rp-hal-boards/rp2040-hal/examples/pio_blink.rs
2021-09-25 13:22:13 +00:00

66 lines
1.8 KiB
Rust

//! Blinks the LED on a Pico board, using a PIO program
//!
//! This will blink an LED attached to GP25, which is the pin the Pico uses for the on-board LED.
#![no_std]
#![no_main]
use cortex_m_rt::entry;
use hal::gpio::{FunctionPio0, Pin};
use hal::pac;
use hal::sio::Sio;
use panic_halt as _;
use rp2040_hal as hal;
#[link_section = ".boot2"]
#[used]
pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER;
#[entry]
fn main() -> ! {
let mut pac = pac::Peripherals::take().unwrap();
let sio = Sio::new(pac.SIO);
let pins = hal::gpio::Pins::new(
pac.IO_BANK0,
pac.PADS_BANK0,
sio.gpio_bank0,
&mut pac.RESETS,
);
// configure LED pin for Pio0.
let _led: Pin<_, FunctionPio0> = pins.gpio25.into_mode();
// PIN id for use inside of PIO
let led_pin_id = 25;
// Define some simple PIO program.
const MAX_DELAY: u8 = 31;
let mut a = pio::Assembler::<32>::new();
let mut wrap_target = a.label();
let mut wrap_source = a.label();
// Set pin as Out
a.set(pio::SetDestination::PINDIRS, 1);
a.bind(&mut wrap_target);
// Set pin low
a.set_with_delay(pio::SetDestination::PINS, 0, MAX_DELAY);
// Set pin high
a.set_with_delay(pio::SetDestination::PINS, 1, MAX_DELAY);
// NOP
a.bind(&mut wrap_source);
let program = a.assemble_with_wrap(wrap_source, wrap_target);
// Initialize and start PIO
let pio = rp2040_hal::pio::PIO::new(pac.PIO0, &mut pac.RESETS);
let sm = &pio.state_machines()[0];
let div = 0f32; // as slow as possible (0 is interpreted as 65536)
rp2040_hal::pio::PIOBuilder::default()
.with_program(&program)
.set_pins(led_pin_id, 1)
.clock_divisor(div)
.build(&pio, sm)
.unwrap();
// PIO runs in background, independently from CPU
#[allow(clippy::empty_loop)]
loop {}
}