Digilent MX4cK - Manual (Page 8)

Cerebot MX4cK Reference Manual
www.digilentinc.com page 8 of 35
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Pmod™ Connectors
The Cerebot MX4cK has nine connectors for
connecting Digilent Pmod peripheral modules.
The Pmod connectors, labeled JA–JF and JH–
JK, are 2x8 right-angle, female pin header
connectors. Each connector has an associated
power select jumper block labeled JPA–JPF
and JPH–JPK.
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: six-
pin 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 MX4cK are twelve
pin connectors.
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.
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 six-
pin 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 pin on the Pmod connector. They are
switchable between either the unregulated
power supply, BRD_VU, or the 3.3V main
board supply, BRD_3V3. Place the shorting
block in the 3V3 position for regulated 3.3V
and in the VU position to use the unregulated
supply.
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.
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 MX4cK or attached via cables.
Digilent has a variety of Pmod interconnect
cables available.
See the Pinout Tables in Appendix C, for more
information about connecting peripheral
modules and other devices to the Cerebot
MX4cK. These tables describe the mapping
between pins on the PIC32MX460
microcontroller and the pins on the various
connectors.