Provides clean API to interact with RP2040's on-board Programable Input/Output (PIO) block. See chapter 3 of the RP2040 datasheet for more information.
This module contains the piolib package which contains importable drivers for use with a PIO such as:
- SPI driver
- 8-pin send-only parallel bus
- WS2812 (Neopixel) driver
- A pulse-constrained square wave generator (Pulsar)
The PIO is a versatile hardware interface. It can support a variety of IO standards, including:
- 8080 and 6800 parallel bus
- I2C
- 3-pin I2S
- SDIO
- SPI, DSPI, QSPI
- UART
- DPI or VGA (via resistor DAC)
PIO is programmable in the same sense as a processor and has a total of nine instructions: JMP, WAIT, IN, OUT, PUSH, PULL, MOV, IRQ, and SET. These are programmed in PIO assembly format describing a PIO program, where each command corresponds to one instruction in the output binary. Below is an example program in PIO assembly:
.program squarewave
again:
set pins, 1 [1] ; Drive pin high and then delay for one cycle
set pins, 0 ; Drive pin low
jmp again ; Set PC to label `again`
