Digilent MX3cK - Manual (Page 15)

Cerebot MX3cK Reference Manual
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• OC1 – JC-09, digital pin 23, RD0
• OC2 – JC-10, digital pin 24, RD1
• OC3 – JD-02, digital pin 25, RD2
• OC4 – JD-08, digital pin 29, RD3
• OC5 – JB-09, digital pin 14, RD4
Input Capture
The PIC32 microcontroller provides five input
capture units. 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 – JE-07, digital pin 32, RD08
• IC2 – JB-01, digital pin 8, RD09
• IC3 – JD-03, digital pin 26, RD10
• IC4 – JD-09, digital pin 30, RD11
• IC5 – JB-09, digital pin 14, RD04
Use of the input capture units is not currently
supported in the chipKIT MPIDE software. This
will be added in a future version.
External Interrupts
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 following gives Pmod connector position,
chipKIT pin number, and microcontroller I/O
port and bit number:
• INT0 – JB-04, digital pin 11, RF6
• INT1 – JE-07, digital pin 36, RD8
• INT2 – JB-01, digital pin 8, RD9
• INT3 – JD-03, digital pin 26, RD10
• INT4 – JD-09, digital pin 30, RD11
RTCC
The PIC32 microcontroller contains a low
frequency oscillator and Real Time
Clock/Calendar, RTCC, circuit 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 left of the
PIC32 microcontroller, IC5, is provided for the
user to solder in a 32Khz watch crystal. The
Citizen CFS206-32.768KDZF-UB is a crystal
part that can be used in this location.