Digilent chipKIT Uno32 Reference Manual - Page 9

Browse online or download pdf Reference Manual for Microcontrollers Digilent chipKIT Uno32. Digilent chipKIT Uno32 18 pages.

Print Page

chipKIT Uno32 Reference Manual

The digital I/O pins on the PIC32

microcontroller are 5V tolerant. The analog

capable I/O pins are not 5V tolerant. To

provide 5V tolerance on those pins, the Uno32

contains clamp diodes and current limiting

resistors to protect them from 5V input

voltages.

The fact that all I/O pins are 5V tolerant means

that it is safe to apply 5V logic levels to any

pins on the board without risk of damaging the

PIC32 microcontroller.

The minimum high-voltage output 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 devices will work reliably with 3.3V inputs.

Input/Output Connections

The Uno32 board provides 42 of the I/O pins

from the PIC32 microcontroller to pins on the

input/output connectors J5, J6, and J7.

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 voltage range (V

the pin current must be restricted to +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 I/O pin is 5.5V. For more

detailed specifications, refer to the

PIC32MX3XX/4XX Data Sheet available from

the Microchip web site.

Connectors J5 and J6 are 2x8 female pin

header connectors that provide digital I/O

signals. The outer row of pins (closer to the

board edge) corresponds to the I/O connector

pins on an Arduino Uno or Duemilanove board.

The inner row of pins provides access to the

extra I/O signals provided by the PIC32

microcontroller.

www.digilentinc.com

0.4V, V

2.4V)

Connector J7 is a 2x6 female pin header

connector that provides access to the analog

input pins on the microcontroller. The outer row

of pins corresponds to the six analog pins on

an Arduino Uno or Duemilanove. The inner row

of pins are the additional I/O signals provided

by the PIC32 microcontroller. The analog pins

on J7 can also be used as digital I/O pins.

The chipKIT/Arduino system uses logical pin

numbers to identify digital I/O pins on the

connectors. The logical pin numbers for the I/O

pins on the Uno32 are 0-43. These pin

numbers are labeled in the silk screen on the

board.

Pin numbers 0-13 are the outer row of pins on

J6 and J5, from right to left. Pin numbers 14-19

are the outer row of pins on J7 from left to

right. Pins 20-25 are the inner row of pins on

J7 from left to right. Pin numbers 26-41 are the

inner row of pins on J6 and J5 from right to left.

Pin 42 is the pin labeled A on J5. This pin is

normally the reference voltage for the

microcontroller's A/D converter, but can also

be used as a digital I/O pin.

In addition to the connector pin, Pin 13 also

connects to the user LED LD4. Pin 43

connects to user LED LD5. Pin 43 pin does not

go to any connector.

The analog inputs on connector J7 are

assigned pin numbers. The outer row of pins

on J7 are analog inputs A0-A5. The inner row

of pins are A6-A11. These pins are also

assigned digital pin numbers: A0-A5 are digital

pins 14-19, and A6-A11 are 20-25.

Peripheral I/O Functions

The PIC32 microcontroller on the Uno32 board

provides a number of peripheral functions. The

following peripherals are provided:

UART port 1: Asynchronous serial port. Pin 0

(RX), Pin 1 (TX). These pins are connected to

I/O connector J6 and are also connected to the

FT232R USB serial converter. It is possible to

use these pins to connect to an external serial

page 9 of 17