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//! This example shows how to use the PIO module in the RP2040 to read a quadrature rotary encoder.
#![no_std]
#![no_main]
use defmt::info;
use embassy_executor::Spawner;
use embassy_rp::gpio::Pull;
use embassy_rp::peripherals::PIO0;
use embassy_rp::{bind_interrupts, pio};
use fixed::traits::ToFixed;
use pio::{Common, Config, FifoJoin, Instance, InterruptHandler, Pio, PioPin, ShiftDirection, StateMachine};
use {defmt_rtt as _, panic_probe as _};
bind_interrupts!(struct Irqs {
PIO0_IRQ_0 => InterruptHandler<PIO0>;
});
pub struct PioEncoder<'d, T: Instance, const SM: usize> {
sm: StateMachine<'d, T, SM>,
}
impl<'d, T: Instance, const SM: usize> PioEncoder<'d, T, SM> {
pub fn new(
pio: &mut Common<'d, T>,
mut sm: StateMachine<'d, T, SM>,
pin_a: impl PioPin,
pin_b: impl PioPin,
) -> Self {
let mut pin_a = pio.make_pio_pin(pin_a);
let mut pin_b = pio.make_pio_pin(pin_b);
pin_a.set_pull(Pull::Up);
pin_b.set_pull(Pull::Up);
sm.set_pin_dirs(pio::Direction::In, &[&pin_a, &pin_b]);
let prg = pio_proc::pio_asm!("wait 1 pin 1", "wait 0 pin 1", "in pins, 2", "push",);
let mut cfg = Config::default();
cfg.set_in_pins(&[&pin_a, &pin_b]);
cfg.fifo_join = FifoJoin::RxOnly;
cfg.shift_in.direction = ShiftDirection::Left;
cfg.clock_divider = 10_000.to_fixed();
cfg.use_program(&pio.load_program(&prg.program), &[]);
sm.set_config(&cfg);
sm.set_enable(true);
Self { sm }
}
pub async fn read(&mut self) -> Direction {
loop {
match self.sm.rx().wait_pull().await {
0 => return Direction::CounterClockwise,
1 => return Direction::Clockwise,
_ => {}
}
}
}
}
pub enum Direction {
Clockwise,
CounterClockwise,
}
#[embassy_executor::main]
async fn main(_spawner: Spawner) {
let p = embassy_rp::init(Default::default());
let Pio { mut common, sm0, .. } = Pio::new(p.PIO0, Irqs);
let mut encoder = PioEncoder::new(&mut common, sm0, p.PIN_4, p.PIN_5);
let mut count = 0;
loop {
info!("Count: {}", count);
count += match encoder.read().await {
Direction::Clockwise => 1,
Direction::CounterClockwise => -1,
};
}
}
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