Digilent Cerebot 32MX7 Reference Manual

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Revision: June 27, 2011 Note: This document applies to REV C of the board.

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Cerebot 32MX7 Circuit Diagram

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 peripheral modules include H-bridges, analog-to-digital and digital-to-analog converters, 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

 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 Debug Using MPLAB

The Cerebot 32MX7 board is intended to be used with the Microchip MPLAB IDE for firmware development, programming and insystem debug. 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 part 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. Use the Debugger.Select Tool menu, or the Programmer.Select Tool menu, and select “Licensed Debugger” as the programmer or debugger.

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

Cerebot 32MX7 Reference Manual

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 available, the 5V Switching 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 6 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 other than 5V, some features of the board won‟t work.

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.

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 told 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.

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Cerebot 32MX7 Reference Manual

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 voltage external supply 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 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.

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

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Cerebot 32MX7 Reference Manual

block in the “A” position when using the standard USB type A (host) Connector, J20. 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 provide a standard 10/100 Ethernet interface.

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 32MX7 is designed to use the standard (not

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Cerebot 32MX7 Reference Manual

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.

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:

#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

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Cerebot 32MX7 Reference Manual

SCL

SDA

SCL

SDA

Pull-ups Enabled

Pull-ups Disabled

3V3

GND

3V3

GND

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

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 I2C pull-up resistors on I2C bus #2 on the Cerebot 32MX7 board are actually implemented using current mirrors rather than

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

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.

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 port #1 while connector J7 provides access to I2C port #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. I2C bus #1 has permanently connected pull-up resistors. I2C bus #2 provides selectable pull-up resistors that can be enabled or disabled via jumper

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 bus #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 peripheral modules that provide various kind of I/O interfaces. The Pmod line includes such

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Cerebot 32MX7 Reference Manual

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. 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.

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 to select the

ED option and #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 8Mhz oscillator to produce CPU operating frequencies up to 80Mhz. The operating frequency is selected via the PIC32MX795 configuration variables. These are set using the #pragma config statement. Use #pragma config FPLLMUL to set the multiplication factor and #pragma

config FPLLDIV to set the divider for the

internal phased lock loop in the PIC32 microcontroller. Refer to the data sheet for the PIC32MX7XX family devices for information on how to choose the correct values, as not all combination of multiplication and division factor will work.

When a button is pressed, the corresponding bit will be high („1‟).

The four LEDs are connected to bits 12-15 of PORTG. LED 1 is connected to bit 12, LED 2

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Cerebot 32MX7 Reference Manual

MCU Port Bit to Pmod Connector Pin

MCU Port Bit

Signal

Connector Pin

Notes

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

Connector and Jumper Block Pinout Tables

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Cerebot 32MX7 Reference Manual

RD08

RTCC/EMDIO/AEMDIO/IC1/RD8

N/A

Ethernet PHY

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

www.digilentinc.com page 10 of 17

Cerebot 32MX7 Reference Manual

Pmod Connector Pin to MCU Port bit

Connector Pin

Signal

MCU Port Bit

Notes

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

www.digilentinc.com page 11 of 17

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 12 of 17

Cerebot 32MX7 Reference Manual

MCU Pin to Pmod Connector Pin

MCU Port Bit

MCU

Signal

Connector Pin

Notes

RG15

AERXERR/RG15

N/A

LED4

RE05

PMD5/RE5

JB-08

RE06

PMD6/RE6

JB-09

RE07

PMD7/RE7

JB-10

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

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

RA00

TMS/RA0

JF-07

RE08

AERXD0/INT1/RE8

N/A

USB Overcurrent detect

RE09

AERXD1/INT2/RE9

N/A

Ethernet PHY Reset

RB05

AN5/C1IN+/VBUSON/CN7/RB5

N/A

USB VBUSON

RB04

AN4/C1IN-/CN6/RB4

JA-03

RB03

AN3/C2IN+/CN5/RB3

JA-02

RB02

AN2/C2IN-/CN4/RB2

JA-01

RB01

PGEC1/AN1/CN3/RB1

N/A

Used by debug circuit, PGD

RB00

PGED1/AN0/CN2/RB0

N/A

Used by debug circuit, PGC

RB06

PGEC2/AN6/OCFA/RB6

JA-04

RB07

PGED2/AN7/RB7

JA-07

RA09

Vref-/CVref-/AERXD2/PMA7/RA9

JE-09

RA10

Vref+/CVref+/AERXD3/PMA6/RA10

JE-10

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

RA01

TCK/RA1

JF-08

RF13

AC1TX/SCK3A/U3BTX/U3ARTS/RF13

JF-04

shared with CAN1 Transceiver (JP-2)

RF12

AC1RX/SS3A/U3BRX/U3ACTS/RF12

JF-01

shared with CAN1 Transceiver (JP-1)

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

RD14

AETXD0/SS1A/U1BRX/U1ACTS/CN20/RD14

JE-01

RD15

AETXD1/SCK1A/U1BTX/U1ARTS/CN21/RD15

JE-04

RF04

SDA3A/SDI3A/U3ARX/PMA9/CN17/RF4

JF-03

RF05

SCL3A/SDO3A/U3ATX/PMA8/CN18/RF5

JF-02

RF03

USBID/RF3

N/A

USBID (USB-4)

RF02

SDA1A/SDI1A/U1ARX/RF2

JE-03

RF08

SCL1A/SDO1A/U1ATX/RF8

JE-02

RG03

D-/RG3

N/A

D- (USB-2)

RG02

D+/RG2

N/A

D+ (USB-3)

RA02

SCL2/RA2

N/A

I2C Bus #2, not shared with Pmod connector

www.digilentinc.com page 13 of 17

Cerebot 32MX7 Reference Manual

RA03

SDA2/RA3

N/A

I2C Bus #2, not shared with Pmod connector

RA04

TDI/RA4

JF-09

RA05

TDO/RA5

JF-10

RC12

OSC1/CLKI/RC12

N/A

Primary Oscillator Crystal

RC15

OSC2/CLKO/RC15

N/A

Primary Oscillator Crystal

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

RD08

RTCC/EMDIO/AEMDIO/IC1/RD8

N/A

Ethernet PHY

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

RD00

SDO1/OC1/INT0/RD0

JD-02

RC13

SOSCI/CN1/RC13

N/A

Secondary Oscillator Crystal

RC14

SOSCO/T1CK/CN0/RC14

N/A

Secondary Oscillator Crystal

RD01

OC2/RD1

JD-07

RD02

OC3/RD2

JD-08

RD03

OC4/RD3

JD-09

RD12

ETXD2/IC5/PMD12/RD12

JD-10

RD13

ETXD3/PMD13/CN19/RD13

N/A

BTN3

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

RF00

C1RX/ETXD1/PMD11/RF0

N/A

Ethernet PHY

RF01

C1TX/ETXD0/PMD10/RF1

N/A

Ethernet PHY

RG01

C2TX/ETXERR/PMD9/RG1

JC-02

RG00

C2RX/PMD8/RG0

JC-03

RA06

TRCLK/RA6

JE-07

RA07

TRD3/RA7

JE-08

RE00

PMD0/RE0

JB-01

RE01

PMD1/RE1

JB-02

RG14

TRD2/RG14

N/A

LED3

RG12

TRD1/RG12

N/A

LED1

RG13

TRD0/RG13

N/A

LED2

RE02

PMD2/RE2

JB-03

RE03

PMD3/RE3

JB-04

RE04

100

PMD4/RE4

JB-07

www.digilentinc.com page 14 of 17

Cerebot 32MX7 Reference Manual

Label

Function

I2C port #2 daisy chain connector

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

I2C port #1 daisy chain connector

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

CAN #1 Connector

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

J10

CAN #2 Connector

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

J11

Ethernet Connector

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

J12J14

Do Not Use.

J15

Debug USB Connector

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

J16

Power supply source select

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.

J17

External Power Connector

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.

J18

External Power Connector

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.

J19

USB Device / OTG Connector

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

Connector Descriptions and Jumper Settings

www.digilentinc.com page 15 of 17

Cerebot 32MX7 Reference Manual

J20

USB Host Connector

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.

JP1 & JP2

CAN or Pmod Select

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.

JP3 & JP4

Pull-up enable for I2C port #2

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.

JP5

CAN #1 Termination

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.

JP6

CAN #1 5V0 Enable

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.

JP7

CAN #2 Termination

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.

JP8

CAN #1 5V0 Enable

JP9

Do Not Use

JP10

USB host power select

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.

JP17

Do Not Use

JA-JF

Pmod Connectors

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

JPA –

Pmod header power select

www.digilentinc.com page 16 of 17

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 17 of 17

Digilent Cerebot 32MX7 Reference Manual

Specifications and Main Features

Frequently Asked Questions

User Manual