rp-hal-boards/rp2040-hal/examples/multicore_polyblink.rs

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2022-05-08 18:29:27 +10:00
//! # Multicore Blinking Example
//!
//! This application blinks two LEDs on GPIOs 2 and 3 at different rates (3Hz
//! and 4Hz respectively.)
//!
//! See the `Cargo.toml` file for Copyright and licence details.
#![no_std]
#![no_main]
use cortex_m::delay::Delay;
use hal::clocks::Clock;
use hal::gpio::Pins;
use hal::multicore::{Multicore, Stack};
use hal::sio::Sio;
// Ensure we halt the program on panic (if we don't mention this crate it won't
// be linked)
use panic_halt as _;
// Alias for our HAL crate
use rp2040_hal as hal;
// A shorter alias for the Peripheral Access Crate, which provides low-level
// register access
use hal::pac;
// Some traits we need
use embedded_hal::digital::v2::ToggleableOutputPin;
/// The linker will place this boot block at the start of our program image. We
/// need this to help the ROM bootloader get our code up and running.
#[link_section = ".boot2"]
#[used]
pub static BOOT2: [u8; 256] = rp2040_boot2::BOOT_LOADER_GENERIC_03H;
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/// External high-speed crystal on the Raspberry Pi Pico board is 12 MHz. Adjust
/// if your board has a different frequency
const XTAL_FREQ_HZ: u32 = 12_000_000u32;
/// The frequency at which core 0 will blink its LED (Hz).
const CORE0_FREQ: u32 = 3;
/// The frequency at which core 1 will blink its LED (Hz).
const CORE1_FREQ: u32 = 4;
/// The delay between each toggle of core 0's LED (us).
const CORE0_DELAY: u32 = 1_000_000 / CORE0_FREQ;
/// The delay between each toggle of core 1's LED (us).
const CORE1_DELAY: u32 = 1_000_000 / CORE1_FREQ;
/// Stack for core 1
///
/// Core 0 gets its stack via the normal route - any memory not used by static
/// values is reserved for stack and initialised by cortex-m-rt.
/// To get the same for Core 1, we would need to compile everything seperately
/// and modify the linker file for both programs, and that's quite annoying.
/// So instead, core1.spawn takes a [usize] which gets used for the stack.
/// NOTE: We use the `Stack` struct here to ensure that it has 32-byte
/// alignment, which allows the stack guard to take up the least amount of
/// usable RAM.
static mut CORE1_STACK: Stack<4096> = Stack::new();
/// Entry point to our bare-metal application.
///
/// The `#[rp2040_hal::entry]` macro ensures the Cortex-M start-up code calls this function
/// as soon as all global variables and the spinlock are initialised.
#[rp2040_hal::entry]
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fn main() -> ! {
// Grab our singleton objects
let mut pac = pac::Peripherals::take().unwrap();
let core = pac::CorePeripherals::take().unwrap();
// Set up the watchdog driver - needed by the clock setup code
let mut watchdog = hal::watchdog::Watchdog::new(pac.WATCHDOG);
// Configure the clocks
let clocks = hal::clocks::init_clocks_and_plls(
XTAL_FREQ_HZ,
pac.XOSC,
pac.CLOCKS,
pac.PLL_SYS,
pac.PLL_USB,
&mut pac.RESETS,
&mut watchdog,
)
.ok()
.unwrap();
// Set up the GPIO pins
let mut sio = Sio::new(pac.SIO);
let pins = Pins::new(
pac.IO_BANK0,
pac.PADS_BANK0,
sio.gpio_bank0,
&mut pac.RESETS,
);
let mut led1 = pins.gpio2.into_push_pull_output();
let mut led2 = pins.gpio3.into_push_pull_output();
// Set up the delay for the first core.
let sys_freq = clocks.system_clock.freq().to_Hz();
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let mut delay = Delay::new(core.SYST, sys_freq);
// Start up the second core to blink the second LED
let mut mc = Multicore::new(&mut pac.PSM, &mut pac.PPB, &mut sio.fifo);
let cores = mc.cores();
let core1 = &mut cores[1];
core1
.spawn(unsafe { &mut CORE1_STACK.mem }, move || {
// Get the second core's copy of the `CorePeripherals`, which are per-core.
// Unfortunately, `cortex-m` doesn't support this properly right now,
// so we have to use `steal`.
let core = unsafe { pac::CorePeripherals::steal() };
// Set up the delay for the second core.
let mut delay = Delay::new(core.SYST, sys_freq);
// Blink the second LED.
loop {
led2.toggle().unwrap();
delay.delay_us(CORE1_DELAY)
}
})
.unwrap();
// Blink the first LED.
loop {
led1.toggle().unwrap();
delay.delay_us(CORE0_DELAY)
}
}
// End of file