//! # Rainbow Example for the Adafruit KB2040 //! //! Runs a rainbow-effect colour wheel on the on-board LED. //! //! Uses the `ws2812_pio` driver to control the LED, which in turns uses the //! RP2040's PIO block. #![no_std] #![no_main] use core::iter::once; use cortex_m_rt::entry; use embedded_hal::timer::CountDown; use embedded_time::duration::Extensions; use panic_halt as _; use adafruit_kb2040::{ hal::{ clocks::{init_clocks_and_plls, Clock}, pac, pio::PIOExt, timer::Timer, watchdog::Watchdog, Sio, }, XOSC_CRYSTAL_FREQ, }; use smart_leds::{brightness, SmartLedsWrite, RGB8}; use ws2812_pio::Ws2812; /// Entry point to our bare-metal application. /// /// The `#[entry]` macro ensures the Cortex-M start-up code calls this /// function as soon as all global variables are initialised. /// /// The function configures the RP2040 peripherals, then the LED, then runs /// the colour wheel in an infinite loop. #[entry] fn main() -> ! { // Configure the RP2040 peripherals let mut pac = pac::Peripherals::take().unwrap(); let mut watchdog = Watchdog::new(pac.WATCHDOG); let clocks = init_clocks_and_plls( XOSC_CRYSTAL_FREQ, pac.XOSC, pac.CLOCKS, pac.PLL_SYS, pac.PLL_USB, &mut pac.RESETS, &mut watchdog, ) .ok() .unwrap(); let sio = Sio::new(pac.SIO); let pins = adafruit_kb2040::Pins::new( pac.IO_BANK0, pac.PADS_BANK0, sio.gpio_bank0, &mut pac.RESETS, ); let timer = Timer::new(pac.TIMER, &mut pac.RESETS); let mut delay = timer.count_down(); // Configure the addressable LED let (mut pio, sm0, _, _, _) = pac.PIO0.split(&mut pac.RESETS); let mut ws = Ws2812::new( pins.neopixel.into_mode(), &mut pio, sm0, clocks.peripheral_clock.freq(), timer.count_down(), ); // Infinite colour wheel loop let mut n: u8 = 128; loop { ws.write(brightness(once(wheel(n)), 32)).unwrap(); n = n.wrapping_add(1); delay.start(25.milliseconds()); let _ = nb::block!(delay.wait()); } } /// Convert a number from `0..=255` to an RGB color triplet. /// /// The colours are a transition from red, to green, to blue and back to red. fn wheel(mut wheel_pos: u8) -> RGB8 { wheel_pos = 255 - wheel_pos; if wheel_pos < 85 { // No green in this sector - red and blue only (255 - (wheel_pos * 3), 0, wheel_pos * 3).into() } else if wheel_pos < 170 { // No red in this sector - green and blue only wheel_pos -= 85; (0, wheel_pos * 3, 255 - (wheel_pos * 3)).into() } else { // No blue in this sector - red and green only wheel_pos -= 170; (wheel_pos * 3, 255 - (wheel_pos * 3), 0).into() } }