mirror of
https://github.com/italicsjenga/rp-hal-boards.git
synced 2024-12-24 05:01:31 +11:00
6026ea4ae3
* add example of synchronized PIOs * Synchronize state machines using WAIT IRQ instruction * Use "irq wait 0" instead of "wait 1 irq 0" This way, the initial value of the interrupt flag doesn't matter * Start state machines synchronized without IRQ WAIT instruction * Improve API Co-authored-by: Andrew Straw <strawman@astraw.com>
97 lines
2.9 KiB
Rust
97 lines
2.9 KiB
Rust
//! This example toggles the GPIO0 and GPIO1 pins, with each controlled from a
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//! separate PIO state machine.
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//!
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//! Despite running in separate state machines, the clocks are sychronized at
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//! the rise and fall times will be simultaneous.
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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 pins for Pio0.
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let _: Pin<_, FunctionPio0> = pins.gpio0.into_mode();
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let _: Pin<_, FunctionPio0> = pins.gpio1.into_mode();
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// PIN id for use inside of PIO
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let pin0 = 0;
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let pin1 = 1;
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// Define some simple PIO program.
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let program = pio_proc::pio_asm!(
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"
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.wrap_target
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set pins, 1 [31]
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set pins, 0 [31]
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.wrap
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"
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);
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// Initialize and start PIO
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let (mut pio, sm0, sm1, _, _) = pac.PIO0.split(&mut pac.RESETS);
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// I'm "measuring" the phase offset between the two pins by connecting
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// then through a LED. If there is a clock offset, there will be a
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// short time with a voltage between the pins, so the LED will flash up.
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// With a slow clock this is not visible, so use a reasonably fast clock.
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let div = 256f32;
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let installed = pio.install(&program.program).unwrap();
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let (mut sm0, _, _) = rp2040_hal::pio::PIOBuilder::from_program(installed)
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.set_pins(pin0, 1)
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.clock_divisor(div)
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.build(sm0);
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// The GPIO pin needs to be configured as an output.
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sm0.set_pindirs([(pin0, hal::pio::PinDir::Output)]);
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// NOTE: with the current rp-hal, I need to call pio.install() twice. This
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// should be investigated further as it seems wrong.
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let installed = pio.install(&program.program).unwrap();
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let (mut sm1, _, _) = rp2040_hal::pio::PIOBuilder::from_program(installed)
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.set_pins(pin1, 1)
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.clock_divisor(div)
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.build(sm1);
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// The GPIO pin needs to be configured as an output.
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sm1.set_pindirs([(pin1, hal::pio::PinDir::Output)]);
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// Start both SMs at the same time
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let group = sm0.with(sm1).sync().start();
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cortex_m::asm::delay(10_000_000);
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// Stop both SMs at the same time
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let group = group.stop();
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cortex_m::asm::delay(10_000_000);
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// Start them again and extract the individual state machines
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let (sm1, sm2) = group.start().free();
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cortex_m::asm::delay(10_000_000);
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// Stop the two state machines separately
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let _sm1 = sm1.stop();
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cortex_m::asm::delay(10_000_000);
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let _sm2 = sm2.stop();
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#[allow(clippy::empty_loop)]
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loop {}
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}
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