Cerebot MX7cK™ Board
Reference Manual
Revision: June 24, 2013
Note: This document applies to REV B and C of the board.
1300 Henley Court | Pullman, WA 99163
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Overview
The Cerebot MX7cK is a microcontroller
development board based on the Microchip
PIC32MX795F512L, a member of the 32-bit
PIC32 microcontroller family. It is compatible
with Digilent’s line of Pmod™ peripheral
modules, and is suitable for use with the
Microchip MPLAB® IDE tools. The Cerebot
MX7cK is also compatible for use with the
chipKIT™ MPIDE development environment.
ChipKIT and MPIDE is a PIC32 based system
compatible with many existing Arduino™ code
examples, reference materials and other
resources.
The Cerebot MX7cK is designed to be easy to
use and suitable for use by anyone from
beginners to advanced users for experimenting
with embedded control and network
communications application. A built in
programming/debugging circuit compatible with
the Microchip MPLAB® IDE is provided, so no
additional hardware is required for use with
MPLAB. The kit contains everything needed to
start developing embedded applications using
either the MPLAB® IDE or the MPIDE.
The Cerebot MX7cK provides 52 I/O pins that
support a number of peripheral functions, such
as UART, SPI and I2C™ ports as well as five
pulse width modulated outputs and five
external interrupt inputs. Its network and
communications features also include a 10/100
Ethernet interface, Full Speed USB 2.0 OTG
interface, and dual CAN network interfaces.
Ten of the I/O pins can be used as analog
inputs in addition to their use as digital inputs
and outputs.
Cerebot MX7cK Circuit Diagram
The Cerebot MX7cK can be powered in
various ways via USB, or using an external
AC-DC power adapter.
Doc: 502-223
page 1 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
Functional Description
The Cerebot MX7cK is designed for embedded
control and network communications
applications as well as for general
microprocessor experimentation. Firmware
suitable for many applications can be
downloaded to the Cerebot MX7cK’s
programmable PIC32 microcontroller.
Features of the Cerebot MX7cK include:
a PIC32MX795F512L microcontroller
support for programming and
debugging within the Microchip MPLAB
development environment
support for programming within the
chipKIT MPIDE development
environment
six Pmod connectors for Digilent
peripheral module boards
10/100 Ethernet
USB 2.0 compatible 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.
Features of the PIC32MX795F512L include:
512KB internal program flash memory
128KB internal SRAM memory
USB 2.0 compliant full-speed On-TheGo (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
www.digilentinc.com
two analog comparators
The Cerebot MX7cK has a number of
input/output connection options, and is
designed to work with the Digilent line of Pmod
peripheral modules that provide 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 MX7cK 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 the debug USB port,
the USB UART serial port, or the USB device
port. It can also be powered from an external
5V power supply.
Programming Tools
The Cerebot MX7cK can be used with either
the Microchip MPLAB® development
environment or the chipKIT MPIDE
development environment. When used with the
MPLAB® IDE, in-system-programming and
debugging of firmware running on the
PIC32MX795 microcontroller is supported
using an on-board programming/debugging
circuit licensed from Microchip.
The Cerebot MX7cK is immediately useable
with either the MPLAB IDE or the chipKIT
MPIDE. No additional hardware is required to
use the board with the Microchip MPLAB tools.
Using the Cerebot MX7cK with
Microchip Development Tools
The Microchip MPLAB® IDE or the MPLAB® X
IDE can be used to program and debug code
running on the Cerebot MX7cK board using the
built-in programming/debugging circuit.
The MPLAB development environment can be
downloaded from the Microchip web site. This
software suite includes a free evaluation copy
page 2 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
of the Microchip C32 compiler for use with the
PIC32 microcontroller family. The licensed
debugger is compatible with the MPLAB IDE
version 8.63 or later or all versions of MPLAB
X.
When creating a new project, use the
“Configure.Select Device…” menu to specify the
PIC32 device being used. Ensure that the
device is set to PIC32MX795F512L.
In order to use the on-board
programming/debugging 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 licensed debugger interface uses USB
connector J15, labeled DEBUG. Connector
J15 is a USB micro-B connector located on the
left side of the board below the Ethernet RJ45
connector. Use a USB-A to micro-B cable
(provided with the board) to connect to an
available USB port on the PC.
When the licensed debugger is selected as the
programming or debugging device, the MPLAB
IDE will check the version number of the
firmware running on the debugger and offer to
update if it is out of date with the version of
MPLAB being used.
The PIC32 in-system programming/debugging
interface uses two pins on the microcontroller.
These devices support two alternate pin pairs
for this interface: PGC1/PGD1 or PGC2/PGD2.
The PGC2/PGD2 pair is used by default. Due
to conflicting uses of the microcontroller pins,
the Cerebot MX7cK is designed to use the
PGC1/PGD1 pair of pins. 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:
www.digilentinc.com
#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.
The MCLR pin on the PIC32 microcontroller is
used by the hardware programming/debugging
interface to reset the processor. This same pin
is used by the USB serial converter to reset the
processor when using the MPIDE. It is possible
that the reset function from the USB serial
interface can interfere with correct operation of
the Microchip programming and debugging
tools. If this happens, jumper JP11 can be
used to disconnect the USB serial converter
reset circuit. Remove the shorting block from
JP11 to disable the reset circuit. If the shorting
block has been removed, it is necessary to
reinstall it on JP11 in order to use the Cerebot
MX7cK board with the MPIDE again.
Using the Microchip development tools to
program the Cerebot MX7cK will erase the
chipKIT boot loader. To use the board with the
chipKIT MPIDE again, it is necessary to
program the boot loader back onto the board.
The programming file for the boot loader
programmed into the board by Digilent at the
factory is available for download from the
product page for the Cerebot MX7cK on the
Digilent web site. Additionally, the boot loader
source code is available in the chipKIT project
repository at www.github.com/chipKIT32/pic32Arduino-Bootloader.
To reprogram the boot loader using MPLAB,
perform the following steps:
Use the “Configure.Select Device …” menu to
select the PIC32MX795F512L
Use the “Programmer.Select Programmer”
menu to select the “Licensed Debugger”.
Use the “File Import…” dialog box to
navigate to and select the boot loader
programming downloaded from the Digilent
web site. The file name will be something
like: chipKIT_Bootloader_MX7cK.hex
Use the “Programmer.Program” command to
program all memories on the device.
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Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
Using the Cerebot MX7cK with the
chipKIT MPIDE
ChipKIT and the MPIDE is a PIC32 based
hardware and software system compatible with
many existing Arduino™ code examples,
reference materials and other resources. The
MPIDE development platform was produced by
modifying the Arduino™ IDE and is fully
backward compatible with the Arduino IDE.
The Cerebot MX7cK board is designed to be
fully compatible with the chipKIT MPIDE
system, version 20111221 or later.
The MPIDE uses a serial communications port
to communicate with a boot loader running in
the target board. The serial port on the MX7cK
board is implemented using an FTDI FT232R
USB serial converter. Before attempting to use
the MPIDE with the MX7cK, the appropriate
USB device driver must be installed.
Driving the MCLR line low resets the
microcontroller, restarting execution with the
boot loader.
The automatic reset action when the serial
communications connection is opened can be
disabled. To disable this operation, remove the
shorting block from jumper JP11. The shorting
block is reinstalled on JP11 to restore
operation with the MPIDE.
Two red LEDs (LD9 and LD10) will blink when
data is being sent or received between the
Cerebot MX7cK and the PC over the serial
connection.
The header connector J1 provides access to
the other serial handshaking signals provided
by the FT232R. Connector J1 is not loaded at
the factory but can be installed by the user to
access these signals.
Additional Reference Documentation
The USB serial converter on the Cerebot
MX7cK uses USB connector J2, labeled UART
on the board. This connector is a USB microAB, and is located on the lower left side of the
board adjacent to the power switch. Use a
standard USB-A to micro-B cable (provided
with the board) to connect the board to an
available USB port on the PC.
In the MPIDE, use the “Tools.Board” command
to select the Cerebot MX7cK from the list of
available boards. Use the “Tools.Serial Port”
command to choose the appropriate serial port
from the list of available serial ports on the PC.
When the MPIDE needs to communicate with
the MX7cK board, the PIC32 microcontroller is
reset and starts running the boot loader. The
MPIDE then establishes communications with
the boot loader and downloads the user’s
program, programming it into the flash memory
in the microcontroller
When the MPIDE opens the serial
communications connection on the PC, the
DTR pin on the FT232R chip is driven low.
This pin is coupled through a capacitor to the
MCLR pin on the PIC32 microcontroller.
www.digilentinc.com
Additional information about the Cerebot
MX7cK board and the use and operation of the
PIC32MX795F512L microcontroller can be
obtained from the following sources.
The Cerebot MX7cK Schematic, as well as
various support libraries, and example
reference designs are available on the board
product page on the Digilent web site:
www.digilentinc.com
The PIC32MX5XX/6XX/7XX Family Data
Sheet and the PIC32MX Family Reference
Manual available from the Microchip web site:
www.microchip.com
Reference material for the chipKIT MPIDE
system is included in the MPIDE software
download, and on-line in the chipKIT wiki. Help
with questions and problems using the board
with the chipKIT MPIDE software can also be
obtained in the chipKIT forums:
www.github.com/chipKIT32 (software
download)
www.chipKIT.org/wiki
www.chipKIT.org/forum
page 4 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
Board Hardware Description
The following describes the various hardware
features of the Cerebot MX7cK board and the
PIC32XM795F512L microcontroller.
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.
The Cerebot MX7cK may be USB powered via
either the USB debug port, the USB UART
port, or the USB device port. Alternatively, the
board may be powered via dedicated,
“external”, power supply connectors.
Jumper block J3 selects the power source
used to provide power to the board. This
jumper block provides the following four
positions:
USB – power is supplied by USB device
connector J19. This is used when the
Cerebot MX7cK is being used to implement
a USB bus powered device.
EXT – Power is supplied by one of the
external power connectors.
DBG – Power is supplied by DEBUG USB
connector J15.
UART – Power is supplied by UART USB
connector J2.
Place the shorting block in the appropriate
position on J3 for the desired power source for
the board.
The Cerebot MX7cK 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. If the board is operated from
an external supply with a voltage less than 5V,
some features won’t work correctly.
The USB specification requires that USB
devices not draw more than 100mA of current
www.digilentinc.com
until they have enumerated on the USB bus
and informed the host that they want to
consume more current. To meet this
specification, the debugger 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 powered 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.
The power supply selected by the shorting
block on J3 will appear on the input power
supply bus, labeled VIN in the schematic. This
voltage is regulated to 3.3V to power the
licensed debugger circuit by IC11, a Microchip
MCP1801 Low Dropout voltage regulator. This
regulator is turned on and the debugger circuit
is powered whenever the power switch is in the
on position. The VIN power bus also supplies
power to IC9, a PFET load switch used to turn
main board power on or off.
When the power switch is turned on, transistor
Q7A attempts to drive the ON/OFF pin of IC9
high to enable the main power supply.
If the licensed debugger is connected to an
active USB port, it initially disables the main
power supply by holding the PWR_ON signal
low. This causes Q8B to hold the ON/OFF pin
of IC9 low, forcing the main supply off. The
licensed debugger will enumerate with the host
computer and once it has successfully
enumerated, will turn on the main board power
supply by driving the PWR_ON signal high.
If the licensed debugger is not connected to an
active USB port, the signal labeled DBG5V0
will not be powered. Transistor Q8B will be
unable to hold the ON/OFF pin low and the
page 5 of 36
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Cerebot MX7cK Reference Manual
main power supply will be turned on
immediately when the power switch is turned
on. When load switch IC9 is turned on, it
powers the board unregulated power bus
VCC5V0, which provides the input power to
the main regulator.
The main board power supply is a switch mode
voltage regulator implemented using a
Microchip MCP16301 switch mode step-down
regulator, IC10. This regulator provides 3.3V at
up to 600 mA with approximately 96%
efficiency. When the main power supply is
enabled, it powers the regulated power bus
VCC3V3
When powering the board from an external
power supply, there are two 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 a 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.
Connectors J17 and J18 are wired in parallel
and connect to the EXT position on the Power
Select jumper block J3. A shorting block
should be placed on the “EXT” position of J3
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.
When the Cerebot MX7cK 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 MX7cK board, this supply provides the
www.digilentinc.com
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.
The PIC32 microcontroller and on-board I/O
devices operate at a supply voltage of 3.3V
provided by the VCC3V3 bus. The main
voltage regulator is capable of providing a
maximum of 600mA 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 Cerebot MX7cK 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
connectors only provide the regulated voltage,
VCC3V3.
Pmod™ Connectors
The Cerebot MX7cK has six connectors for
connecting Digilent Pmod peripheral modules.
The Pmod connectors, labeled JA–JF, are 2x6
pin, right-angle, female pin header connectors.
Each connector has an associated power
select jumper block labeled JPA–JPF.
page 6 of 36
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Cerebot MX7cK Reference Manual
Digilent Pmods are a line of small peripheral
modules that provide various kinds of I/O
interfaces. The Pmod product line includes
such things as button, switch and LED
modules, connector modules, LCD displays,
high current output drivers, various kinds of RF
interfaces, 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. All of the Pmod
connectors on the Cerebot MX7cK are twelve
pin connectors.
Six-pin Pmod 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. Pins 1–4 and 7–10 are the signal
pins, pins 5 and 11 are the ground pins and
pins 6 & 12 are the power supply pins.
The pin numbering that Digilent uses on the
twelve-pin Pmod connectors is non-standard.
The upper row of pins are numbered 1–6, left
to right (when viewed from the top of the
board), and the lower row of pins are
numbered 7–12, left to right. This is in keeping
with the convention that the upper and lower
rows of pins can be considered to be two sixpin connectors stacked. When viewed from the
end of the connector, pin 1 is the upper right
pin and pin 7 is immediately below it (closer to
the PCB).
Each Pmod connector has an associated
power select jumper. These are used to select
the power supply voltage supplied to the power
supply pins on the Pmod connector. They are
switchable between either the unregulated
power supply, VCC5V0 or the 3.3V main board
supply, VCC3V3. Place the shorting block in
the 3V3 position for regulated 3.3V and in the
5V0 position to use the unregulated supply.
www.digilentinc.com
Each signal pin on the Pmod connectors is
connected to an input/output pin on the PIC32
microcontroller. 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.
The 200 ohm resistor in series with each I/O
pin limits the amount of current that can be
sourced from the microcontroller pins. There
will be a 200mV voltage drop per mA of current
sourced by the pin. This will not be a problem
when driving typical, high impedance, logic
inputs, but can be problematic when trying to
drive low impedance inputs. If some cases, it
may be necessary to use external buffers
when trying to drive low impedance inputs.
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 Pmod peripheral modules can either
be plugged directly into the connectors on the
Cerebot MX7cK or attached via cables.
Digilent has a variety of Pmod interconnect
cables available.
See the Pinout Tables in Appendix C, below,
for more information about connecting
peripheral modules and other devices to the
Cerebot MX7cK. These tables describe the
mapping between pins on the PIC32MX795
microcontroller and the pins on the various
connectors.
The PIC32 microcontroller can source or sink a
maximum of 18mA on all digital I/O pins.
However, to keep the output voltage within the
specified input/output voltage range (V OL 0.4V,
VOH 2.4V) the pin current must be restricted to
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Cerebot MX7cK Reference Manual
+7/-12mA. The maximum current that can be
sourced or sunk across all I/O pins
simultaneously is +/-200mA. The maximum
voltage that can be applied to any digital I/O
pin is 5.5V. The maximum voltage that can be
applied to any analog input capable pin is
3.6V. For more detailed specifications, refer to
the PIC32MX5XX/6XX/7XX Family Data
Sheet.
Digital Inputs and Outputs
The Cerebot MX7cK board provides access to
48 of the I/O pins from the PIC32MX795
microcontroller via the Pmod connectors. Four
additional I/O pins can be accessed via the I2C
connectors, J7 and J8. Any of the pins on the
Pmod or I2C connectors can be individually
accessed for digital input or output. Note that
when the I2C signals on J7 or J8 are being
used for I2C communications, they are not
available for general purpose I/O.
On PIC32 microcontrollers, the input/output
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 particular PIC32
microcontroller, some of the I/O Ports are not
present, and not all 16 bits are present in all
I/O Ports.
Each I/O Port has four associated registers:
TRIS, LAT, PORT, and ODC. The registers for
I/O Port A are named TRISA, LATA, PORTA
and ODCA. The registers for the other I/O
Ports are named similarly.
The TRIS register is used to set the pin
direction. Setting a TRIS bit to 0 makes the 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 current state of all of the pins in the I/O
Port. Writing to the PORT register is equivalent
to writing to the LAT register.
PIC32 microcontrollers allow any pin set as an
output to be configured as either a normal
totem-pole 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.
Refer to the PIC32MX5XX/6XX/7XX Family
Data Sheet, 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.
Pmod connector JF, pins 8, 9, and 10 are
connected to the signals TCK/RA1, TDI/RA4,
and TDO/RA5 respectively. These
microcontroller pins are shared between
general purpose I/O functions and use by the
JTAG controller. The JTAG controller is
enabled on reset, so these pins are not
available for general purpose I/O until the
JTAG controller is disabled. The following
statement can be used to disable the JTAG
controller:
DDPCONbits.JTAGEN = 0;
The JTAG controller is disabled by the startup
initialization code in the MPIDE runtime. It is
not necessary to disable the JTAG controller
when using the board with MPIDE.
The chipKIT MPIDE system uses logical pin
numbers to identify digital I/O pins on the
connectors. These pin numbers start with pin 0
and are numbered up consecutively.
On the Cerebot MX7cK, pin numbers 0-47 are
used to access the pins on the Pmod
connectors and pin numbers 55-58 are used
for the signal pins on the I2C connectors, J7
and J8. The pin numbers are assigned so that
connector JA pin 1 (JA-01) is digital pin 0, JA
pin 2 (JA-02) is digital pin 1, and so on.
The PORT register is used to read from the I/O
Port. Reading from the PORT register returns
www.digilentinc.com
page 8 of 36
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Cerebot MX7cK Reference Manual
Pins 0-7 are on connector JA, pins 8-15 on JB,
pins 16-23 on JC, pins 24-31 and so on. Refer
to the tables in Appendix B for detailed
information about the pin mapping between
Pmod connector, logical pin number, and
PIC32 microcontroller pin number and pin
function.
When using the Cerebot MX7cK with the
chipKIT MPIDE the functions pinMode(),
digitalRead(), and digitalWrite() are used for
digital pin I/O.
The pinMode() function is used to set the pin
direction. Pin direction can be set to: INPUT,
OUTPUT, or OPEN. OPEN is used for opendrain and implies output.
The digitalRead() and digitalWrite() functions
are used to read or write the pins.
DigitalRead() returns the current state of the
specified pin, and digitalWrite is used to set the
state of an output pin. The pin state can be
either HIGH or LOW.
Push Buttons and LEDs
The Cerebot MX7cK board provides three
push button switches for user input and four
LEDs for output. The buttons, BTN1 and BTN2
are connected to I/O Port G, bits 6 and 7
respectively. BTN3 is connected to I/O Port A,
bit 0. To read the buttons, pins 6 and 7 of I/O
Port G and pin 0 of I/O Port A must be
configured as inputs by setting the
corresponding bits in the TRISG and TRISA
registers. The button state is then obtained by
reading the PORTG or PORTA registers.
When a button is pressed, the corresponding
bit will be high (‘1’). The pins used by the
buttons are dedicated to this use and do not
appear on any connector.
Button BTN3 is connected to the signal
TMS/RA0 on the PIC32 microcontroller. This
microcontroller pin is shared between general
purpose I/O functions and use by the JTAG
controller. The JTAG controller is enabled on
reset, and so BTN3 is not useable as a button
input until the JTAG controller is disabled. The
www.digilentinc.com
following statement can be used to disable the
JTAG controller:
DDPCONbits.JTAGEN = 0;
The JTAG controller is disabled by the startup
initialization code in the MPIDE runtime. It is
not necessary to disable the JTAG controller
when using the board with MPIDE.
The four LEDs are connected to bits 12-15 of
I/O Port G. LED 1 is connected to bit 12, LED 2
is connected to bit 13, and so on. These four
pins are dedicated to use with the LEDs and
do not appear on any connector pin. To use
the LEDs, configure the desired bits as outputs
by clearing the corresponding bits in the
TRISG register. The state of an LED is set by
writing values to the LATG register. Setting a
bit to 1 will illuminate the LED and setting the
bit to 0 will turn it off.
When using the MPIDE and the chipKIT
system, the buttons are accessed using
digitalRead() and the LEDs using digitalWrite().
Use the following pins to access them:
BTN1 – PIN_BTN1, pin 48, RG6
BTN2 – PIN_BTN2, pin 49, RG7
BTN3 – PIN_BTN3, pin 50, RA0
LD1 – PIN_LED1, pin 51, RG12
LD2 – PIN_LED2, pin 52, RG13
LD3 – PIN_LED3, pin 53, RG14
LD4 – PIN_LED4, pin 54, RG15
5V Signal Compatibility
The PIC32 microcontroller operates at 3.3V.
And the I/O pins provide 3.3V logic levels. It is
possible, in some circumstances, to use the
Cerebot MX7cK to operate with 5V logic
devices however.
There are two issues to consider when dealing
with 5V compatibility for 3.3V logic. The first is
protection of 3.3V inputs from damage caused
by 5V signals. The second is whether the 3.3V
output is high enough to be recognized as a
logic high value by a 5V input.
page 9 of 36
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Cerebot MX7cK Reference Manual
The digital only I/O pins on the PIC32
microcontroller are 5V tolerant. It is safe to
apply 5V logic signals directly to these pins
without risk of damage to the microcontroller.
with pins that are not 5V tolerant on the PIC32
microcontroller.
The analog capable I/O pins on the PIC32 are
not 5V tolerant. The absolute maximum
voltage rating for the analog pins is 3.6V.
Generally, the analog pins are the pins on I/O
port B, however, there are other non-5V
tolerant pins on the device.
A reset button is at the upper right corner of
the board. Pressing this button will reset the
PIC32 microcontroller.
RESET
Refer to the PIC32MX5XX/6XX/7XX Family
Data Sheet for more information about which
pins on the device are 5V tolerant before
applying input signals higher than 3.3V to any
pin on the Cerebot MX7cK board.
If a 5V signal is applied to a non-5V tolerant
pin, some external means must be used to limit
the applied voltage to 3.6V or less. The
Cerebot MX7cK board provides 200 ohm
series resistors between the microcontroller
pins and the Pmod connector pins. These
resistors are primarily intended to provide short
circuit protection on the outputs, but will also
provide limited protection if a 5V signal is
inadvertently applied to a non-5V tolerant pin.
One technique that can be used to limit an
input voltage to a safe level is to use a 200
ohm series resistor and Shottky diode
connected to the 3.3V supply to clamp the
voltage.
The minimum output high voltage of the PIC32
microcontroller is rated at 2.4V when sourcing
12mA of current. When driving a high
impedance input (typical of CMOS logic) the
output high voltage will be close to 3.3V. Some
5V devices will recognize this voltage as a
logic high input, and some won’t. Many 5V
logic inputs will work reliably with 3.3V inputs.
If the 3.3V logic output is not sufficient for 5V
logic input to be reliably seen as a logic high
input signal, some external means must be
used to raise the output level. In some cases, a
pull-up resistor to 5V is sufficient. A pull-up
resistor in the range of 2Kohm–10kOhm can
be used. This technique should not be used
www.digilentinc.com
page 10 of 36
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Cerebot MX7cK Reference Manual
PIC32 Peripheral Devices
The following describes the peripheral devices
available in the PIC32MX795F512L
microcontroller and how they are accessed on
the Cerebot MX7cK board.
CPU Clock Source
The PIC32 microcontroller supports numerous
clock source options for the main processor
operating clock. The Cerebot MX7cK board is
designed to operate with either a silicon
resonator from Discera, IC2, for use with the
EC oscillator option, or an external crystal, X1,
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
EC 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 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 #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
www.digilentinc.com
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 #pragma
config FPBDIV. The PBCLK divider can be
set to divide by 1, 2, 4, or 8.
The following example will set up the Cerebot
MX7cK for operation with a SYSCLK frequency
of 80Mhz and a PBCLK frequency of 10Mhz:
#pragma
#pragma
#pragma
#pragma
#pragma
#pragma
config
config
config
config
config
config
FNOSC = PRIPLL
POSCMOD = EC
FPLLIDIV = DIV_2
FPLLMUL = MUL_20
FPLLODIV = DIV_1
FPBDIV = DIV_8
Documentation for the PIC32 configuration
variables can be found in the PIC32MX
Configuration Settings guide. This is found
using the “Help.Topics…” command in the
MPLAB IDE. Also, refer to Appendix C for an
example of setting the configuration variables.
When using the Cerebot MX7cK with the
chipKIT MPIDE software, the clock source is
set by the boot loader and no action is
required.
Ethernet Interface
The Cerebot MX7cK 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 PIC32
microcontroller, the Cerebot MX7cK board
provides an SMSC LAN8720 Ethernet Physical
page 11 of 36
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Cerebot MX7cK Reference Manual
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.
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. Each
PIC32MX795 device is programmed at the
factory to have a unique MAC address that will
be loaded by default when the device is reset.
Digilent provides another unique MAC address
that can be used as well. This address is
printed on a sticker attached to the bottom of
the board. The Digilent provided MAC 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
www.digilentinc.com
for the PIC32MX795 and LAN8720, plus
network protocol documentation, for operation
of the Ethernet interface.
Digilent has Network libraries available that
can be used to develop both client and server
applications when using the board with the
chipKIT MPIDE development environment.
These libraries are built on a custom version of
the Microchip Applications Library network
stack and support various network protocols
such as TCP, UDP, DHCP and others to
provide complete Ethernet network support.
These libraries can be downloaded from the
Cerebot MX7cK product page on the Digilent
web site.
The Digilent chipKIT libraries contain examples
illustrating various network applications.
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
MX7cK is designed to use the standard (not
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 chipKIT MPIDE boot loader sets these
configuration variables, and so no action is
necessary when using the MPIDE software
system.
The LAN8720 PHY has a reset signal, labeled
NRST in the schematic, used to reset the PHY.
This signal is connected to the TRCLK/RA6 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
page 12 of 36
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Cerebot MX7cK Reference Manual
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.
The Digilent chipKIT network libraries perform
this automatically, and so no action is
necessary when using the board with the
MPIDE software system and the Digilent
libraries.
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 MX7cK
provides an 8Mhz clock to the PIC32
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 #pragma
config statement. The following statements
must be used to configure the PIC32
microcontroller for use of the USB controller:
#pragma config UPLLEN = ON
#pragma config UPLLIDIV = DIV_2
www.digilentinc.com
When using the chipKIT MPIDE development
environment, these will have been set by the
boot loader, so no action is needed.
When operating as a USB device, the Cerebot
MX7cK 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 “EXT” position of J3. To
operate as a bus powered device, the shorting
block should be placed in the USB Device
position, “USB”, on J3.
Note that when operating as a bus powered
device, the Cerebot MX7cK and all devices
connected to it are limited to using no more
than 500mA of current to remain in compliance
with the USB specification.
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
MX7cK 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, “EXT”
position of J3. The power supply used must be
a regulated 5V supply. The Cerebot MX7cK
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 MX7cK
board and/or the USB device being used.
Connector J20, on the top of the board in the
lower right corner is the USB host connector.
This is a standard USB type A receptacle. USB
devices may be connected either directly or
through a standard USB cable.
Jumper JP10 is used to route power to the
host connector being used. Place the shorting
page 13 of 36
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Cerebot MX7cK 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.
the chipKIT MPIDE development environment.
These libraries are built on a custom version of
the Microchip Applications Library and can be
downloaded from the Cerebot MX7cK product
page on the Digilent web site.
When operating as a USB host, the
PIC32MX795 microcontroller controls
application of power to the connected device
via the VBUSON control pin. The VBUSON
signal is connected to the circuit net labeled
P32_VBUSON in the schematic. Bus power is
applied to the attached USB 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 Digilent chipKIT libraries contain examples
illustrating various USB host and device
applications.
CAN Interface
The Controller Area Network (CAN) 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 VBUSON pin drives the enable input of a
Texas Instruments TPS2051B Current-Limited
Power Distribution Switch to control the
application of USB power to the host
connector. This switch has over-current
detection capability and provides an overcurrent fault indication by pulling the signal
P32_USBOC low. The over-current output
indication can be monitored via I/O Port D pin
13 (RD13) on the PIC32MX795
microcontroller. This pin can function as
change notification pin 19 (CN19), so that a
change notification interrupt can be used to
detect the overcurrent condition.
The PIC32MX795 microcontroller contains two
independent CAN network controllers. These
CAN controllers in combination with two
Microchip MCP2551 CAN transceivers allow
the Cerebot MX7cK board to operate on up to
two independent CAN networks. Refer to the
PIC32MX5XX/6XX/7XX Family Data Sheet
and the PIC32 Family Reference Manual,
Section 34, Controller Area Network (CAN),
plus CAN network documentation for
information on operation of the CAN controllers
and CAN networking in general.
Details about the operation of the TPS2051B
can be obtained from the data sheet available
at the Texas Instruments web site.
The Microchip C32 peripheral library, plib,
provides basic support for all CAN operations
using the CAN controllers in the PIC32MX795
microcontroller.
The Microchip Applications Library, MAL,
available on the Microchip web site contains
USB driver code for implementing either USB
host devices or USB function devices. This
library contains numerous examples
demonstrating both device and host operation
of PIC32 microcontrollers. With minor
modification or configuration, these reference
designs are suitable to use for developing USB
firmware for the Cerebot MX7cK board.
Digilent has USB libraries available that can be
used to develop both USB device and USB
host applications when using the board with
www.digilentinc.com
Digilent has a basic CAN library available for
use with the chipKIT MPIDE software
environment. This library can be downloaded
from the Cerebot MX7cK product page on the
Digilent web site.
The PIC32MX795 microcontroller provides two
sets of pins that can be used to connect the
CAN controllers to the external transceivers.
The Cerebot MX7cK 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
page 14 of 36
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Cerebot MX7cK Reference Manual
interface pins, the following statement must
appear in the main program module:
#pragma config FCANIO=OFF
The chipKIT MPIDE boot loader sets the
configuration variables, and so no action is
necessary when using the MPIDE software
system.
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 the UART2 and SPI4 ports.
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. In some cases it
may be possible to use UART2 at the same
time as CAN1 as the RX and TX pins are not
used by the CAN interface (only RTS and CTS
are used). When JP1 and JP2 are in the CAN
position Pmod pins JF-01 and JF-04 are not
connected to the PIC32 microcontroller.
There is no standard connector for use with
CAN networks. The Cerebot MX7cK 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
Cerebot MX7cK schematic, Sheet 6, for
information on the connectors and signal
assignments. 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
MX7cK 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
www.digilentinc.com
MX7cK provides termination resistors and
jumpers to enable/disable them depending on
the location of the board in the network.
Jumper JP5 is used to 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 it.
UART Interface
The PIC32MX795 microcontroller can provide
up to six UARTs. Due to conflicting uses of
many of the pins used by the UARTs, the
Cerebot MX7cK is designed to allow use of two
of them: UART1 and UART2. The UARTs can
provide either a 2-wire or a 4-wire
asynchronous serial interface. The 2-wire
interface provides receive (RX) and transmit
(TX) pins. The 4-wire interface includes
request-to-send (RTS) and clear-to-send
(CTS) in addition to receive and transmit.
UART1 can be accessed from Pmod connector
JE and UART2 can be accessed from Pmod
connector JF using the following pins:
U1CTS
U1TX
U1RX
U1RTS
JE-01
JE-02
JE-03
JE-04
U2CTS
U2TX
U2RX
U2RTS
JF-01
JF-02
JF-03
JF-04
Note that early versions of the Microchip
PIC32MX5XX/6XX/7XX Family Data Sheet
refer to UART1 as UART1A and UART2 as
UART3A.
Detailed information about the operation of the
UART peripherals can be found in the PIC32
Family Reference Manual, Section 21, UART.
The USB Serial converter is connected to
UART1. The MPIDE uses this to communicate
page 15 of 36
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Cerebot MX7cK Reference Manual
with the boot loader. This can also be used for
a serial communications interface between the
Cerebot MX7cK board and other software
running on a PC. Resistors are used to
decouple the USB serial interface and so
UART1 can also be used via Pmod connector
JE when not using it to communicate with the
USB serial converter.
the slave, it simultaneously receives a byte
from the slave.
Note that when using the MPIDE software,
devices connected to JE can interfere with the
operation of the serial interface and prevent
the MPIDE from successfully downloading
sketches to the board. If this happens,
disconnect the external device from JE until
the sketch has been downloaded and then
reconnect it.
The following gives the mapping between SPI
signals and connector pins:
When using the Cerebot MX7cK with the
MPIDE and the chipKIT system, the UARTs
are accessed using the HardwareSerial facility
built into the system. UART1, Pmod connector
JE, is accessed using the Serial object and
UART2, Pmod connector JF, is accessed
using Serial1.
Serial Peripheral Interface (SPI)
SPI is a four wire synchronous serial interface
and SPI devices can operate as either master
devices or as slave device. The PIC32
microcontroller labels the four SPI signals as
Slave Select (SS), Serial Data Out (SDO),
Serial Data In (SDI), and Serial Clock (SCK). A
master device transmits SS, SDO and SCK,
and receives SDI. A slave device receives SS,
SDI, and SCK and transmits SDO. The SS
signal is used to enable the slave device, and
this signal is only significant for slave devices.
A master device can use any general purpose
I/O pin to generate SS to enable the slave.
An SPI transaction begins with the master
device bringing SS low. When the slave sees
SS go low it becomes enabled and waits for
the master to send data. The master shifts
data out on SDO and simultaneously shifts
data in on SDI. The slave device receives data
from the master on its SDI pin and
simultaneously sends data to the master on its
SDO pin. Each time the master sends a byte to
www.digilentinc.com
The PIC32MX795 microcontroller provides four
Serial Peripheral Interfaces. The Cerebot
MX7cK supports use of three ports: SPI1, SPI3
and SPI4. These are accessed using Pmod
connectors JD, JE, and JF.
SS1
SDO1
SDI1
SCK1
JD-01
JD-02
JD-03
JD-04
SS3
SDO3
SDI3
SCK3
JE-01
JE-02
JE-03
JE-04
SS4
SDO4
SDI4
SCK4
JF-01
JF-02
JF-03
JF-04
Note that early versions of the Microchip
PIC32MX5Xx/6XX/7XX Family Data Sheet
refer to SPI3 as SPI1A and SPI4 as SPI3A.
Detailed information about the operation of the
SPI peripherals can be found in the PIC32
Family Reference Manual, Section 23, Serial
Peripheral Interface.
When using the Cerebot MX7cK with the
MPIDE and the chipKIT system, the SPI ports
are accessed using either the standard chipKIT
SPI library or using the Digilent DSPI library.
The standard SPI library supports access to a
single SPI port, SPI4, Pmod connector JF. This
is accessed using the SPI object.
The DSPI library supports access to all three
SPI ports. The DSPI0 object class is used to
create an object used to access SPI1, Pmod
connector JD. The DSPI1 object class is used
to access SPI3, Pmod connector JE, and the
page 16 of 36
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Cerebot MX7cK Reference Manual
DSPI2 object class is used to access SPI4,
Pmod connector JF.
lines low. One device on the I2C bus must
provide the pull-up resistors.
I2C™ Interface
On the Cerebot MX7cK, I2C2, connector J8,
has permanently connected, 2.2K ohm, pull-up
resistors. I2C1, connector J7, provides
selectable pull-ups that can be enabled or
disabled via jumper blocks JP3 and JP4. The
pull-ups are enabled by installing shorting
blocks on JP3 and JP4. They are disabled by
removing the shorting blocks. Only one device
on the bus should have the pull-ups enabled.
The I2C daisy chain connectors, J7 and J8,
each provide 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 MX7cK boards or other I2Ccapable 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
www.digilentinc.com
Pull-ups
Enabled
3V3
GND
SDA
SCL
3V3
In addition to I2C1 and I2C2, two other I2C
interfaces, I2C3 and I2C5 can be accessed via
pins on Pmod connectors. I2C3 can be
accessed via Pmod connector JE, pins JE-02
(SCL3) and JE-03 (SDA3). I2C5 can be
accessed via Pmod connector JF, pins JF-02
(SCL5) and JF-03 (SDA5)
GND
The pull-ups on I2C1 on the Cerebot MX7cK
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.
SCL
The PIC32MX795 microcontroller provides for
up to five independent I2C interfaces. The
Cerebot MX7cK is designed to provide
dedicated access to two of these interfaces
I2C1 and I2C2 via I2C daisy chain connectors
J7 and J8. Connector J7 provides access to
I2C1 while connector J8 provides access to
I2C2.
If the I2C interfaces on Pmod connectors JE or
JF are being used, external pull-up resistors
must be provided. These resistors can be in
the range 1K ohm to 10K ohm, and should be
connected to pull the pins to 3.3V.
SDA
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 PIC32MX5XX/6XX/7XX
Family Data Sheet and the PIC32 Family
Reference Manual, Section 24, Inter-Integrated
Circuit, for detailed information on configuring
and using the I2C interface.
Pull-ups
Disabled
Jumper Settings for I2C Pull-Up Resistors
When using the Cerebot MX7cK with the
MPIDE and the chipKIT system, the I2C
interfaces are accessed using the standard
chipKIT Wire library, or the Digilent DTWI
library.
page 17 of 36
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Cerebot MX7cK Reference Manual
The Wire library supports a single I2C interface,
I2C2 on J8. This is accessed using the Wire
object.
The DTWI library supports four I2C interfaces.
The DTWI0 object class is used to create an
object for access to I2C1, connector J7, and
the DTWI1 object class is used to access I2C2,
connector J8. The DTWI2 object class is used
to access I2C3, Pmod connector JE, and the
DTWI3 object class is used to access I2C5,
Pmod connector JF.
The pinouts of the I2C connectors are as
follows:
Connector J7 – I2C1
J7-1, J7-2 – SCL1
J7-3, J7-4 – SDA1
J7-5, J7-6 – GND
J7-7, J7-8 – VCC3V3
Connector J8 – I2C2
J8-1, J8-2 – SCL2
J8-3, J8-4 – SDA2
J8-5, J8-6 – GND
J8-7, J8-8 – VCC3V3
Pmod connector JE – I2C3
JE-02 – SCL3
JE-03 – SDA3
Pmod connector JF – I2C5
JF-02 – SCL5
JF-03 – SDA5
On-Board I2C Peripheral Device
The Cerebot MX7cK provides one on-board
I2C peripheral device, a Microchip 24LC256
serial EEPROM. This device is connected to
I2C2. The 24LC256 is a 256Kbit (32Kbyte)
serial EEPROM device to provide non-volatile
memory storage. The device address for the
24LC256 is 1010000 (0x50).
When using the chipKIT MPIDE software, this
device can be accessed using the Wire library
Wire object, or using the DTWI library via the
DTWI1 object class.
www.digilentinc.com
Refer to the Microchip data sheet for detailed
information on the operation of this device.
Analog Inputs
The PIC32MX795 microcontroller provides a
10-bit analog to digital (A/D) converter that
provides up to sixteen analog inputs. The
Cerebot MX7cK board provides access to 10
of these inputs via the Pmod connectors. The
converted values produced by the A/D
converter will be in the range 0–1023.
For detailed information on the operation and
use of the A/D converter, refer to the PIC32
Family Reference Manual, Section 17, 10-bit
AD Converter.
The analog inputs are accessed using the
analogRead() function in the chipKIT MPIDE
software. The analog input pin number is
specified using the symbols A0–A9. The digital
pin numbers for the pins or the numbers 0–9
can also be used, but using the symbols A0–
A9 is recommended.
The following gives the Pmod connector
position, digital pin number, and
microcontroller I/O port and bit number for the
analog inputs:
A0 – JA-01, digital pin 0, RB02
A1 – JA-02, digital pin 1, RB03
A2 – JA-03, digital pin 2, RB04
A3 – JA-04, digital pin 3, RB06
A4 – JA-07, digital pin 4, RB07
A5 – JA-08, digital pin 5, RB08
A6 – JA-09, digital pin 6, RB09
A7 – JA-10, digital pin 7, RB10
A8 – JC-07, digital pin 20, RB15
A9 – JC-10, digital pin 23, RB14
A/D Converter Voltage Reference
The PIC32 microcontroller provides two
voltage reference inputs to the analog to digital
converter. Vref- is used set the lower reference
level and Vref+ is used to set the upper
reference level. These references can be
page 18 of 36
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Cerebot MX7cK Reference Manual
connected to internal references or to external
references using two of the analog input pins.
When the internal references are being used,
Vref- is connected to VSS and Vref+ is
connected to VDD. This means that the
voltage input range at the analog input pins is
0V–3.3V. In this case, an input voltage of 0V
will convert to ~0, an input voltage of 1.65V will
convert to ~511, and an input voltage of 3.3V
will convert to ~1023.
Either one, or both, of the references can be
connected to external reference pins. When
this is done, the references can be set to
voltages other than 0V and 3.3V.
If, for example, both references were selected
to use external references, with 1V applied to
Vref- and 2V applied to Vref+, the input voltage
range at the analog input pins would be from
1V to 2V. An applied voltage of 1V would have
a converted value of ~0, 1.5V would have a
converted value of ~511, and 2V would have a
converted value of ~1023.
When both external references are being used,
Vref+ must have a higher voltage applied to in
than Vref-.
The analog reference input pins appear on
Pmod connector JE, pins 9 & 10. Vref- is on
pin JE-09, and Vref+ is on pin JE-10. These
pins are not available to be used for digital I/O
when being used as an external reference.
When using the chipKIT MPIDE software, the
use of external analog references is selected
using the analogReference() function. The
following values can be used with
analogReference():
DEFAULT – Vref- = 0V, Vref+ = 3.3V
INTERNAL – same as default
EXTERNAL – Vref- = 0V, Vref+ = voltage
at A2
EXTMINUS – Vref- = voltage at A3, Vref+ =
3.3V
EXTPLUSMINUS – Vref- = voltage at A3,
Vref+ = voltage at A2
www.digilentinc.com
Timers
The PIC32MX795 microcontroller provides five
timers that can be used for various timing
functions. These timers are each 16 bits wide,
although two pairs, TIMER2/TIMER3 and
TIMER4/TIMER5 can be combined to produce
32 bit wide timers.
A timer consists of a control register, a counter
register, and a period register. The control
register is used to configure the timer for
various modes of operation. The count register
counts cycles of the clock source selected via
the control register. This clock source can be
the peripheral bus clock or a division of the
peripheral bus clock via a pre-scaler divider.
The period register can be used to generate an
interrupt and/or reset the count register when a
pre-determined value is reached.
Each timer has an associated input pin. In
some operating modes, this pin can be used
as an external clock input to the timer, or as a
gate input to turn on/off incrementing of the
counter register under control of an external
signal.
The following gives the Pmod connector
position, chipKIT pin number, and
microcontroller I/O port and bit number for the
timer input pins.
T1CK – not available
T2CK – JC-01, digital pin 16, RC01
T3CK – not available
T4CK – not available
T5CK – JD-03, digital pin 26, RC04
For detailed information on the operation of the
PIC32 timers, refer to the PIC32 Family
Reference Manual, Section 14, Timers.
When using the chipKIT MPIDE software, the
symbols PIN_TCK2 and PIN_TCK5 can be
used to access the timer input pins.
Control and operation of the timers is not
explicitly provided in the current version of the
chipKIT MPIDE software. This capability will be
added in a future version of the software.
page 19 of 36
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Cerebot MX7cK Reference Manual
Timers are used implicitly by various core
functions and libraries, however.
OC4 – JD-09, digital pin 30, RD03
OC5 – JC-09, digital pin 22, RD04
Output Compare
Input Capture
The PIC32MX795 microcontroller provides five
output compare units that can be used to
control the timing of state changes on certain
output pins or to generate pulse width
modulated (PWM) outputs.
The PIC32MX795 microcontroller provides five
input capture units. The design of the Cerebot
MX7cK board allows the use of three of them.
Each output compare unit works with a
particular output pin (OC1-OC5). It can be
programmed to control the pin in any of the
following ways:
PWM output
Generate continuous pulses
Generate a single pulse
Toggle the output pin
Generate falling edge
Generate rising edge
The output compare units work in conjunction
with a timer. Either Timer2 or Timer3 can be
used with any of the five output compare units.
Refer to the PIC32 Family Reference Manual,
Section 16, Output Compare for detailed
information on the use of the output compares
units.
When using the chipKIT MPIDE software,
these are accessed using the analogWrite()
function. The digital pin number, or preferably,
the symbols PIN_OC1 through PIN_OC5 are
used to specify the pin. The chipKIT MPIDE
software currently only supports using the
output compare units to generate PWM
outputs. It uses Timer2 to control the output
compares.
The following gives Pmod connector position,
chipKIT pin number, and microcontroller I/O
port and bit number for the output compare
unit’s output pins:
OC1 – JD-02, digital pin 25, RD00
OC2 – JD-07, digital pin 28, RD01
OC3 – JD-08, digital pin 29, RD02
www.digilentinc.com
An input capture unit works in conjunction with
a timer and monitors the state of an associated
pin. When the pin changes state, the current
value of the timer is captured. The input
capture units can be used with either Timer2 or
Timer3.
The input capture unit can be programmed to
be sensitive to either a rising edge, a falling
edge, or both edges on the input pin. An
interrupt can also be signaled when an input
capture is triggered. Each input capture has a
four level deep FIFO that can buffer up to four
capture events.
For detailed information on the operation and
use of the input capture units, refer to the
PIC32 Family Reference Manual, Section 15,
Input Capture.
The following gives the Pmod connector
position, chipKIT pin number, and
microcontroller port and bit number for the
input capture units input pins:
IC1 – not available
IC2 – JD-01, digital pin 24, RD09
IC3 – JD-04, digital pin 27, RD10
IC4 – not available
IC5 – JD-10, digital pin 31, RD12
When using the chipKIT MPIDE software, the
symbols PIN_IC2, PIN_IC3, and PIN_IC5 can
be used to access the capture input pins.
Use of the input capture units is not currently
supported in the chipKIT MPIDE software. This
will be added in a future version.
page 20 of 36
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Cerebot MX7cK Reference Manual
External Interrupts
Citizen CFS206-32.768KDZF-UB is a crystal
part that can be used in this location.
The PIC32 microcontroller provides five
external interrupt inputs. An external interrupt
input can be used to generate an interrupt to
the microprocessor CPU when the pin changes
state. They can be programmed to interrupt on
a rising edge or a falling edge on the pin.
Refer to the PIC32 Family Reference Manual,
Section 8, Interrupts for more information on
the operation of the external interrupts.
These are accessed using the attachInterrupt()
and detachInterrupt() functions when using the
chipKIT MPIDE software. The interrupt number
is specified using the numbers 0-4, or
preferably, the symbols EXT_INT0 through
EXT_INT4. The symbols PIN_INT0 through
PIN_INT4 are also defined to refer to the digital
pin numbers used for the external interrupt
inputs.
The following gives connector position, chipKIT
pin number, and microcontroller I/O port and
bit number. Note that INT0-INT1 are on Pmod
connectors. INT3 and INT4 are on I2C1 daisy
chain connector J7. When using these pins as
external interrupt inputs, they are not available
to use for I2C. It may also be necessary to
disable the pull-ups by pulling the shorting
blocks from JP3 or JP4.
INT0 – JD-02, digital pin 25, RD00
INT1 – JE-07, digital pin 36, RE08
INT2 – JF-07, digital pin 44, RE09
INT3 – J7-1 & J7-2, digital pin 57, RA14
INT4 – J7-3 & J7-4, digital pin 58, RA15
RTCC
The PIC32 microcontroller contains a low
frequency oscillator and Real Time
Clock/Calendar circuit, RTCC, that can be
used to maintain time and date information.
The operation of the RTCC requires a
32.768Khz frequency source. The crystal X2
position, just above and on the right of the
PIC32 microcontroller, IC1, is provided for the
user to solder in a 32Khz watch crystal. The
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page 21 of 36
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Cerebot MX7cK Reference Manual
Appendix A: Connector Descriptions and Jumper Settings
Label
JA-JF
Function
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. These connectors
can be used for general access to I/O pins on the PIC32MX795 microcontroller.
JPA –
JPF
Pmod header power select
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.
J1
USB Serial converter auxiliary signals
This connector can be used to access the auxiliary RS232 handshaking signals not used on
the Cerebot MX4cK board.
J2
USB Serial converter (UART) connector
This USB micro-AB connector is used to connect the FT232R serial converter to a USB port
on the user PC.
J3
Power supply source select
This jumper is used to select the source of main board power.
Place the shorting block in the, “USB” position to have the board powered from the USB
device connector, J19.
Place the shorting block in the, “EXT” position to have the board powered from one of the
external power connectors, J17 or J18.
Place the shorting block in the, “DBG” position to have the board powered from the debug
USB connector, J15.
Place the shorting block in the “UART” position to have the board powered from the USB
serial converter connector, J2
J7
I2C1 daisy chain connector
This connector provides access to the I2C signals, power and ground for I2C1.
J8
I2C2 daisy chain connector
This connector provides access to the I2C signals, power and ground for I2C2.
J9
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
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page 22 of 36
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Cerebot MX7cK Reference Manual
This connector provides access to the 10/100 Ethernet port.
J12J14
J15
Do Not Use.
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.
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 I2C1
These two jumpers are used to enable/disable the pull-up resistors on I2C1. 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.
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.
www.digilentinc.com
page 23 of 36
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Cerebot MX7cK Reference Manual
JP8
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.
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.
JP11
USB Serial converter reset disconnect
This is used to connect/disconnect the USB serial converter reset circuit from the PIC32
MCLR pin. The shorting block must be in place on this jumper when using the chipKIT
MPIDE development tools. Remove the shorting block if the USB serial converter is
interfering with proper operation of the licensed debugger circuit.
JP17
Do Not Use
www.digilentinc.com
page 24 of 36
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Cerebot MX7cK Reference Manual
Appendix B: Example of Configuration Values
The following example illustrates setting the configuration values in the PIC32 microcontroller on the
Cerebot MX7cK. 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 MX7cK 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
#pragma config POSCMOD
#pragma config FPLLIDIV
#pragma config FPLLMUL
#pragma config FPLLODIV
#pragma config FPBDIV
#pragma config FSOSCEN
=
=
=
=
=
=
=
PRIPLL
EC
DIV_2
MUL_20
DIV_1
DIV_8
OFF
//
//
//
//
//
//
//
Oscillator selection
Primary oscillator mode
PLL input divider
PLL multiplier
PLL output divider
Peripheral bus clock divider
Secondary oscillator enable
/* Clock control settings
*/
#pragma config IESO
= OFF
#pragma config FCKSM
= CSDCMD
#pragma config OSCIOFNC = OFF
// Internal/external clock switchover
// Clock switching (CSx)/Clock monitor (CMx)
// Clock output on OSCO pin enable
/* USB Settings
*/
#pragma config UPLLEN
= ON
#pragma config UPLLIDIV = DIV_2
#pragma config FVBUSONIO = OFF
#pragma config FUSBIDIO = OFF
//
//
//
//
USB PLL enable
USB PLL input divider
VBUS pin control
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
*/
#pragma
#pragma
#pragma
Protection settings
config CP
config BWP
config PWP
/* Debug settings
*/
#pragma config ICESEL
www.digilentinc.com
= OFF
= OFF
= OFF
// Code protection
// Boot flash write protect
// Program flash write protect
= ICS_PGx1
// ICE pin selection
page 25 of 36
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Cerebot MX7cK Reference Manual
Appendix C: Connector and Jumper Block Pinout Tables
Arranged by Microcontroller Pin Number
PIC32
Pin #
Connector
Pin
chipKIT
Pin #
MCU
Port Bit
PIC32 Signal Name
Notes
1
3
4
5
6
7
8
9
LD4
JB-08
JB-09
JB-10
JC-01
N/A
N/A
JD-03
54
13
14
15
16
N/A
N/A
26
RG15
RE05
RE06
RE07
RC01
RC02
RC03
RC04
AERXERR/RG15
PMD5/RE5
PMD6/RE6
PMD7/RE7
T2CK/RC1
T3CK/AC2TX/RC2
T4CK/AC2RX/RC3
T5CK/SDI1/RC4
LED4
10
11
12
14
17
18
19
20
21
22
BTN1
BTN2
N/A
N/A
BTN3
JE-07
JF-07
N/A
JA-03
JA-02
48
49
N/A
N/A
50
36
44
59
2
1
RG06
RG07
RG08
RG09
RA00
RE08
RE09
RB05
RB04
RB03
.../SCK2A/U2BTX/U2ARTS/PMA5/CN8/RG6
.../SDA2A/SDI2A/U2ARX/PMA4/CN9/RG7
.../SCL2A/SDO2A/U2ATX/PMA3/CN10/RG8
.../SS2A/U2BRX/U2ACTS/PMA2/CN11/RG9
TMS/RA0
AERXD0/INT1/RE8
AERXD1/INT2/RE9
AN5/C1IN+/VBUSON/CN7/RB5
AN4/C1IN-/CN6/RB4
AN3/C2IN+/CN5/RB3
BTN1
BTN2
Ethernet PHY
Ethernet PHY
BTN3
23
24
25
26
27
28
29
32
33
34
JA-01
N/A
N/A
JA-04
JA-07
JE-09
JE-10
JA-08
JA-09
JA-10
0
N/A
N/A
3
4
38
39
5
6
7
RB02
RB01
RB00
RB06
RB07
RA09
RA10
RB08
RB09
RB10
AN2/C2IN-/CN4/RB2
PGEC1/AN1/CN3/RB1
PGED1/AN0/CN2/RB0
PGEC2/AN6/OCFA/RB6
PGED2/AN7/RB7
Vref-/CVref-/AERXD2/PMA7/RA9
Vref+/CVref+/AERXD3/PMA6/RA10
AN8/C1OUT/RB8
AN9/C2OUT/RB9
CVrefout/PMA13/AN10/RB10
35
38
39
40
41
42
43
44
47
48
N/A
JF-08
JF-04
JF-01
N/A
N/A
JC-10
JC-07
JE-01
JE-04
N/A
45
43
40
N/A
N/A
23
20
32
35
RB11
RA01
RF13
RF12
RB12
RB13
RB14
RB15
RD14
RD15
AN11/ERXERR/AETXERR/PMA12/RB11
TCK/RA1
AC1TX/SCK3A/U3BTX/U3ARTS/RF13
AC1RX/SS3A/U3BRX/U3ACTS/RF12
AN12/ERXD0/AECRS/PMA11/RB12
AN13/ERXD1/AECOL/PMA10/RB13
AN14/ERXD2/AETXD3/PMALH/PMA1/RB14
AN15/.../OCFB/PMALL/PMA0/CN12/RB15
AETXD0/SS1A/U1BRX/U1ACTS/CN20/RD14
AETXD1/SCK1A/U1BTX/U1ARTS/CN21/RD15
www.digilentinc.com
CAN2
CAN2
USB VBUSON
debug PGD
debug PGC
Ethernet PHY
also CAN1 (JP-2)
also CAN1 (JP-1)
Ethernet PHY
Ethernet PHY
page 26 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
49
50
51
JF-03
JF-02
N/A
42
41
N/A
RF04
RF05
RF03
SDA3A/SDI3A/U3ARX/PMA9/CN17/RF4
SCL3A/SDO3A/U3ATX/PMA8/CN18/RF5
USBID/RF3
52
53
56
57
58
59
60
61
63
64
JE-03
JE-02
N/A
N/A
J7-1,J7-2
J7-3,J7-4
JF-09
JF-10
N/A
N/A
34
33
N/A
N/A
55
56
46
47
N/A
N/A
RF02
RF08
RG03
RG02
RA02
RA03
RA04
RA05
RC12
RC15
SDA1A/SDI1A/U1ARX/RF2
SCL1A/SDO1A/U1ATX/RF8
D-/RG3
D+/RG2
SCL2/RA2
SDA2/RA3
TDI/RA4
TDO/RA5
OSC1/CLKI/RC12
OSC2/CLKO/RC15
66
67
68
69
70
71
72
73
74
76
J8-1,J8-2
J8-3.J8-4
N/A
JD-01
JD-04
N/A
JD-02
N/A
N/A
JD-07
57
58
N/A
24
27
N/A
25
N/A
N/A
28
RA14
RA15
RD08
RD09
RD10
RD11
RD00
RC13
RC14
RD01
AETXCLK/SCL1/INT3/RA14
AETXEN/SDA1/INT4/RA15
RTCC/EMDIO/AEMDIO/IC1/RD8
SS1/IC2/RD9
SCK1/IC3/PMCS2/PMA15/RD10
EMDC/AEMDC/IC4/PMCS1/PMA14/RD11
SDO1/OC1/INT0/RD0
SOSCI/CN1/RC13
SOSCO/T1CK/CN0/RC14
OC2/RD1
77
78
79
JD-08
JD-09
JD-10
29
30
31
RD02
RD03
RD12
OC3/RD2
OC4/RD3
ETXD2/IC5/PMD12/RD12
80
81
N/A
JC-09
60
22
RD13
RD04
ETXD3/PMD13/CN19/RD13
OC5/PMWR/CN13/RD4
82
83
84
87
88
89
90
91
92
93
JC-08
N/A
JC-04
N/A
N/A
JC-03
JC-02
N/A
JE-08
JB-01
21
N/A
19
N/A
N/A
18
17
N/A
37
8
RD05
RD06
RD07
RF00
RF01
RG01
RG00
RA06
RA07
RE00
PMRD/CN14/RD5
ETXEN/PMD14/CN15/RD6
ETXCLK/PMD15/CN16/RD7
C1RX/ETXD1/PMD11/RF0
C1TX/ETXD0/PMD10/RF1
C2TX/ETXERR/PMD9/RG1
C2RX/PMD8/RG0
TRCLK/RA6
TRD3/RA7
PMD0/RE0
94
95
96
97
JB-02
LD3
LD1
LD2
9
53
51
52
RE01
RG14
RG12
RG13
PMD1/RE1
TRD2/RG14
TRD1/RG12
TRD0/RG13
www.digilentinc.com
USBID (USB-4)
D- (USB-2)
D+ (USB-3)
I2C2
I2C2
Primary Oscillator
Primary Oscillator
I2C1
I2C1
Ethernet PHY
Ethernet PHY
Secondary Oscillator
Secondary Oscillator
USB Overcurrent
detect
Ethernet PHY
Ethernet PHY
Ethernet PHY
Ethernet PHY Reset
LED3
LED1
LED2
page 27 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
98
99
100
JB-03
JB-04
JB-07
www.digilentinc.com
10
11
12
RE02
RE03
RE04
PMD2/RE2
PMD3/RE3
PMD4/RE4
page 28 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
Arranged by Connector Pin Number and Digital Pin Number
PIC32
Pin #
Connector
Pin
chipKIT
Pin #
MCU
Port
Bit
Signal
23
22
21
26
JA-01
JA-02
JA-03
JA-04
0
1
2
3
RB02
RB03
RB04
RB06
AN2/C2IN-/CN4/RB2
AN3/C2IN+/CN5/RB3
AN4/C1IN-/CN6/RB4
PGEC2/AN6/OCFA/RB6
27
32
JA-07
JA-08
4
5
RB07
RB08
PGED2/AN7/RB7
AN8/C1OUT/RB8
33
34
JA-09
JA-10
6
7
RB09
RB10
AN9/C2OUT/RB9
CVrefout/PMA13/AN10/RB10
93
94
98
99
JB-01
JB-02
JB-03
JB-04
8
9
10
11
RE00
RE01
RE02
RE03
PMD0/RE0
PMD1/RE1
PMD2/RE2
PMD3/RE3
100
3
JB-07
JB-08
12
13
RE04
RE05
PMD4/RE4
PMD5/RE5
4
5
6
90
89
84
JB-09
JB-10
JC-01
JC-02
JC-03
JC-04
14
15
16
17
18
19
RE06
RE07
RC01
RG00
RG01
RD07
PMD6/RE6
PMD7/RE7
T2CK/RC1
C2RX/PMD8/RG0
C2TX/ETXERR/PMD9/RG1
ETXCLK/PMD15/CN16/RD7
44
82
JC-07
JC-08
20
21
RB15
RD05
AN15/.../OCFB/PMALL/PMA0/CN12/RB15
PMRD/CN14/RD5
81
43
JC-09
JC-10
22
23
RD04
RB14
OC5/PMWR/CN13/RD4
AN14/ERXD2/AETXD3/PMALH/PMA1/RB14
69
72
9
70
76
77
JD-01
JD-02
JD-03
JD-04
JD-07
JD-08
24
25
26
27
28
29
RD09
RD00
RC04
RD10
RD01
RD02
SS1/IC2/RD9
SDO1/OC1/INT0/RD0
T5CK/SDI1/RC4
SCK1/IC3/PMCS2/PMA15/RD10
OC2/RD1
OC3/RD2
78
79
47
53
52
48
18
92
28
JD-09
JD-10
JE-01
JE-02
JE-03
JE-04
JE-07
JE-08
JE-09
30
31
32
33
34
35
36
37
38
RD03
RD12
RD14
RF08
RF02
RD15
RE08
RA07
RA09
OC4/RD3
ETXD2/IC5/PMD12/RD12
AETXD0/SS1A/U1BRX/U1ACTS/CN20/RD14
SCL1A/SDO1A/U1ATX/RF8
SDA1A/SDI1A/U1ARX/RF2
AETXD1/SCK1A/U1BTX/U1ARTS/CN21/RD15
AERXD0/INT1/RE8
TRD3/RA7
Vref-/CVref-/AERXD2/PMA7/RA9
www.digilentinc.com
Notes
page 29 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
29
40
50
JE-10
JF-01
JF-02
39
40
41
RA10
RF12
RF05
Vref+/CVref+/AERXD3/PMA6/RA10
AC1RX/SS3A/U3BRX/U3ACTS/RF12
SCL3A/SDO3A/U3ATX/PMA8/CN18/RF5
49
39
19
38
60
61
10
11
17
96
JF-03
JF-04
JF-07
JF-08
JF-09
JF-10
BTN1
BTN2
BTN3
LD1
42
43
44
45
46
47
48
49
50
51
RF04
RF13
RE09
RA01
RA04
RA05
RG06
RG07
RA00
RG12
SDA3A/SDI3A/U3ARX/PMA9/CN17/RF4
AC1TX/SCK3A/U3BTX/U3ARTS/RF13
AERXD1/INT2/RE9
TCK/RA1
TDI/RA4
TDO/RA5
.../SCK2A/U2BTX/U2ARTS/PMA5/CN8/RG6
.../SDA2A/SDI2A/U2ARX/PMA4/CN9/RG7
TMS/RA0
TRD1/RG12
97
95
1
58
59
66
67
20
LD2
LD3
LD4
J7-1,J7-2
J7-3,J7-4
J8-1,J8-2
J8-3.J8-4
N/A
52
53
54
55
56
57
58
59
RG13
RG14
RG15
RA02
RA03
RA14
RA15
RB05
TRD0/RG13
TRD2/RG14
AERXERR/RG15
SCL2/RA2
SDA2/RA3
AETXCLK/SCL1/INT3/RA14
AETXEN/SDA1/INT4/RA15
AN5/C1IN+/VBUSON/CN7/RB5
80
N/A
60
RD13
ETXD3/PMD13/CN19/RD13
LED2
LED3
LED4
I2C2
I2C2
I2C1
I2C1
USB VBUSON
USB Overcurrent
detect
91
25
24
35
41
42
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
RA06
RB00
RB01
RB11
RB12
RB13
TRCLK/RA6
PGED1/AN0/CN2/RB0
PGEC1/AN1/CN3/RB1
AN11/ERXERR/AETXERR/PMA12/RB11
AN12/ERXD0/AECRS/PMA11/RB12
AN13/ERXD1/AECOL/PMA10/RB13
Ethernet PHY Reset
debug PGC
debug PGD
Ethernet PHY
Ethernet PHY
Ethernet PHY
7
8
63
73
74
64
83
68
71
87
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
RC02
RC03
RC12
RC13
RC14
RC15
RD06
RD08
RD11
RF00
T3CK/AC2TX/RC2
T4CK/AC2RX/RC3
OSC1/CLKI/RC12
SOSCI/CN1/RC13
SOSCO/T1CK/CN0/RC14
OSC2/CLKO/RC15
ETXEN/PMD14/CN15/RD6
RTCC/EMDIO/AEMDIO/IC1/RD8
EMDC/AEMDC/IC4/PMCS1/PMA14/RD11
C1RX/ETXD1/PMD11/RF0
CAN2
CAN2
Primary Oscillator
Secondary Oscillator
Secondary Oscillator
Primary Oscillator
Ethernet PHY
Ethernet PHY
Ethernet PHY
Ethernet PHY
88
51
57
56
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
RF01
RF03
RG02
RG03
C1TX/ETXD0/PMD10/RF1
USBID/RF3
D+/RG2
D-/RG3
Ethernet PHY
USBID (USB-4)
D+ (USB-3)
D- (USB-2)
www.digilentinc.com
also CAN1 (JP-1)
also CAN1 (JP-2)
BTN1
BTN2
BTN3
LED1
page 30 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
12
14
N/A
N/A
www.digilentinc.com
N/A
N/A
RG08
RG09
.../SCL2A/SDO2A/U2ATX/PMA3/CN10/RG8
.../SS2A/U2BRX/U2ACTS/PMA2/CN11/RG9
Ethernet PHY
Ethernet PHY
page 31 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
Arranged by Microcontroller I/O Port Name and Bit Number
PIC32
Pin #
Connector
Pin
chipKIT
Pin #
MCU
Port
Bit
PIC32 Signal Name
Notes
17
BTN3
50
RA00
TMS/RA0
BTN3
38
58
JF-08
J7-1,J7-2
45
55
RA01
RA02
TCK/RA1
SCL2/RA2
I2C2
59
60
61
91
92
28
J7-3,J7-4
JF-09
JF-10
N/A
JE-08
JE-09
56
46
47
N/A
37
38
RA03
RA04
RA05
RA06
RA07
RA09
SDA2/RA3
TDI/RA4
TDO/RA5
TRCLK/RA6
TRD3/RA7
Vref-/CVref-/AERXD2/PMA7/RA9
29
66
67
25
24
23
JE-10
J8-1,J8-2
J8-3.J8-4
N/A
N/A
JA-01
39
57
58
N/A
N/A
0
RA10
RA14
RA15
RB00
RB01
RB02
Vref+/CVref+/AERXD3/PMA6/RA10
AETXCLK/SCL1/INT3/RA14
AETXEN/SDA1/INT4/RA15
PGED1/AN0/CN2/RB0
PGEC1/AN1/CN3/RB1
AN2/C2IN-/CN4/RB2
22
21
JA-02
JA-03
1
2
RB03
RB04
AN3/C2IN+/CN5/RB3
AN4/C1IN-/CN6/RB4
20
26
N/A
JA-04
59
3
RB05
RB06
AN5/C1IN+/VBUSON/CN7/RB5
PGEC2/AN6/OCFA/RB6
27
32
33
34
35
41
JA-07
JA-08
JA-09
JA-10
N/A
N/A
4
5
6
7
N/A
N/A
RB07
RB08
RB09
RB10
RB11
RB12
PGED2/AN7/RB7
AN8/C1OUT/RB8
AN9/C2OUT/RB9
CVrefout/PMA13/AN10/RB10
AN11/ERXERR/AETXERR/PMA12/RB11
AN12/ERXD0/AECRS/PMA11/RB12
42
43
44
6
7
8
9
63
73
74
N/A
JC-10
JC-07
JC-01
N/A
N/A
JD-03
N/A
N/A
N/A
N/A
23
20
16
N/A
N/A
26
N/A
N/A
N/A
RB13
RB14
RB15
RC01
RC02
RC03
RC04
RC12
RC13
RC14
AN13/ERXD1/AECOL/PMA10/RB13
AN14/ERXD2/AETXD3/PMALH/PMA1/RB14
AN15/.../OCFB/PMALL/PMA0/CN12/RB15
T2CK/RC1
T3CK/AC2TX/RC2
T4CK/AC2RX/RC3
T5CK/SDI1/RC4
OSC1/CLKI/RC12
SOSCI/CN1/RC13
SOSCO/T1CK/CN0/RC14
Ethernet PHY
64
72
76
77
N/A
JD-02
JD-07
JD-08
N/A
25
28
29
RC15
RD00
RD01
RD02
OSC2/CLKO/RC15
SDO1/OC1/INT0/RD0
OC2/RD1
OC3/RD2
Primary Oscillator
www.digilentinc.com
I2C2
Ethernet PHY Reset
I2C1
I2C1
debug PGC
debug PGD
USB VBUSON
Ethernet PHY
Ethernet PHY
CAN2
CAN2
Primary Oscillator
Secondary Oscillator
Secondary Oscillator
page 32 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
78
81
82
JD-09
JC-09
JC-08
30
22
21
RD03
RD04
RD05
OC4/RD3
OC5/PMWR/CN13/RD4
PMRD/CN14/RD5
83
84
68
69
70
71
79
N/A
JC-04
N/A
JD-01
JD-04
N/A
JD-10
N/A
19
N/A
24
27
N/A
31
RD06
RD07
RD08
RD09
RD10
RD11
RD12
ETXEN/PMD14/CN15/RD6
ETXCLK/PMD15/CN16/RD7
RTCC/EMDIO/AEMDIO/IC1/RD8
SS1/IC2/RD9
SCK1/IC3/PMCS2/PMA15/RD10
EMDC/AEMDC/IC4/PMCS1/PMA14/RD11
ETXD2/IC5/PMD12/RD12
80
47
N/A
JE-01
60
32
RD13
RD14
ETXD3/PMD13/CN19/RD13
AETXD0/SS1A/U1BRX/U1ACTS/CN20/RD14
48
93
94
98
99
100
3
4
5
18
JE-04
JB-01
JB-02
JB-03
JB-04
JB-07
JB-08
JB-09
JB-10
JE-07
35
8
9
10
11
12
13
14
15
36
RD15
RE00
RE01
RE02
RE03
RE04
RE05
RE06
RE07
RE08
AETXD1/SCK1A/U1BTX/U1ARTS/CN21/RD15
PMD0/RE0
PMD1/RE1
PMD2/RE2
PMD3/RE3
PMD4/RE4
PMD5/RE5
PMD6/RE6
PMD7/RE7
AERXD0/INT1/RE8
19
87
88
52
51
49
JF-07
N/A
N/A
JE-03
N/A
JF-03
44
N/A
N/A
34
N/A
42
RE09
RF00
RF01
RF02
RF03
RF04
AERXD1/INT2/RE9
C1RX/ETXD1/PMD11/RF0
C1TX/ETXD0/PMD10/RF1
SDA1A/SDI1A/U1ARX/RF2
USBID/RF3
SDA3A/SDI3A/U3ARX/PMA9/CN17/RF4
50
53
40
39
90
89
57
56
10
11
JF-02
JE-02
JF-01
JF-04
JC-02
JC-03
N/A
N/A
BTN1
BTN2
41
33
40
43
17
18
N/A
N/A
48
49
RF05
RF08
RF12
RF13
RG00
RG01
RG02
RG03
RG06
RG07
SCL3A/SDO3A/U3ATX/PMA8/CN18/RF5
SCL1A/SDO1A/U1ATX/RF8
AC1RX/SS3A/U3BRX/U3ACTS/RF12
AC1TX/SCK3A/U3BTX/U3ARTS/RF13
C2RX/PMD8/RG0
C2TX/ETXERR/PMD9/RG1
D+/RG2
D-/RG3
.../SCK2A/U2BTX/U2ARTS/PMA5/CN8/RG6
.../SDA2A/SDI2A/U2ARX/PMA4/CN9/RG7
12
14
96
97
N/A
N/A
LD1
LD2
N/A
N/A
51
52
RG08
RG09
RG12
RG13
.../SCL2A/SDO2A/U2ATX/PMA3/CN10/RG8
.../SS2A/U2BRX/U2ACTS/PMA2/CN11/RG9
TRD1/RG12
TRD0/RG13
www.digilentinc.com
Ethernet PHY
Ethernet PHY
Ethernet PHY
USB Overcurrent
detect
Ethernet PHY
Ethernet PHY
USBID (USB-4)
also CAN1 (JP-1)
also CAN1 (JP-2)
D+ (USB-3)
D- (USB-2)
BTN1
BTN2
Ethernet PHY
Ethernet PHY
LED1
LED2
page 33 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
95
1
LD3
LD4
www.digilentinc.com
53
54
RG14
RG15
TRD2/RG14
AERXERR/RG15
LED3
LED4
page 34 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
Declaration of Conformity
In accordance with EN ISO/IEC 17050-1:2010
Manufacturers Name:
Manufacturers Address:
Application of Council Directives:
EMC
Standards:
EMC
Digilent, Inc.
1300 NE Henley Court
Pullman, WA 99163
U.S.A.
2004/108/EC
EN55022:2010
EN55024:2010
Product Name:
Cerebot MX7cK
Product Model Number:
Digilent Product Category:
Digilent P/N 210-223
Large Form Factor Microcontroller Boards
We, the undersigned, hereby declare that the equipment specified above conforms to the
above Directives and Standards.
Location:
Date:
_Pullman, WA______
_August 23, 2012 ___
www.digilentinc.com
Signature:
__________
Full Name (print): Clint Cole
page 35 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Cerebot MX7cK Reference Manual
Title:
www.digilentinc.com
President___________
page 36 of 36
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
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