connectors.

User I/O Devices

The Cerebot 32MX7 board provides three push button switches for user input and four LEDs for output. The buttons, BTN1 and BTN2 are connected to I/O pins RG6, RG7 and RD13 respectively. To read the buttons, bits 6 and 7 of PORTG and/or bit 13 of PORTD must be set as inputs by setting the corresponding bits in the TRISG and/or TRISD register and then reading the PORTG and/or PORTD register. When a button is pressed, the corresponding bit will be high (‘1’).

peripheral modules that provide various kind of

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Cerebot 32MX7 Reference Manual

The four LEDs are connected to bits 12-15 of PORTG. LED 1 is connected to bit 12, LED 2 is connected to bit 13, and so on. To use the LEDs, set the desired bits as outputs by clearing the corresponding bits in the TRISG register and set the bits to the desired value in the PORTG register. Setting a bit to 1 will illuminate the LED and setting the bit to 0 will turn it off.

CPU Clock Source

The PIC32 microcontroller supports numerous clock source options for the main processor operating clock. The Cerebot 32MX7 board is designed to support either a silicon resonator from Discera, IC2, for use with the EC oscillator option, or an external crystal for use with the XT oscillator option. Standard production boards will have an 8Mhz Discera silicon resonator loaded and the EC oscillator option should be used. If IC2 is not loaded, an 8Mhz crystal will be loaded for X1 (on the bottom of the board) and the XT oscillator option should be used. Oscillator options are selected via the configuration settings specified using the #pragma config statement. Use

#pragma config POSCMOD=EC

EC option and

#pragma config POSCMOD=XT

to select the XT option.

to select the

input divider, the multiplication factor and

FPLLODIV

#pragma config FPLLMUL

#pragma config

to set

to set the output divider. Refer to the PIC32MX5XX/6XX/7XX Family Data Sheet and the PIC32MX Family Reference Manual, Section 6. 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, and in particular is the clock used by the timers, and serial controllers (UART, SPI, I2C). The PBLCK frequency is a division of the SYSCLK frequency selected using

config FPBDIV

. The PBCLK divider can be

#pragma

set to divide by 1, 2, 4, or 8.

The following example will set up the Cerebot 32MX7 for operation with a SYSCLK frequency of 80Mhz and a PBCLK frequency of 10Mhz:

#pragma config FNOSC = PRIPLL #pragma config POSCMOD = EC #pragma config FPLLIDIV = DIV_2 #pragma config FPLLMUL = MUL_20 #pragma config FPLLODIV = DIV_1 #pragma config FPBDIV = DIV_8

Using the internal system clock phase-locked loop (PLL), it is possible to select numerous multiples or divisions of the 8Mhz oscillator to produce CPU operating frequencies up to 80Mhz. The clock circuit PLL provides an input divider, multiplier, and output divider. The external clock frequency (8Mhz) 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 operating frequency is selected using the PIC32MX795 configuration variables. These are set using the Use

#pragma config FPLLIDIV

#pragma config

statement.

to set the

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Cerebot 32MX7 Reference Manual

Appendix A: Example of Configuration Values

The following example illustrates setting the configuration values in the PIC32 microcontroller on the Cerebot 32MX7. The microcontroller configuration should be done in a single source file in the project, and is typically done in the ‘main’ project source file. This example sets all configuration values to valid values for the Cerebot 32MX7 board. It sets the system clock for processor operation at 80Mhz, and the peripheral bus at 10Mhz.

/* ------------------------------------------------------------ */ /* PIC32 Configuration Settings */ /* ------------------------------------------------------------ */

/* Oscillator Settings */ #pragma config FNOSC = PRIPLL // Oscillator selection #pragma config POSCMOD = EC // Primary oscillator mode #pragma config FPLLIDIV = DIV_2 // PLL input divider #pragma config FPLLMUL = MUL_20 // PLL multiplier #pragma config FPLLODIV = DIV_1 // PLL output divider #pragma config FPBDIV = DIV_8 // Peripheral bus clock divider #pragma config FSOSCEN = OFF // Secondary oscillator enable

/* Clock control settings */ #pragma config IESO = OFF // Internal/external clock switchover #pragma config FCKSM = CSDCMD // Clock switching (CSx)/Clock monitor (CMx) #pragma config OSCIOFNC = OFF // Clock output on OSCO pin enable

/* USB Settings */ #pragma config UPLLEN = ON // USB PLL enable #pragma config UPLLIDIV = DIV_2 // USB PLL input divider #pragma config FVBUSONIO = OFF // VBUS pin control #pragma config FUSBIDIO = OFF // USBID pin control

/* Other Peripheral Device settings */ #pragma config FWDTEN = OFF // Watchdog timer enable #pragma config WDTPS = PS1024 // Watchdog timer post-scaler #pragma config FSRSSEL = PRIORITY_7 // SRS interrupt priority #pragma config FCANIO = OFF // Standard/alternate CAN pin select #pragma config FETHIO = ON // Standard/alternate ETH pin select #pragma config FMIIEN = OFF // MII/RMII select (OFF=RMII)

/* Code Protection settings */ #pragma config CP = OFF // Code protection #pragma config BWP = OFF // Boot flash write protect #pragma config PWP = OFF // Program flash write protect

/* Debug settings */ #pragma config ICESEL = ICS_PGx1 // ICE pin selection

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Appendix B: Connector and Jumper Block Pinout Tables

MCU Port Bit to Pmod Connector Pin

MCU Port Bit

RA00 TMS/RA0 JF-07

RA01 TCK/RA1 JF-08

RA02 SCL2/RA2 N/A I2C Bus #2, not shared with Pmod connector

RA03 SDA2/RA3 N/A I2C Bus #2, not shared with Pmod connector

RA04 TDI/RA4 JF-09

RA05 TDO/RA5 JF-10

RA06 TRCLK/RA6 JE-07

RA07 TRD3/RA7 JE-08

RA09 Vref-/CVref-/AERXD2/PMA7/RA9 JE-09

RA10 Vref+/CVref+/AERXD3/PMA6/RA10 JE-10

RA14 AETXCLK/SCL1/INT3/RA14 N/A I2C Bus #1, not shared with Pmod connector

RA15 AETXEN/SDA1/INT4/RA15 N/A I2C Bus #1, not shared with Pmod connector

RB00 PGED1/AN0/CN2/RB0 N/A Used by debug circuit, PGC

RB01 PGEC1/AN1/CN3/RB1 N/A Used by debug circuit, PGD

RB02 AN2/C2IN-/CN4/RB2 JA-01

RB03 AN3/C2IN+/CN5/RB3 JA-02

RB04 AN4/C1IN-/CN6/RB4 JA-03

RB05 AN5/C1IN+/VBUSON/CN7/RB5 N/A USB VBUSON

RB06 PGEC2/AN6/OCFA/RB6 JA-04

RB07 PGED2/AN7/RB7 JA-07

RB08 AN8/C1OUT/RB8 JA-08

RB09 AN9/C2OUT/RB9 JA-09

RB10 CVrefout/PMA13/AN10/RB10 JA-10

RB11 AN11/ERXERR/AETXERR/PMA12/RB11 N/A Ethernet PHY

RB12 AN12/ERXD0/AECRS/PMA11/RB12 N/A Ethernet PHY

RB13 AN13/ERXD1/AECOL/PMA10/RB13 N/A Ethernet PHY

RB14 AN14/ERXD2/AETXD3/PMALH/PMA1/RB14 JC-10

RB15 AN15/…/OCFB/PMALL/PMA0/CN12/RB15 JC-07

RC01 T2CK/RC1 JC-01

RC02 T3CK/AC2TX/RC2 N/A CAN2 Transceiver

RC03 T4CK/AC2RX/RC3 N/A CAN2 Transceiver

RC04 T5CK/SDI1/RC4 JD-03

RC12 OSC1/CLKI/RC12 N/A Primary Oscillator Crystal

RC13 SOSCI/CN1/RC13 N/A Secondary Oscillator Crystal

RC14 SOSCO/T1CK/CN0/RC14 N/A Secondary Oscillator Crystal

RC15 OSC2/CLKO/RC15 N/A Primary Oscillator Crystal

RD00 SDO1/OC1/INT0/RD0 JD-02

RD01 OC2/RD1 JD-07

RD02 OC3/RD2 JD-08

RD03 OC4/RD3 JD-09

RD04 OC5/PMWR/CN13/RD4 JC-09

RD05 PMRD/CN14/RD5 JC-08

RD06 ETXEN/PMD14/CN15/RD6 N/A Ethernet PHY

RD07 ETXCLK/PMD15/CN16/RD7 JC-04

RD08 RTCC/EMDIO/AEMDIO/IC1/RD8 N/A Ethernet PHY

www.digilentinc.com page 11 of 19

Signal Connector

Notes

Cerebot 32MX7 Reference Manual

RD09 SS1/IC2/RD9 JD-01

RD10 SCK1/IC3/PMCS2/PMA15/RD10 JD-04

RD11 EMDC/AEMDC/IC4/PMCS1/PMA14/RD11 N/A Ethernet PHY

RD12 ETXD2/IC5/PMD12/RD12 JD-10

RD13 ETXD3/PMD13/CN19/RD13 N/A BTN3

RD14 AETXD0/SS1A/U1BRX/U1ACTS/CN20/RD14 JE-01

RD15 AETXD1/SCK1A/U1BTX/U1ARTS/CN21/RD15 JE-04

RE00 PMD0/RE0 JB-01

RE01 PMD1/RE1 JB-02

RE02 PMD2/RE2 JB-03

RE03 PMD3/RE3 JB-04

RE04 PMD4/RE4 JB-07

RE05 PMD5/RE5 JB-08

RE06 PMD6/RE6 JB-09

RE07 PMD7/RE7 JB-10

RE08 AERXD0/INT1/RE8 N/A USB Overcurrent detect

RE09 AERXD1/INT2/RE9 N/A Ethernet PHY Reset

RF00 C1RX/ETXD1/PMD11/RF0 N/A Ethernet PHY

RF01 C1TX/ETXD0/PMD10/RF1 N/A Ethernet PHY

RF02 SDA1A/SDI1A/U1ARX/RF2 JE-03

RF03 USBID/RF3 N/A USBID (USB-4)

RF04 SDA3A/SDI3A/U3ARX/PMA9/CN17/RF4 JF-03

RF05 SCL3A/SDO3A/U3ATX/PMA8/CN18/RF5 JF-02

RF08 SCL1A/SDO1A/U1ATX/RF8 JE-02

RF12 AC1RX/SS3A/U3BRX/U3ACTS/RF12 JF-01 shared with CAN1 Transceiver (JP-1)

RF13 AC1TX/SCK3A/U3BTX/U3ARTS/RF13 JF-04 shared with CAN1 Transceiver (JP-2)

RG00 C2RX/PMD8/RG0 JC-02

RG01 C2TX/ETXERR/PMD9/RG1 JC-03

RG02 D+/RG2 N/A D+ (USB-3)

RG03 D-/RG3 N/A D- (USB-2)

RG06 ECOL/SCK2A/U2BTX/U2ARTS/PMA5/CN8/RG6 N/A BTN1

RG07 ECRS/SDA2A/SDI2A/U2ARX/PMA4/CN9/RG7 N/A BTN2

RG08 …/SCL2A/SDO2A/U2ATX/PMA3/CN10/RG8 N/A Ethernet PHY

RG09 …/SS2A/U2BRX/U2ACTS/PMA2/CN11/RG9 N/A Ethernet PHY

RG12 TRD1/RG12 N/A LED1

RG13 TRD0/RG13 N/A LED2

RG14 TRD2/RG14 N/A LED3

RG15 AERXERR/RG15 N/A LED4

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Cerebot 32MX7 Reference Manual

Pmod Connector Pin to MCU Port bit

Connector Pin

JA-01 AN2/C2IN-/CN4/RB2 RB02

JA-02 AN3/C2IN+/CN5/RB3 RB03

JA-03 AN4/C1IN-/CN6/RB4 RB04

JA-04 PGEC2/AN6/OCFA/RB6 RB06

JA-07 PGED2/AN7/RB7 RB07

JA-08 AN8/C1OUT/RB8 RB08

JA-09 AN9/C2OUT/RB9 RB09

JA-10 CVrefout/PMA13/AN10/RB10 RB10

JB-01 PMD0/RE0 RE00

JB-02 PMD1/RE1 RE01

JB-03 PMD2/RE2 RE02

JB-04 PMD3/RE3 RE03

JB-07 PMD4/RE4 RE04

JB-08 PMD5/RE5 RE05

JB-09 PMD6/RE6 RE06

JB-10 PMD7/RE7 RE07

JC-01 T2CK/RC1 RC01

JC-02 C2RX/PMD8/RG0 RG00

JC-03 C2TX/ETXERR/PMD9/RG1 RG01

JC-04 ETXCLK/PMD15/CN16/RD7 RD07

JC-07 AN15/…/OCFB/PMALL/PMA0/CN12/RB15 RB15

JC-08 PMRD/CN14/RD5 RD05

JC-09 OC5/PMWR/CN13/RD4 RD04

JC-10 AN14/ERXD2/AETXD3/PMALH/PMA1/RB14 RB14

JD-01 SS1/IC2/RD9 RD09

JD-02 SDO1/OC1/INT0/RD0 RD00

JD-03 T5CK/SDI1/RC4 RC04

JD-04 SCK1/IC3/PMCS2/PMA15/RD10 RD10

JD-07 OC2/RD1 RD01

JD-08 OC3/RD2 RD02

JD-09 OC4/RD3 RD03

JD-10 ETXD2/IC5/PMD12/RD12 RD12

JE-01 AETXD0/SS1A/U1BRX/U1ACTS/CN20/RD14 RD14

JE-02 SCL1A/SDO1A/U1ATX/RF8 RF08

JE-03 SDA1A/SDI1A/U1ARX/RF2 RF02

JE-04 AETXD1/SCK1A/U1BTX/U1ARTS/CN21/RD15 RD15

JE-07 TRCLK/RA6 RA06

JE-08 TRD3/RA7 RA07

JE-09 Vref-/CVref-/AERXD2/PMA7/RA9 RA09

JE-10 Vref+/CVref+/AERXD3/PMA6/RA10 RA10

JF-01 AC1RX/SS3A/U3BRX/U3ACTS/RF12 RF12 shared with CAN1 Transceiver (JP-1)

JF-02 SCL3A/SDO3A/U3ATX/PMA8/CN18/RF5 RF05

JF-03 SDA3A/SDI3A/U3ARX/PMA9/CN17/RF4 RF04

JF-04 AC1TX/SCK3A/U3BTX/U3ARTS/RF13 RF13 shared with CAN1 Transceiver (JP-2)

JF-07 TMS/RA0 RA00

JF-08 TCK/RA1 RA01

Signal MCU Port

Bit

Notes

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Cerebot 32MX7 Reference Manual

JF-09 TDI/RA4 RA04

JF-10 TDO/RA5 RA05

N/A SCL2/RA2 RA02 I2C bus #2, not shared with Pmod connector

N/A SDA2/RA3 RA03 I2C bus #2, not shared with Pmod connector

N/A AETXCLK/SCL1/INT3/RA14 RA14 I2C Bus #1, not shared with Pmod connector

N/A AETXEN/SDA1/INT4/RA15 RA15 I2C Bus #1, not shared with Pmod connector

N/A PGED1/AN0/CN2/RB0 RB00 Used by debug circuit, PGC

N/A PGEC1/AN1/CN3/RB1 RB01 Used by debug circuit, PGD

N/A AN5/C1IN+/VBUSON/CN7/RB5 RB05 USB VBUSON

N/A AN11/ERXERR/AETXERR/PMA12/RB11 RB11 Ethernet PHY

N/A AN12/ERXD0/AECRS/PMA11/RB12 RB12 Ethernet PHY

N/A AN13/ERXD1/AECOL/PMA10/RB13 RB13 Ethernet PHY

N/A OSC1/CLKI/RC12 RC12 Primary Oscillator Crystal

N/A SOSCI/CN1/RC13 RC13 Secondary Oscillator Crystal

N/A SOSCO/T1CK/CN0/RC14 RC14 Secondary Oscillator Crystal

N/A OSC2/CLKO/RC15 RC15 Primary Oscillator Crystal

N/A ETXEN/PMD14/CN15/RD6 RD06 Ethernet PHY

N/A RTCC/EMDIO/AEMDIO/IC1/RD8 RD08 Ethernet PHY

N/A EMDC/AEMDC/IC4/PMCS1/PMA14/RD11 RD11 Ethernet PHY

N/A ETXD3/PMD13/CN19/RD13 RD13 BTN3

N/A AERXD0/INT1/RE8 RE08 USB Overcurrent detect

N/A AERXD1/INT2/RE9 RE09 Ethernet PHY Reset

N/A C1RX/ETXD1/PMD11/RF0 RF00 Ethernet PHY

N/A C1TX/ETXD0/PMD10/RF1 RF01 Ethernet PHY

N/A USBID/RF3 RF03 USBID (USB-4)

N/A D+/RG2 RG02 D+ (USB-3)

N/A D-/RG3 RG03 D- (USB-2)

N/A ECOL/SCK2A/U2BTX/U2ARTS/PMA5/CN8/RG6 RG06 BTN1

N/A ECRS/SDA2A/SDI2A/U2ARX/PMA4/CN9/RG7 RG07 BTN2

N/A …/SCL2A/SDO2A/U2ATX/PMA3/CN10/RG8 RG08 Ethernet PHY

N/A …/SS2A/U2BRX/U2ACTS/PMA2/CN11/RG9 RG09 Ethernet PHY

N/A TRD1/RG12 RG12 LED1

N/A TRD0/RG13 RG13 LED2

N/A TRD2/RG14 RG14 LED3

N/A AERXERR/RG15 RG15 LED4

www.digilentinc.com page 14 of 19

Cerebot 32MX7 Reference Manual

MCU Pin to Pmod Connector Pin

MCU Port Bit

RG15 1 AERXERR/RG15 N/A LED4

RE05 3 PMD5/RE5 JB-08

RE06 4 PMD6/RE6 JB-09

RE07 5 PMD7/RE7 JB-10

RC01 6 T2CK/RC1 JC-01

RC02 7 T3CK/AC2TX/RC2 N/A CAN2 Transceiver

RC03 8 T4CK/AC2RX/RC3 N/A CAN2 Transceiver

RC04 9 T5CK/SDI1/RC4 JD-03

RG06 10 ECOL/SCK2A/U2BTX/U2ARTS/PMA5/CN8/RG6 N/A BTN1

RG07 11 ECRS/SDA2A/SDI2A/U2ARX/PMA4/CN9/RG7 N/A BTN2

RG08 12 …/SCL2A/SDO2A/U2ATX/PMA3/CN10/RG8 N/A Ethernet PHY

RG09 14 …/SS2A/U2BRX/U2ACTS/PMA2/CN11/RG9 N/A Ethernet PHY

RA00 17 TMS/RA0 JF-07

RE08 18 AERXD0/INT1/RE8 N/A USB Overcurrent detect

RE09 19 AERXD1/INT2/RE9 N/A Ethernet PHY Reset

RB05 20 AN5/C1IN+/VBUSON/CN7/RB5 N/A USB VBUSON

RB04 21 AN4/C1IN-/CN6/RB4 JA-03

RB03 22 AN3/C2IN+/CN5/RB3 JA-02

RB02 23 AN2/C2IN-/CN4/RB2 JA-01

RB01 24 PGEC1/AN1/CN3/RB1 N/A Used by debug circuit, PGD

RB00 25 PGED1/AN0/CN2/RB0 N/A Used by debug circuit, PGC

RB06 26 PGEC2/AN6/OCFA/RB6 JA-04

RB07 27 PGED2/AN7/RB7 JA-07

RA09 28 Vref-/CVref-/AERXD2/PMA7/RA9 JE-09

RA10 29 Vref+/CVref+/AERXD3/PMA6/RA10 JE-10

RB08 32 AN8/C1OUT/RB8 JA-08

RB09 33 AN9/C2OUT/RB9 JA-09

RB10 34 CVrefout/PMA13/AN10/RB10 JA-10

RB11 35 AN11/ERXERR/AETXERR/PMA12/RB11 N/A Ethernet PHY

RA01 38 TCK/RA1 JF-08

RF13 39 AC1TX/SCK3A/U3BTX/U3ARTS/RF13 JF-04 shared with CAN1 Transceiver (JP-2)

RF12 40 AC1RX/SS3A/U3BRX/U3ACTS/RF12 JF-01 shared with CAN1 Transceiver (JP-1)

RB12 41 AN12/ERXD0/AECRS/PMA11/RB12 N/A Ethernet PHY

RB13 42 AN13/ERXD1/AECOL/PMA10/RB13 N/A Ethernet PHY

RB14 43 AN14/ERXD2/AETXD3/PMALH/PMA1/RB14 JC-10

RB15 44 AN15/…/OCFB/PMALL/PMA0/CN12/RB15 JC-07

RD14 47 AETXD0/SS1A/U1BRX/U1ACTS/CN20/RD14 JE-01

RD15 48 AETXD1/SCK1A/U1BTX/U1ARTS/CN21/RD15 JE-04

RF04 49 SDA3A/SDI3A/U3ARX/PMA9/CN17/RF4 JF-03

RF05 50 SCL3A/SDO3A/U3ATX/PMA8/CN18/RF5 JF-02

RF03 51 USBID/RF3 N/A USBID (USB-4)

RF02 52 SDA1A/SDI1A/U1ARX/RF2 JE-03

RF08 53 SCL1A/SDO1A/U1ATX/RF8 JE-02

RG03 56 D-/RG3 N/A D- (USB-2)

RG02 57 D+/RG2 N/A D+ (USB-3)

RA02 58 SCL2/RA2 N/A I2C Bus #2, not shared with Pmod connector

MCU

Signal Connector

Notes

www.digilentinc.com page 15 of 19

Cerebot 32MX7 Reference Manual

RA03 59 SDA2/RA3 N/A I2C Bus #2, not shared with Pmod connector

RA04 60 TDI/RA4 JF-09

RA05 61 TDO/RA5 JF-10

RC12 63 OSC1/CLKI/RC12 N/A Primary Oscillator Crystal

RC15 64 OSC2/CLKO/RC15 N/A Primary Oscillator Crystal

RA14 66 AETXCLK/SCL1/INT3/RA14 N/A I2C Bus #1, not shared with Pmod connector

RA15 67 AETXEN/SDA1/INT4/RA15 N/A I2C Bus #1, not shared with Pmod connector

RD08 68 RTCC/EMDIO/AEMDIO/IC1/RD8 N/A Ethernet PHY

RD09 69 SS1/IC2/RD9 JD-01

RD10 70 SCK1/IC3/PMCS2/PMA15/RD10 JD-04

RD11 71 EMDC/AEMDC/IC4/PMCS1/PMA14/RD11 N/A Ethernet PHY

RD00 72 SDO1/OC1/INT0/RD0 JD-02

RC13 73 SOSCI/CN1/RC13 N/A Secondary Oscillator Crystal

RC14 74 SOSCO/T1CK/CN0/RC14 N/A Secondary Oscillator Crystal

RD01 76 OC2/RD1 JD-07

RD02 77 OC3/RD2 JD-08

RD03 78 OC4/RD3 JD-09

RD12 79 ETXD2/IC5/PMD12/RD12 JD-10

RD13 80 ETXD3/PMD13/CN19/RD13 N/A BTN3

RD04 81 OC5/PMWR/CN13/RD4 JC-09

RD05 82 PMRD/CN14/RD5 JC-08

RD06 83 ETXEN/PMD14/CN15/RD6 N/A Ethernet PHY

RD07 84 ETXCLK/PMD15/CN16/RD7 JC-04

RF00 87 C1RX/ETXD1/PMD11/RF0 N/A Ethernet PHY

RF01 88 C1TX/ETXD0/PMD10/RF1 N/A Ethernet PHY

RG01 89 C2TX/ETXERR/PMD9/RG1 JC-02

RG00 90 C2RX/PMD8/RG0 JC-03

RA06 91 TRCLK/RA6 JE-07

RA07 92 TRD3/RA7 JE-08

RE00 93 PMD0/RE0 JB-01

RE01 94 PMD1/RE1 JB-02

RG14 95 TRD2/RG14 N/A LED3

RG12 96 TRD1/RG12 N/A LED1

RG13 97 TRD0/RG13 N/A LED2

RE02 98 PMD2/RE2 JB-03

RE03 99 PMD3/RE3 JB-04

RE04 100 PMD4/RE4 JB-07

www.digilentinc.com page 16 of 19

Cerebot 32MX7 Reference Manual

Label

Function

J7 I2C port #2 daisy chain connector

J8 I2C port #1 daisy chain connector

J9 CAN #1 Connector

J10 CAN #2 Connector

J11 Ethernet Connector

J12

Do Not Use

J15 Debug USB Connector

J16 Power supply source select

J17 External Power Connector

J18 External Power Connector

J19 USB Device / OTG Connector

Appendix C: Connector Descriptions and Jumper Settings

This connector provides access to the I2C signals, power and ground for I2C port #2.

This connector provides access to the I2C signals, power and ground for I2C port #1.

This connector is used to access the signals for CAN #1.

This connector is used to access the signals for CAN #2.

This connector provides access to the 10/100 Ethernet port.

J14

This connector is used to connect the on-board programming and debug circuit to the PC for use with the MPLAB IDE.

This jumper is used to select the source of main board power.

Place a shorting block in the upper, “USB” position to have the board powered from the USB device connector, J19.

Place a shorting block in the center, “EXT” position to have the board powered from one of the external power connectors, J17 or J18.

Place a shorting block in the lower, “DBG” position to have the board powered from the debug USB connector, J15.

This is a 2.5mm x 5.5mm, center positive, coax power connector used to provide external power to the board. The optional Digilent 5V Switching Power Supply is connected here.

This is a screw terminal connector used to provide external power to the board. Be sure to observe proper polarity (marked near the connector) when providing power via this connector, or damage to the board and/or connected devices may result.

This is a USB micro-AB connector. It is used when using the PIC32MX795 microcontroller to implement a USB device or OTG Host/Device.

www.digilentinc.com page 17 of 19

Cerebot 32MX7 Reference Manual

J20 USB Host Connector

JP1 &

CAN or Pmod Select

JP3 &

Pull

up enable for I2C port #2

JP5 CAN #1 Termination

JP6 CAN #1 5V0 Enable

JP7 CAN #2 Termination

JP8 CAN #1 5V0 Enable

JP9 Do Not Use

JP10

USB host power select

JP17

Do Not Use

JA-JF Pmod Connectors

JPA

– Pmod header power select

This is a standard sized USB type A connector. This connector is used to connect USB devices to the board when using the PIC32MX795 microcontroller to implement an embedded USB host.

JP2

JP4

These jumpers select microcontroller signals RF12 and RF13 for use with CAN #1 or Pmod connector JF. Place these jumpers in the CAN position to use CAN #1. Place the jumpers in the PMOD position to use then with Pmod connector JF.

These two jumpers are used to enable/disable the pull-up resistors on I2C port #2. Insert shorting blocks on these two jumpers to enable the pull-up resistors. Remove the shorting blocks to disable the pull-up resistors. Only a single device on the I2C bus should have the pull-up resistors enabled.

This jumper is used to enable/disable the 120 ohm termination resistor for CAN #1. Insert the shorting block to enable the termination resistor, remove it to disable the termination resistor.

This jumper is used to enable/disable providing 5V to the CAN #1 connector. Insert the shorting block to connect the board 5V0 supply to pins 9 & 10 of CAN #1 connector. Remove the shorting block to disconnect the 5V0 supply.

This jumper is used to enable/disable the 120 ohm termination resistor for CAN #2. Insert the shorting block to enable the termination resistor, remove it to disable the termination resistor.

This jumper is used to select which host connector is powered when host power is enabled. Place the shorting block in the “MICRO” position to supply power to the USB micro-AB OTG Connector, J19. Place the shorting block in the “A” position to supply power to the USB type A Host Connector, J20.

These connectors provide access to the I/O pins on the PIC32MX795 microcontroller. Digilent Pmod peripheral modules can be attached to these connectors.

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Cerebot 32MX7 Reference Manual

JPF

Any of the Pmod connectors can provide either regulated or unregulated power. To use regulated power, place the jumper block over the center pin and the pin marked 3V3. To use unregulated power, place the jumper block over the center pin and the pin marked 5V0.

www.digilentinc.com page 19 of 19

Digilent 32MX7 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual