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 6 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| 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) | GPIO1GPIO5 | GPIO2/PWMGPIO6/PWM | GPIO3GPIO7 | GPIO4GPIO8 | GNDGND | VccVcc |
| Type 2 (SPI) | CS | MOSI | MISO | SCK | GND | Vcc |
| Type 2A (extended SPI) | CS1GPIO/INT | MOSIGPIO/RESET | MISOGPIO/CS2 | SCKGPIO/CS3 | GNDGND | VccVcc |
| Type 3 (UART) | CTS/GPIO | TxD | RxD | RTS/GPIO | GND | Vcc |
| Type 3A (extended UART) | CTS/GPIOGPIO/INT | TxDGPIO/RESET | RxDGPIO | RTS/GPIOGPIO | GNDGND | VccVcc |
| 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) | DIR1DIR2 | EN1EN2 | Sense1ASense2A | Sense1BSense2B | GNDGND | VccVcc |
| Type 6 (I2C) | nc/INT | nc/RESET | SCL | SDA | GND | Vcc |
| Type 6A (extended I2C) | nc/INTGPIO | nc/RESETGPIO | SCLGPIO | SDAGPIO | GNDGND | VccVcc |
| Type 7 (I2S) | LRCLKGPIO | DACdataGPIO | ADCdataMCLK | BCLKGPIO | GNDGND | VccVcc |
- 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.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 | 5 |
| 2017 | 1.1.0 | . | 6 |
| 2017 | 1.2.0 | . | 7 |
| 2020 | 1.3.0 | . | 8 |
| 2020 | 1.3.1 | Current release | 9 |
See also
- Electronics portal
- 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 daughtercard standard with Pmod option
External links
- Pmod modules - Digilent
- Video, Pmod Peripheral Modules - YouTube
References
Pmod specification v1.3.1; Digilent; October 2020. https://digilent.com/reference/_media/reference/pmod/pmod-interface-specification-1_3_1.pdf ↩
Maxfield, Max (6 February 2020). "Big Things in Store for Digilent in 2020". embedded-computing.com. OpenSystems Media. Retrieved 21 September 2020. https://www.embedded-computing.com/guest-blogs/big-things-in-store-for-digilent-in-2020 ↩
Pmod specification v1.0.0; Digilent; November 2011. https://digilent.com/reference/lib/exe/fetch.php?tok=6c721a&media=https%3A%2F%2Fwww.digilentinc.com%2FPmods%2FDigilent-Pmod_%2520Interface_Specification.pdf ↩
"National Instruments acquires Digilent Inc". dangerousprototypes.com. Dangerous Prototypes self-published blog. 24 January 2013. Retrieved 21 September 2020. http://dangerousprototypes.com/blog/2013/01/24/national-instruments-acquires-digilent-inc/ ↩
Pmod specification v1.0.0; Digilent; November 2011. https://digilent.com/reference/lib/exe/fetch.php?tok=6c721a&media=https%3A%2F%2Fwww.digilentinc.com%2FPmods%2FDigilent-Pmod_%2520Interface_Specification.pdf ↩
Pmod specification v1.1.0; Digilent; July 2017. https://digilent.com/reference/_media/reference/pmod/pmod-interface-specification-1_1_0.pdf ↩
Pmod specification v1.2.0; Digilent; October 2017. https://digilent.com/reference/_media/reference/pmod/pmod-interface-specification-1_2_0.pdf ↩
Pmod specification v1.3.0; Digilent; September 2020. https://digilent.com/reference/_media/reference/pmod/pmod-interface-specification-1_3_0.pdf ↩
Pmod specification v1.3.1; Digilent; October 2020. https://digilent.com/reference/_media/reference/pmod/pmod-interface-specification-1_3_1.pdf ↩