Pmod interface (peripheral module interface) is an open standard defined by Digilent in the Pmod Interface Specification[1] for connecting peripheral modules to FPGA and microcontroller development boards using 6 pins. Pmod or Pmods may also refer to modules compatible with the Pmod interface.

Overview

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Pmods are available from simple push buttons to more complex modules with network interfaces, analog to digital converters or liquid-crystal displays. These modules can be used with a variety of FPGA or microcontroller development boards from different vendors. The Pmod interface is designed so Pmods can be quickly connected to host boards for prototyping or evaluation purposes without soldering, but Pmods aren't quite plug and play since software and configuration is required.

Pmods come with a standard 6-pin interface of 4 signals, one ground and one power pin. Double and quad Pmods also exist. These duplicate the standard interface to allow more signals to pass through to the module.

Pmods can use either SPI, I2C or UART protocol. With I2C it is possible to use a 4-pin connector. Alternatively the pins 1 to 4 can be used as simple digital I/O pins.

Pinouts

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Pmod type pinouts
type 1
(7)
2
(8)
3
(9)
4
(10)
5
(11)
6
(12)
Type 1 (GPIO) GPIO1 GPIO2/PWM GPIO3 GPIO4 GND Vcc
Type 1A (extended GPIO) GPIO1
GPIO5
GPIO2/PWM
GPIO6/PWM
GPIO3
GPIO7
GPIO4
GPIO8
GND
GND
Vcc
Vcc
Type 2 (SPI) CS MOSI MISO SCK GND Vcc
Type 2A (extended SPI) CS1
GPIO/INT
MOSI
GPIO/RESET
MISO
GPIO/CS2
SCK
GPIO/CS3
GND
GND
Vcc
Vcc
Type 3 (UART) CTS/GPIO TxD RxD RTS/GPIO GND Vcc
Type 3A (extended UART) CTS/GPIO
GPIO/INT
TxD
GPIO/RESET
RxD
GPIO
RTS/GPIO
GPIO
GND
GND
Vcc
Vcc
Type 4 (H-bridge) DIR EN SenseA SenseB GND Vcc
Type 5 (dual H-bridge) DIR1 EN1 DIR2 EN2 GND Vcc
Type 5A (extended dual H-bridge) DIR1
DIR2
EN1
EN2
Sense1A
Sense2A
Sense1B
Sense2B
GND
GND
Vcc
Vcc
Type 6 (I2C) nc/INT nc/RESET SCL SDA GND Vcc
Type 6A (extended I2C) nc/INT
GPIO
nc/RESET
GPIO
SCL
GPIO
SDA
GPIO
GND
GND
Vcc
Vcc
Type 7 (I2S) LRCLK
GPIO
DACdata
GPIO
ADCdata
MCLK
BCLK
GPIO
GND
GND
Vcc
Vcc
  • I2C/UART/SPI:
    • INT - interrupt, slave to master, open-collector, active low
    • RESET - reset signal, master to slave, active low
  • SPI:
    • CS - chipselect, active low
  • H-bridge
    • EN - enable, active high, can be used with PWM
    • SenseA/SenseB - input from quadrature encoder for speed and direction

History

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Digilent was founded in 2000 by two Washington State University electrical engineering professors.[2]

In 2011, v1.0.0 of Pmod Interface Specification was released.[3]

In January 2013, National Instruments acquired all outstanding shares of Digilent Inc., which became a wholly owned subsidiary.[4]

History of Pmod specification
Year Version Notes Refs
2011 1.0.0 First release [3]
2017 1.1.0 . [5]
2017 1.2.0 . [6]
2020 1.3.0 . [7]
2020 1.3.1 Current release [1]

See also

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References

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  1. ^ a b Pmod specification v1.3.1; Digilent; October 2020.
  2. ^ Maxfield, Max (6 February 2020). "Big Things in Store for Digilent in 2020". embedded-computing.com. OpenSystems Media. Retrieved 21 September 2020.
  3. ^ a b Pmod specification v1.0.0; Digilent; November 2011.
  4. ^ "National Instruments acquires Digilent Inc". dangerousprototypes.com. Dangerous Prototypes self-published blog. 24 January 2013. Retrieved 21 September 2020.
  5. ^ Pmod specification v1.1.0; Digilent; July 2017.
  6. ^ Pmod specification v1.2.0; Digilent; October 2017.
  7. ^ Pmod specification v1.3.0; Digilent; September 2020.
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