chipKIT™ Pmod Shield-Uno™ Reference Manual

Revision: February 8, 2013

Note: This document applies to REV A of the board.


The chipKIT Pmod Shield-Uno is an input/output expansion board for use with the chipKIT Uno32™ and chipKIT uC32™. It provides the additional circuitry and connectors to allow Digilent peripheral modules (Pmods™) to be used with the Uno32 and uC32.

The Pmod Shield-Uno has five 2×6 Digilent Pmod connectors. It also provides access to the I/O connectors available on the Uno32 as well as connecting to the I2C bus supported by the Uno32 and uC32. The Pmod Shield-Uno has the same form factor as the Uno32 and uC32 boards.

Features include:

  • Five 2.6 Digilent Pmod connectors.
  • One 6-pin header connector for SPI.
  • One I2C daisy chain connector.
  • Four user LEDs.
  • Standard chipKIT Shield connectors.

1. Functional Description

The Pmod Shield-Uno is designed to be used with the chipKIT Uno32 board. When used in combination, the two boards provide the necessary supporting hardware and connectors to make use of most Digilent PmodsTM. The rest of this document will only reference the Uno32, however, the shield can also be used with the chipKIT uC32.

The Pmod Shield-Uno has the following connectors:

J1 & J3: Digital Signal Pass-Through Connectors This connector provides most of the signals used by the Uno32 board to the Pmod Shield-Uno board. The remaining signals are passed through the Pmod Shield-Uno.

J6: SPI #2 Connector This connector provides access to the SPI signals MISO, MOSI, SCK, and SS.

JA-JE: Digilent Pmod Connectors These connectors provide access to the signals of the Uno32 in a form factor which readily allows Digilent Pmods to be connected.

J2: I2C #1 Daisy Chain Connector This is a 2×4 pin header connector that provides access to the I2C signals SDA and SCL as well as power from the 3.3V power bus and ground. This can be used to extend the I2C bus off of the board and to power external I2C devices. Digilent has cables and a selection of I2C peripheral modules that can be accessed using this connector.

J4: Analog Signal Pass-Through Connector This connector passes the analog input pins on the Uno32 through the Pmod Shield-Uno board.

J5: Power Pass-Through Connector This connector passes the power connector from the Uno32 through the Pmod Shield-Uno board, and powers the Pmod Shield-Uno from the Uno32.

2. I2C Busses and Connectors

The Inter-Integrated Circuit (I2C) 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 PIC32MX3XX data sheet and the PIC32 Family Reference Manual for detailed information on configuring and using the I2C interface.

The PIC32MX320 microcontroller on the Uno32 provides for two independent I2C interfaces. The Pmod Shield-Uno is designed to provide access to both of these interfaces I2C #1 (SCL1, SDA1) and I2C #2 (SCL2, SDA2). I2C #1 is the bus accessed through the standard chipKIT Wire library. Connector J2 provides access to I2C port #1 while access to I2C port #2 is available on several of the connectors of the Pmod Shield-Uno.

Connector J2 can be used to extend the I2C busses off of the board to connect to external I2C devices. This is a standard 2×4 pin header connector with 0.100” spaced pins. It provides access to the I2C signals, SCL and SDA, plus VCC3V3 and ground. The VCC3V3 can be used to power external I2C devices.

The I2C bus uses open collector drivers to allow multiple devices to drive the bus signals. This means that pull-up resistors must be provided to supply the logic high state for the signals. The Pmod Shield-Uno provides 2.2Kohm pull-up resistors on I2C #1.

Generally, only one set of pull-ups are used on the bus. Jumpers JP10 and JP11 can be used to disable the on-board pull-ups on I2C #1 if a different value is needed or some other device on the bus is providing the pull-ups or if I2C #1 isn’t being used and the pull-ups are interfering with the use of the pins. The on-board pull-ups are enabled by install shorting blocks on JP10 and JP11. Removing the shorting blocks disables the pull-ups. Digilent has several small I/O modules available that can be connected using the I2C connector. These include a 3-axis accelerometer, 4-channel, 12-bit A/D converter, serial character LCD panel, 3-axis gyroscope, real-time clock/calendar, and an I/O expander.

3. SPI Connector

The SPI connector pins are as follows: Pin 1 (MISO), Pin 3 (SCK), Pin 4 (MOSI), and Pin 5 (SS). These signals also appear on connector J8 of the Uno32. Jumpers JP5 and JP7 on the Uno32 are used to select whether the Uno32 operates as a Master (transmit on MOSI, receive on MISO) or a Slave (transmit on MISO, receive on MOSI) device. The shorting blocks on JP5 and JP7 are normally placed in the Master position for the Uno32 to function as an SPI master. Also, jumper JP4 on the Uno32 is used to select PWM output (in RD4 position) or the SPI SS function on Pin 5 (in RG9 position).

CHIPKIT and the CHIPKIT Logo are trademarks or registered trademarks of Microchip Technology Incorporated in the U.S. and other countries, and are used under license.

Appendix: chipKIT Pmod Shield-Uno Pinout Tables

J1 Pins

Uno32 Pin # PIC32 Pin # Pin Signal Notes
8 44 J1-01 IC3/PMCS2/PMA15/INT3/RD10
34 53 J1-02 PMRD/CN14/RD5
9 51 J1-03 OC4/RD3
35 45 J1-04 IC4/PMCS1/PMA14/INT4/RD11
10 8 J1-05 SS2/PMA2/CN11/RG9 selected by JP4
10 52 J1-05 PMWR/OC5/IC5/CN13/RD4 selected by JP4
36 54 J1-06 CN15/RD6
11 6 J1-07 or J1-09 SDO2/PMA3/CN10/RG8 selected by JP5/JP7
37 55 J1-08 CN16/RD7
12 5 J1-09 or J1-07 SDI2/PMA5/CN8/RG7 selected by JP7/JP5
38 35 J1-10 U1RTS/BCLK1/SCK1/INT0/RF6
13 4 J1-11 SCK2/PMA5/CN8/RG6
39 31 J1-12 PMA9/U2RX/SDA2/CN17/RF4
40 32 J1-14 PMA8/U2TX/SCL2/CN18/RF5
42 16 J1-15 PGED1/PMA6/AN0/VREF+/CVREF+/CN2/RB0
41 15 J1-16 PGC1/AN1/VREF-/CVREF-/CN3/RB1

J3 Pins

Uno32 Pin # PIC32 Pin # Pin Signal Notes
0 34 J3-01 U1RX/SDI1/RF2
26 60 J3-02 PMD0/RE0
1 33 J3-03 U1TX/SDO1/RF3
27 61 J3-04 PMD1/RE1
2 42 J3-05 IC1/RTCC/INT1/RD8 selected by JP4
28 62 J3-06 PMD2/RE2 selected by JP4
3 46 J3-07 OC1/RD0
29 63 J3-08 PMD3/RE3 selected by JP5/JP7
4 59 J3-09 RF1
30 64 J3-10 PMD4/RE4 selected by JP7/JP5
5 49 J3-11 OC2/RD1
31 1 J3-12 PMD5/RE5
6 50 J3-13 OC3/RD2
32 2 J3-14 PMD6/RE6
7 43 J3-15 IC2/U1CTS/INT2/RD9
33 3 J3-16 PMD7/RE7

JA Pins

Uno32 Pin # PIC32 Pin # Pin Signal Notes
26 60 JA-01 PMD0/RE0
27 61 JA-02 PMD1/RE1
28 62 JA-03 PMD2/RE2
29 63 JA-04 PMD3/RE3
JA-06 VCC 3V3 / 5V0 select with JPA
30 64 JA-07 PMD4/RE4
31 1 JA-08 PMD5/RE5
32 2 JA-09 PMD6/RE6
33 3 JA-10 PMD7/RE7
JA-12 VCC 3V3 / 5V0 select with JPA

JB Pins

Uno32 Pin # PIC32 Pin # Pin Signal Notes
7 43 JB-01 U1CTS/IC2/INT2/RD9
1 33 JB-02 U1TX/SDO1/RF3
0 34 JB-03 U1RX/SDI1/RF2
38 35 JB-04 U1RTS/SCK1/INT0/RF6
JB-06 VCC 3V3 / 5V0 select with JPB
36 54 JB-07 CN15/RD6
34 53 JB-08 PMRD/CN14/RD5
10 52 JB-09 PMWR/OC5/IC5/CN13/RD4
37 55 JB-10 CN16/RD7
JB-12 VCC 3V3 / 5V0 select with JPB

J2 Pins (I2C)

Uno32 Pin # PIC32 Pin # Pin Signal Notes
37 J2-01 SCL1/RG2
37 J2-02 SCL1/RG2
36 J2-03 SDA1/RG3
36 J2-04 SDA1/RG3
J2-05 GND
J2-06 GND
J2-07 VDD
J2-08 VDD

J4 Pins

Uno32 Pin # PIC32 Pin # Pin Signal Notes
A00/14 14 J4-01 C2IN-/AN2/SS1/CN4/RB2
A06/20 13 J4-02 C2IN+/AN3/CN5/RB3
A01/15 11 J4-03 C1IN-/AN4/CN6/RB4
A07/21 12 J4-04 C1IN+/AN5/CN7/RB5
A02/16 21 J4-05 U2CTS/C1OUT/AN8/RB8
A08/22 22 J4-06 PMA7/C2OUT/AN9/RB9
A03/17 23 J4-07 TMS/CVREFOUT/PMA13/AN10/RB10
A09/23 24 J4-08 TDO/PMA12/AN11/RB11
A04/18 27 J4-09 TCK/PMA11/AN12/RB12 selected by JP6
36 J4-09 SDA1/RG3 selected by JP6
A10/24 28 J4-10 TDI/PMA10/AN13/RB13
A05/19 29 J4-11 PMALH/PMA1/U2RTS/AN14/RB14 selected by JP8
37 J4-11 SCL1/RG2 selected by JP8
A11/25 30 J4-12 PMALL/PMA0/AN15/OCFB/CN12/RB15

JC Pins

Uno32 Pin # PIC32 Pin# Pin Signal Notes
10 8 JC-01 SS2/PMA2/CN11/RG9 selected by JP4
6 JC-02 MOSI
5 JC-03 MISO
13 4 JC-04 SCK2/PMA5/CN8/RG6
JC-06 VCC 3V3 / 5V0 select with JPC
2 42 JC-07 IC1/RTCC/INT1/RD8
A07/21 12 JC-08 C1IN+/AN5/CN7/RB5
A01/15 11 JC-09 C1IN-/AN4/CN6/RB4
A06/20 13 JC-10 C2IN+/AN3/CN5/RB3
JC-12 VCC 3V3 / 5V0 select with JPC

JD Pins

Uno32 Pin # PIC32 Pin # Pin Signal Notes
A02/16 21 JD-01 U2CTS/C1OUT/AN8/RB8
40 32 JD-02 PMA8/U2TX/SCL2/CN18/RF5
39 31 JD-03 PMA9/U2RX/SDA2/CN17/RF4
A05/19 29 JD-04 PMALH/PMA1/U2RTS/AN14/RB14
JD-06 VCC 3V3 / 5V0 select with JPD
42 15 JD-08 PGC1/AN1/VREF-/CVREF-/CN3/RB1
3 46 JD-09 OC1/RD0
5 49 JD-10 OC2/RD1
JD-12 VCC 3V3 / 5V0 select with JPD

JE Pins

Uno32 Pin # PIC32 Pin # Pin Signal Notes
A00/14 14 JE-01 C2IN-/AN2/SS1/CN4/RB2
6 50 JE-02 OC3/RD2
8 44 JE-03 IC3/PMCS2/PMA15/INT3/RD10
A08/22 22 JE-04 PMA7/C2OUT/AN9/RB9
JE-06 VCC 3V3 / 5V0 select with JPD
A04/18 27 JE-07 TCK/PMA11/AN12/RB12
9 51 JE-08 OC4/RD3
35 45 JE-09 IC4/PMCS1/PMA14/INT4/RD11
A10/24 28 JE-10 TDI/PMA10/AN13/RB13
JE-12 VCC 3V3 / 5V0 select with JPD

J6 Pins (SPI)

Uno32 Pin # PIC32 Pin # Pin Signal Notes
5 5 JE-01 MISO
JE-02 Unconnected
13 4 JE-03 SCK2/PMA5/CN8/RG6
6 6 JE-04 MOSI
10 8 JE-05 SS2/PMA2/CN11/RG9 selected by JP4