mirror of
https://github.com/italicsjenga/rp-hal-boards.git
synced 2024-10-17 22:41:30 +11:00
44019781e2
- Clippy warns about empty loops, https://github.com/rust-lang/rust-clippy/issues/6161 - wfi allows to CPU to save some power WFI was avoided in examples for fear of ill interactions with debuggers. However the rp2040 debug port does continue to work, as long as the relevant clocks are not disabled in SLEEP_EN0/SLEEP_EN1. (By default, all clocks stay enabled in sleep mode.) This patch replaces several different workarounds with just calling wfi.
71 lines
2 KiB
Rust
71 lines
2 KiB
Rust
//! This example toggles the GPIO25 pin, using a PIO program.
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//!
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//! If a LED is connected to that pin, like on a Pico board, the LED should blink.
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#![no_std]
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#![no_main]
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use cortex_m_rt::entry;
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use hal::gpio::{FunctionPio0, Pin};
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use hal::pac;
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use hal::pio::PIOExt;
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use hal::Sio;
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use panic_halt as _;
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use rp2040_hal as hal;
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#[link_section = ".boot2"]
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#[used]
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pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_W25Q080;
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#[entry]
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fn main() -> ! {
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let mut pac = pac::Peripherals::take().unwrap();
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let sio = Sio::new(pac.SIO);
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let pins = hal::gpio::Pins::new(
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pac.IO_BANK0,
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pac.PADS_BANK0,
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sio.gpio_bank0,
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&mut pac.RESETS,
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);
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// configure LED pin for Pio0.
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let _led: Pin<_, FunctionPio0> = pins.gpio25.into_mode();
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// PIN id for use inside of PIO
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let led_pin_id = 25;
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// Define some simple PIO program.
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const MAX_DELAY: u8 = 31;
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let mut a = pio::Assembler::<32>::new();
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let mut wrap_target = a.label();
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let mut wrap_source = a.label();
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// Set pin as Out
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a.set(pio::SetDestination::PINDIRS, 1);
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// Define begin of program loop
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a.bind(&mut wrap_target);
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// Set pin low
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a.set_with_delay(pio::SetDestination::PINS, 0, MAX_DELAY);
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// Set pin high
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a.set_with_delay(pio::SetDestination::PINS, 1, MAX_DELAY);
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// Define end of program loop
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a.bind(&mut wrap_source);
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// The labels wrap_target and wrap_source, as set above,
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// define a loop which is executed repeatedly by the PIO
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// state machine.
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let program = a.assemble_with_wrap(wrap_source, wrap_target);
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// Initialize and start PIO
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let (mut pio, sm0, _, _, _) = pac.PIO0.split(&mut pac.RESETS);
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let installed = pio.install(&program).unwrap();
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let div = 0f32; // as slow as possible (0 is interpreted as 65536)
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let (sm, _, _) = rp2040_hal::pio::PIOBuilder::from_program(installed)
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.set_pins(led_pin_id, 1)
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.clock_divisor(div)
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.build(sm0);
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sm.start();
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// PIO runs in background, independently from CPU
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loop {
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cortex_m::asm::wfi();
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}
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}
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