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Switch to DMA, use new clocks, don't take ownership of pio common

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This commit is contained in:
Caleb Jamison 2023-05-19 16:48:47 -04:00
parent 1be6e53316
commit 1ebb742fbf
1 changed files with 31 additions and 13 deletions
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44
examples/rp/src/bin/pio_ws2812.rs
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@ -4,18 +4,30 @@
use defmt::*;
use embassy_executor::Spawner;
use embassy_rp::dma::{AnyChannel, Channel};
use embassy_rp::pio::{Common, Config, FifoJoin, Instance, Pio, PioPin, ShiftConfig, ShiftDirection, StateMachine};
use embassy_rp::relocate::RelocatedProgram;
use embassy_rp::{clocks, into_ref, Peripheral, PeripheralRef};
use embassy_time::{Duration, Timer};
use fixed::types::U24F8;
use fixed_macro::fixed;
use smart_leds::RGB8;
use {defmt_rtt as _, panic_probe as _};
pub struct Ws2812<'d, P: Instance, const S: usize> {
pub struct Ws2812<'d, P: Instance, const S: usize, const N: usize> {
dma: PeripheralRef<'d, AnyChannel>,
sm: StateMachine<'d, P, S>,
}
impl<'d, P: Instance, const S: usize> Ws2812<'d, P, S> {
pub fn new(mut pio: Common<'d, P>, mut sm: StateMachine<'d, P, S>, pin: impl PioPin) -> Self {
impl<'d, P: Instance, const S: usize, const N: usize> Ws2812<'d, P, S, N> {
pub fn new(
pio: &mut Common<'d, P>,
mut sm: StateMachine<'d, P, S>,
dma: impl Peripheral<P = impl Channel> + 'd,
pin: impl PioPin,
) -> Self {
into_ref!(dma);
// Setup sm0
// prepare the PIO program
@ -56,7 +68,7 @@ impl<'d, P: Instance, const S: usize> Ws2812<'d, P, S> {
// Clock config, measured in kHz to avoid overflows
// TODO CLOCK_FREQ should come from embassy_rp
let clock_freq = fixed!(125_000: U24F8);
let clock_freq = U24F8::from_num(clocks::clk_sys_freq() / 1000);
let ws2812_freq = fixed!(800: U24F8);
let bit_freq = ws2812_freq * CYCLES_PER_BIT;
cfg.clock_divider = clock_freq / bit_freq;
@ -72,16 +84,22 @@ impl<'d, P: Instance, const S: usize> Ws2812<'d, P, S> {
sm.set_config(&cfg);
sm.set_enable(true);
Self { sm }
Self {
dma: dma.map_into(),
sm,
}
}
pub async fn write(&mut self, colors: &[RGB8]) {
for color in colors {
let word = (u32::from(color.g) << 24) | (u32::from(color.r) << 16) | (u32::from(color.b) << 8);
if !self.sm.tx().try_push(word) {
self.sm.tx().wait_push(word).await;
}
pub async fn write(&mut self, colors: &[RGB8; N]) {
// Precompute the word bytes from the colors
let mut words = [0u32; N];
for i in 0..N {
let word = (u32::from(colors[i].g) << 24) | (u32::from(colors[i].r) << 16) | (u32::from(colors[i].b) << 8);
words[i] = word;
}
// DMA transfer
self.sm.tx().dma_push(self.dma.reborrow(), &words).await;
}
}
@ -105,7 +123,7 @@ async fn main(_spawner: Spawner) {
info!("Start");
let p = embassy_rp::init(Default::default());
let Pio { common, sm0, .. } = Pio::new(p.PIO0);
let Pio { mut common, sm0, .. } = Pio::new(p.PIO0);
// This is the number of leds in the string. Helpfully, the sparkfun thing plus and adafruit
// feather boards for the 2040 both have one built in.
@ -114,7 +132,7 @@ async fn main(_spawner: Spawner) {
// For the thing plus, use pin 8
// For the feather, use pin 16
let mut ws2812 = Ws2812::new(common, sm0, p.PIN_8);
let mut ws2812 = Ws2812::new(&mut common, sm0, p.DMA_CH0, p.PIN_16);
// Loop forever making RGB values and pushing them out to the WS2812.
loop {