esp-hal/esp32s2-hal/examples/hello_rgb.rs

//! RGB LED Demo
//!
//! This example drives an SK68XX RGB LED that is connected to GPIO18.
//! A RGB LED is connected to that pin on the official DevKits.
//!
//! The demo will leverage the [`smart_leds`](https://crates.io/crates/smart-leds)
//! crate functionality to circle through the HSV hue color space (with
//! saturation and value both at 255). Additionally, we apply a gamma correction
//! and limit the brightness to 10 (out of 255).

#![no_std]
#![no_main]

use esp32s2_hal::{clock::ClockControl, peripherals::Peripherals, prelude::*, rmt::Rmt, Delay, IO};
use esp_backtrace as _;
use esp_hal_smartled::{smartLedBuffer, SmartLedsAdapter};
use smart_leds::{
    brightness,
    gamma,
    hsv::{hsv2rgb, Hsv},
    SmartLedsWrite,
};

#[entry]
fn main() -> ! {
    let peripherals = Peripherals::take();
    let system = peripherals.SYSTEM.split();
    let clocks = ClockControl::boot_defaults(system.clock_control).freeze();

    let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);

    // Configure RMT peripheral globally
    let rmt = Rmt::new(peripherals.RMT, 80u32.MHz(), &clocks).unwrap();

    // We use one of the RMT channels to instantiate a `SmartLedsAdapter` which can
    // be used directly with all `smart_led` implementations
    let rmt_buffer = smartLedBuffer!(1);
    let mut led = SmartLedsAdapter::new(rmt.channel0, io.pins.gpio18, rmt_buffer, &clocks);

    // Initialize the Delay peripheral, and use it to toggle the LED state in a
    // loop.
    let mut delay = Delay::new(&clocks);

    let mut color = Hsv {
        hue: 0,
        sat: 255,
        val: 255,
    };
    let mut data;

    loop {
        // Iterate over the rainbow!
        for hue in 0..=255 {
            color.hue = hue;
            // Convert from the HSV color space (where we can easily transition from one
            // color to the other) to the RGB color space that we can then send to the LED
            data = [hsv2rgb(color)];
            // When sending to the LED, we do a gamma correction first (see smart_leds
            // documentation for details) and then limit the brightness to 10 out of 255 so
            // that the output it's not too bright.
            led.write(brightness(gamma(data.iter().cloned()), 10))
                .unwrap();
            delay.delay_ms(20u8);
        }
    }
}