embassy/examples/rp/src/bin/pio_async.rs
pennae f4ade6af8b rp/pio: write instr memory only from common
instruction memory is a shared resource. writing it only from PioCommon
clarifies this, and perhaps makes it more obvious that multiple state
machines can share the same instructions.

this also allows *freeing* of instruction memory to reprogram the
system, although this interface is not entirely safe yet. it's safe in
the sense rusts understands things, but state machines may misbehave if
their instruction memory is freed and rewritten while they are running.
fixing this is out of scope for now since it requires some larger
changes to how state machines are handled. the interface provided
currently is already unsafe in that it lets people execute instruction
memory that has never been written, so this isn't much of a drawback for now.
2023-05-01 12:58:57 +02:00

126 lines
3.7 KiB
Rust

#![no_std]
#![no_main]
#![feature(type_alias_impl_trait)]
use defmt::info;
use embassy_executor::Spawner;
use embassy_rp::gpio::{AnyPin, Pin};
use embassy_rp::pio::{
Pio0, PioCommon, PioCommonInstance, PioPeripheral, PioStateMachine, PioStateMachineInstance, ShiftDirection, Sm0,
Sm1, Sm2,
};
use embassy_rp::pio_instr_util;
use embassy_rp::relocate::RelocatedProgram;
use {defmt_rtt as _, panic_probe as _};
fn setup_pio_task_sm0(pio: &mut PioCommonInstance<Pio0>, sm: &mut PioStateMachineInstance<Pio0, Sm0>, pin: AnyPin) {
// Setup sm0
// Send data serially to pin
let prg = pio_proc::pio_asm!(
".origin 16",
"set pindirs, 1",
".wrap_target",
"out pins,1 [19]",
".wrap",
);
let relocated = RelocatedProgram::new(&prg.program);
let out_pin = pio.make_pio_pin(pin);
let pio_pins = [&out_pin];
sm.set_out_pins(&pio_pins);
pio.write_instr(relocated.origin() as usize, relocated.code());
pio_instr_util::exec_jmp(sm, relocated.origin());
sm.set_clkdiv((125e6 / 20.0 / 2e2 * 256.0) as u32);
sm.set_set_range(0, 1);
let pio::Wrap { source, target } = relocated.wrap();
sm.set_wrap(source, target);
sm.set_autopull(true);
sm.set_out_shift_dir(ShiftDirection::Left);
}
#[embassy_executor::task]
async fn pio_task_sm0(mut sm: PioStateMachineInstance<Pio0, Sm0>) {
sm.set_enable(true);
let mut v = 0x0f0caffa;
loop {
sm.wait_push(v).await;
v ^= 0xffff;
info!("Pushed {:032b} to FIFO", v);
}
}
fn setup_pio_task_sm1(pio: &mut PioCommonInstance<Pio0>, sm: &mut PioStateMachineInstance<Pio0, Sm1>) {
// Setupm sm1
// Read 0b10101 repeatedly until ISR is full
let prg = pio_proc::pio_asm!(".origin 8", "set x, 0x15", ".wrap_target", "in x, 5 [31]", ".wrap",);
let relocated = RelocatedProgram::new(&prg.program);
pio.write_instr(relocated.origin() as usize, relocated.code());
pio_instr_util::exec_jmp(sm, relocated.origin());
sm.set_clkdiv((125e6 / 2e3 * 256.0) as u32);
sm.set_set_range(0, 0);
let pio::Wrap { source, target } = relocated.wrap();
sm.set_wrap(source, target);
sm.set_autopush(true);
sm.set_in_shift_dir(ShiftDirection::Right);
}
#[embassy_executor::task]
async fn pio_task_sm1(mut sm: PioStateMachineInstance<Pio0, Sm1>) {
sm.set_enable(true);
loop {
let rx = sm.wait_pull().await;
info!("Pulled {:032b} from FIFO", rx);
}
}
fn setup_pio_task_sm2(pio: &mut PioCommonInstance<Pio0>, sm: &mut PioStateMachineInstance<Pio0, Sm2>) {
// Setup sm2
// Repeatedly trigger IRQ 3
let prg = pio_proc::pio_asm!(
".origin 0",
".wrap_target",
"set x,10",
"delay:",
"jmp x-- delay [15]",
"irq 3 [15]",
".wrap",
);
let relocated = RelocatedProgram::new(&prg.program);
pio.write_instr(relocated.origin() as usize, relocated.code());
let pio::Wrap { source, target } = relocated.wrap();
sm.set_wrap(source, target);
pio_instr_util::exec_jmp(sm, relocated.origin());
sm.set_clkdiv((125e6 / 2e3 * 256.0) as u32);
}
#[embassy_executor::task]
async fn pio_task_sm2(mut sm: PioStateMachineInstance<Pio0, Sm2>) {
sm.set_enable(true);
loop {
sm.wait_irq(3).await;
info!("IRQ trigged");
}
}
#[embassy_executor::main]
async fn main(spawner: Spawner) {
let p = embassy_rp::init(Default::default());
let pio = p.PIO0;
let (mut pio0, mut sm0, mut sm1, mut sm2, ..) = pio.split();
setup_pio_task_sm0(&mut pio0, &mut sm0, p.PIN_0.degrade());
setup_pio_task_sm1(&mut pio0, &mut sm1);
setup_pio_task_sm2(&mut pio0, &mut sm2);
spawner.spawn(pio_task_sm0(sm0)).unwrap();
spawner.spawn(pio_task_sm1(sm1)).unwrap();
spawner.spawn(pio_task_sm2(sm2)).unwrap();
}