/*
For a detailed explanation of this code check out the associated blog post:
https://apollolabsblog.hashnode.dev/esp32-embedded-rust-at-the-hal-gpio-interrupts
GitHub Repo containing source code and other examples:
https://github.com/apollolabsdev
For notifications on similar examples and more, subscribe to newsletter here:
https://www.theembeddedrustacean.com/subscribe
*/
#![no_std]
#![no_main]
use core::cell::{Cell, RefCell};
use critical_section::Mutex;
use esp32c3_hal::{
clock::ClockControl,
esp_riscv_rt::entry,
gpio::{Event, Gpio0, Input, PullUp},
interrupt,
prelude::*,
soc::peripherals::{Interrupt, Peripherals},
timer::TimerGroup,
Delay,
Rtc,
IO,
};
use esp_backtrace as _;
use esp_println::println;
// Global Variable Definitions
// Global variables are wrapped in safe abstractions.
// Peripherals are wrapped in a different manner than regular global mutable data.
// In the case of peripherals we must be sure only one refrence exists at a time.
// Refer to Chapter 6 of the Embedded Rust Book for more detail.
// Create a Global Variable for the GPIO Peripheral to pass around between threads.
static G_BUTTON: Mutex<RefCell<Option<Gpio0<Input<PullUp>>>>> = Mutex::new(RefCell::new(None));
// Create a Global Variable for the delay value to pass around between threads.
static G_DELAYMS: Mutex<Cell<u32>> = Mutex::new(Cell::new(2000_u32));
#[entry]
fn main() -> ! {
// Take Peripherals, Initialize Clocks, and Create a Handle for Each
let peripherals = Peripherals::take();
let mut system = peripherals.SYSTEM.split();
let clocks = ClockControl::boot_defaults(system.clock_control).freeze();
// Instantiate and Create Handles for the RTC and TIMG watchdog timers
let mut rtc = Rtc::new(peripherals.RTC_CNTL);
let timer_group0 = TimerGroup::new(
peripherals.TIMG0,
&clocks,
&mut system.peripheral_clock_control,
);
let mut wdt0 = timer_group0.wdt;
let timer_group1 = TimerGroup::new(
peripherals.TIMG1,
&clocks,
&mut system.peripheral_clock_control,
);
let mut wdt1 = timer_group1.wdt;
// Disable the RTC and TIMG watchdog timers
rtc.swd.disable();
rtc.rwdt.disable();
wdt0.disable();
wdt1.disable();
// Instantiate and Create Handle for IO
let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);
// Instantiate and Create Handle for LED output & Button Input
let mut led = io.pins.gpio4.into_push_pull_output();
let mut button = io.pins.gpio0.into_pull_up_input();
// 1) Configure button for interrupt on falling edge and make it interrupt source
button.listen(Event::FallingEdge);
// 2) Enable gpio interrupts and set priority
interrupt::enable(Interrupt::GPIO, interrupt::Priority::Priority3).unwrap();
// 3) Enable Interrupts Globally in the risc-v Core
unsafe {
esp32c3_hal::esp_riscv_rt::riscv::interrupt::enable();
}
// Now that button is configured, move button into global context
critical_section::with(|cs| G_BUTTON.borrow_ref_mut(cs).replace(button));
// Create Delay Handle
let mut delay = Delay::new(&clocks);
// Application Loop
loop {
// Turn On LED
led.set_high().unwrap();
// Acquire updated G_DELAYMS and delay
delay.delay_ms(critical_section::with(|cs| G_DELAYMS.borrow(cs).get()));
// Turn off LED
led.set_low().unwrap();
// Acquire updated G_DELAYMS and delay
delay.delay_ms(critical_section::with(|cs| G_DELAYMS.borrow(cs).get()));
}
#[interrupt]
fn GPIO() {
// Print for sanity to confirm interrupt is detecte
println!("Button Press Interrupt!");
// Start a Critical Section
critical_section::with(|cs| {
// Obtain Access to Delay Global Data and Adjust Delay
G_DELAYMS
.borrow(cs)
.set(G_DELAYMS.borrow(cs).get() - 500_u32);
if G_DELAYMS.borrow(cs).get() < 500_u32 {
G_DELAYMS.borrow(cs).set(2000_u32);
}
// Obtain access to Global Button Peripheral and Clear Interrupt Pending Flag
G_BUTTON
.borrow_ref_mut(cs)
.as_mut()
.unwrap()
.clear_interrupt();
});
}
}