//! Endlessly fill the screen with characters from the alphabet
//!
//! This example is for the STM32F103 "Blue Pill" board using I2C1.
//!
//! Wiring connections are as follows for a CRIUS-branded display:
//!
//! ```
//!      Display -> Blue Pill
//! (black)  GND -> GND
//! (red)    +5V -> VCC
//! (yellow) SDA -> PB7
//! (green)  SCL -> PB6
//! ```
//!
//! Run on a Blue Pill with `cargo run --example async_terminal_i2c`.

#![no_std]
#![no_main]

use defmt_rtt as _;
use embassy_executor::Spawner;
use embassy_stm32::{bind_interrupts, i2c, peripherals, time::Hertz};
use panic_probe as _;
use ssd1306::{prelude::*, I2CDisplayInterface, Ssd1306Async};

bind_interrupts!(struct Irqs {
    I2C1_EV => i2c::EventInterruptHandler<peripherals::I2C1>;
    I2C1_ER => i2c::ErrorInterruptHandler<peripherals::I2C1>;
});

#[embassy_executor::main]
async fn main(_spawner: Spawner) {
    let p = embassy_stm32::init(Default::default());
    let i2c = embassy_stm32::i2c::I2c::new(
        p.I2C1,
        p.PB6,
        p.PB7,
        Irqs,
        p.DMA1_CH6,
        p.DMA1_CH7,
        Hertz::khz(400),
        Default::default(),
    );

    let interface = I2CDisplayInterface::new(i2c);
    let mut display = Ssd1306Async::new(interface, DisplaySize128x64, DisplayRotation::Rotate0)
        .into_terminal_mode();
    display.init().await.unwrap();
    let _ = display.clear().await;

    /* Endless loop */
    loop {
        for c in 97..123 {
            let _ = display
                .write_str(unsafe { core::str::from_utf8_unchecked(&[c]) })
                .await;
        }
        for c in 65..91 {
            let _ = display
                .write_str(unsafe { core::str::from_utf8_unchecked(&[c]) })
                .await;
        }
    }
}