Crate pio_uart

PioUart Crate

This crate provides a UART implementation using the PIO hardware on the RP2040 microcontroller. It’s designed to work with the rp2040_hal crate and provides a UART interface through the Programmable I/O (PIO) subsystem.

Features

• UART communication using PIO
• Flexible pin assignment for RX and TX
• Customizable baud rate and system frequency settings
• Non-blocking read and write operations

Usage

To use this crate, ensure that you have rp2040_hal and embedded-hal as dependencies in your Cargo.toml. You’ll need to configure the PIO and state machines to set up the UART interface.

Example

use pio_uart::PioUart;
use embedded_io::{Read, Write};
use fugit::ExtU32;

fn main() {
    // Normal system initialization
    let mut pac = pac::Peripherals::take().unwrap();
    let core = pac::CorePeripherals::take().unwrap();
    let mut watchdog = hal::Watchdog::new(pac.WATCHDOG);
    let clocks = hal::clocks::init_clocks_and_plls(
        rp_pico::XOSC_CRYSTAL_FREQ, pac.XOSC, pac.CLOCKS,
        pac.PLL_SYS, pac.PLL_USB, &mut pac.RESETS, &mut watchdog,
    ).ok().unwrap();
    let sio = hal::Sio::new(pac.SIO);
    let pins = rp_pico::Pins::new(pac.IO_BANK0, pac.PADS_BANK0, sio.gpio_bank0, &mut pac.RESETS);

    // Initialize software UART
    let mut uart = pio_uart::PioUart::new(
            pac.PIO0,
            pins.gpio16.reconfigure(),
            pins.gpio17.reconfigure(),
            &mut pac.RESETS,
            19200.Hz(),
            125.MHz(),
        );

    uart.write(b"Hello, UART over PIO!");
    let mut buffer = [0u8; 10];
    uart.read(&mut buffer);
}

Structs

PioUart

Represents a UART interface using the RP2040’s PIO hardware.

PioUartRx

Represents the Rx part of a UART interface using the RP2040’s PIO hardware.

PioUartTx

Represents the Tx part of a UART interface using the RP2040’s PIO hardware.

RxProgram

Token of the already installed UART Rx program. To be obtained with install_rx_program.

TxProgram

Token of the already installed UART Tx program. To be obtained with install_tx_program.

Enums

PioSerialError

Represents errors that can occur in the PIO UART.

Functions

install_rx_program

Install the UART Rx program in a PIO instance

install_tx_program

Install the UART Tx program in a PIO instance