main.rs

#![no_std]
#![no_main]

use defmt::info;
use embassy_executor::Spawner;
use embassy_stm32::gpio::{AfType, Flex, OutputType, Speed};
use embassy_stm32::ltdc::{B7Pin, ClkPin, DePin, G7Pin, HsyncPin, Ltdc, LtdcConfiguration, LtdcLayer, LtdcLayerConfig, PixelFormat, PolarityActive, PolarityEdge, R7Pin, VsyncPin};
use embassy_stm32::peripherals::LTDC;
use embassy_stm32::rcc;
use embassy_stm32::rcc::Pll;
use embassy_time::Timer;
use {defmt_rtt as _, embassy_stm32 as _, panic_probe as _};

static FBUF: [u16; 320 * 240] = [0xffe0u16; 320 * 240];

#[embassy_executor::main]
async fn main(_spawner: Spawner) {
    let mut config = embassy_stm32::Config::default();
    config.rcc.supply_config = rcc::SupplyConfig::LDO;
    config.rcc.voltage_scale = rcc::VoltageScale::Scale0;
    config.rcc.hsi = Some(rcc::HSIPrescaler::DIV1);

    // configure for a 5.12 mhz ltdc clk
    config.rcc.pll3 = Some(
        Pll {
            source: rcc::PllSource::HSI,
            prediv: rcc::PllPreDiv::DIV4,
            mul: rcc::PllMul::MUL16,
            divp: None,
            divq: None,
            divr: Some(rcc::PllDiv::DIV50),
        }
    );

    let p = embassy_stm32::init(config);

    let mut ltdc = Ltdc::new(p.LTDC);
    ltdc.init(&LtdcConfiguration {
        active_width: 320,
        active_height: 240,
        h_back_porch: 20,
        h_front_porch: 10,
        v_back_porch: 2,
        v_front_porch: 4,
        h_sync: 10,
        v_sync: 2,
        h_sync_polarity: PolarityActive::ActiveLow,
        v_sync_polarity: PolarityActive::ActiveLow,
        data_enable_polarity: PolarityActive::ActiveLow,
        pixel_clock_polarity: PolarityEdge::FallingEdge,
    });

    // Enable a couple pins so we can demonstrate it's still generating a signal
    let num = <embassy_stm32::peripherals::PC6 as HsyncPin<LTDC>>::af_num(&p.PC6);
    let mut hsync = Flex::new(p.PC6);
    hsync.set_as_af_unchecked(num, AfType::output(OutputType::PushPull, Speed::VeryHigh));

    let num = <embassy_stm32::peripherals::PC4 as R7Pin<LTDC>>::af_num(&p.PC4);
    let mut r7 = Flex::new(p.PC4);
    r7.set_as_af_unchecked(num, AfType::output(OutputType::PushPull, Speed::VeryHigh));

    let num = <embassy_stm32::peripherals::PD2 as B7Pin<LTDC>>::af_num(&p.PD2);
    let mut b7 = Flex::new(p.PD2);
    b7.set_as_af_unchecked(num, AfType::output(OutputType::PushPull, Speed::VeryHigh));

    ltdc.init_layer(&LtdcLayerConfig {
        layer: LtdcLayer::Layer1,
        pixel_format: PixelFormat::RGB565,
        window_x0: 0,
        window_x1: 319,
        window_y0: 0,
        window_y1: 239,
    }, None);

    ltdc.enable();

    // This line causes nothing after it to execute... but it DOES set the buffer!
    ltdc.set_buffer(LtdcLayer::Layer1, FBUF.as_ptr() as *const _).await.unwrap();

    loop {
        info!("tick");
        Timer::after_secs(1).await;
    }
}