Pmod interface (peripheral module interface) is an open standard defined by Digilent in the Pmod Interface Specification for connecting peripheral modules to FPGA and microcontroller development boards using 12 (8 I/O, 2 VCC, 2 GND) pins. Pmod or Pmods may also refer to modules compatible with the Pmod interface.

Overview

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

Pmod type pinouts
type1 (7)2 (8)3 (9)4 (10)5 (11)6 (12)
Type 1 (GPIO)GPIO1GPIO2/PWMGPIO3GPIO4GNDVcc
Type 1A (extended GPIO)GPIO1 GPIO5GPIO2/PWM GPIO6/PWMGPIO3 GPIO7GPIO4 GPIO8GND GNDVcc Vcc
Type 2 (SPI)CSMOSIMISOSCKGNDVcc
Type 2A (extended SPI)CS1 GPIO/INTMOSI GPIO/RESETMISO GPIO/CS2SCK GPIO/CS3GND GNDVcc Vcc
Type 3 (UART)CTS/GPIOTxDRxDRTS/GPIOGNDVcc
Type 3A (extended UART)CTS/GPIO GPIO/INTTxD GPIO/RESETRxD GPIORTS/GPIO GPIOGND GNDVcc Vcc
Type 4 (H-bridge)DIRENSenseASenseBGNDVcc
Type 5 (dual H-bridge)DIR1EN1DIR2EN2GNDVcc
Type 5A (extended dual H-bridge)DIR1 DIR2EN1 EN2Sense1A Sense2ASense1B Sense2BGND GNDVcc Vcc
Type 6 (I2C)nc/INTnc/RESETSCLSDAGNDVcc
Type 6A (extended I2C)nc/INT GPIOnc/RESET GPIOSCL GPIOSDA GPIOGND GNDVcc Vcc
Type 7 (I2S)LRCLK GPIODACdata GPIOADCdata MCLKBCLK GPIOGND GNDVcc 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

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

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

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

History of Pmod specification
YearVersionNotesRefs
20111.0.0First release
20171.1.0.
20171.2.0.
20201.3.0.
20201.3.1Current release

See also

  • Asynchronous serial bus such as RS-232 and RS-422.
  • UEXT, a similar "Universal EXTension" connector format also for UART, I2C, and SPI, although separately over 10 wires in a 2x5 layout.
  • * CRUVI FPGA Card FPGA daughter card standard of Standardization Group for Embedded Technologies e.V. (SGET) with Pmod option

External links

  • - Digilent
  • - YouTube