Pmod Drivers
Package Structure
The lbutils.pmods package provides drivers and support for the Digilent Peripheral Modules. This library is designed to provide drivers and support for the Digilent peripheral modules. Not all boards are supported: and in some cases only certain busses are supported (e.g. using only the I2C bus, even though the pmod supports both I2C and SPI).
These packages are organised into the following structure, with gpio, i2c and spi documented separately in more detail.
SPI Conventions
Modern SPI Name in Use
For this module, and all SPI references in the library, the [modern SPI names] (https://www.oshwa.org/a-resolution-to-redefine-spi-signal-names/), shown in Figure 1, are in use. However, most of the PMod reference documentation (and the underlying hardware devices) still use the older terms. Some translation will therefore be necessary when cross-referencing between this documentation and older SPI references. A summary of the new pin names is given below.
Figure 1: Modern Naming Conventions for the SPI Interfaces [CC0 – Public Domain]
In general each module will require a minimum of four pins for the SPI interface, as shown in Figure 1. For the SPI modes in the PMod Interface Specification Version 1.2.0 at least two pins are additionally required for +3.3V (Pins 6 and 12) and 0V (Pin 5 and 11). This means that for most PMods using the 12-pin SPI jumper interface, the following basic pattern will hold (numbers refer to the default GPIO pin assignment for the Pico H/W on the Leeds Beckett micro-controller development board)
| Pin Name | Number | Description | |
|---|---|---|---|
| Pin 1 | CS | 14 | SPI Chip Select |
| Pin 2 | SDO | 19 | SPI Serial Data Out |
| Pin 3 | SDI | 16 | SPI Serial Data In |
| Pin 4 | SCK | 17 | SPI Serial Clock |
| Pin 5 | GND | 3 | Ground |
| Pin 6 | VCC | 5 | VCC (+3.3V) |
| Pin 7 | |||
| Pin 8 | |||
| Pin 9 | |||
| Pin 10 | |||
| Pin 11 | GND | 3 | Ground |
| Pin 12 | VCC | 5 | VCC (+3.3V) |
Examples for specific pin interfaces for individual modules can be found in the 'examples' folder: or in the documentation for each class below.
Tested Implementations
This version is written for MicroPython 3.4, and has been tested on:
- Raspberry Pi Pico H/W