noise_i2c.rs

//! Send random raw data to the display, emulating an old untuned TV. This example retrieves the
//! underlying display properties struct and allows calling of the low-level `draw()` method,
//! sending a 1024 byte buffer straight to the display.
//!
//! 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 noise_i2c`. Best results when using `--release`.

#![no_std]
#![no_main]

use cortex_m_rt::entry;
use defmt_rtt as _;
#[cfg(feature = "async")]
use embassy_stm32::{bind_interrupts, i2c, peripherals};

use embassy_stm32::time::Hertz;
use panic_probe as _;
use rand::prelude::*;
use ssd1306::{prelude::*, I2CDisplayInterface, Ssd1306};

#[entry]
fn main() -> ! {
    let p = embassy_stm32::init(Default::default());
    #[cfg(feature = "async")]
    bind_interrupts!(struct Irqs {
        I2C1_EV => i2c::EventInterruptHandler<peripherals::I2C1>;
        I2C1_ER => i2c::ErrorInterruptHandler<peripherals::I2C1>;
    });

    #[cfg(feature = "async")]
    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(),
    );

    #[cfg(not(feature = "async"))]
    let i2c = embassy_stm32::i2c::I2c::new_blocking(
        p.I2C1,
        p.PB6,
        p.PB7,
        Hertz::khz(400),
        Default::default(),
    );

    let interface = I2CDisplayInterface::new(i2c);
    let mut display = Ssd1306::new(interface, DisplaySize128x64, DisplayRotation::Rotate0);
    display.init().unwrap();

    let mut buf = [0x00u8; 1024];

    let mut rng = SmallRng::seed_from_u64(0xdead_beef_cafe_d00d);

    loop {
        rng.fill_bytes(&mut buf);

        display.draw(&buf).unwrap();
    }
}