ESP32 bare-metal Rust display code

main.rs

#![no_std]
#![no_main]

extern crate alloc;
use core::mem::MaybeUninit;
use embedded_graphics::geometry::Dimensions;
use embedded_graphics::mono_font::ascii::FONT_6X10;
use embedded_graphics::mono_font::MonoTextStyleBuilder;
use embedded_graphics::pixelcolor::BinaryColor;
use embedded_graphics::prelude::*;
use embedded_graphics::text::{Alignment, Text};
use esp_backtrace as _;
use esp_println::println;
use hal::i2c::I2C;
use hal::timer::TimerGroup;
use hal::{clock::ClockControl, peripherals::Peripherals, prelude::*, Delay, IO};
use log::info;
use ssd1306::prelude::DisplayRotation;
use ssd1306::prelude::*;
use ssd1306::{I2CDisplayInterface, Ssd1306};

#[global_allocator]
static ALLOCATOR: esp_alloc::EspHeap = esp_alloc::EspHeap::empty();

fn init_heap() {
    const HEAP_SIZE: usize = 32 * 1024;
    static mut HEAP: MaybeUninit<[u8; HEAP_SIZE]> = MaybeUninit::uninit();

    unsafe {
        ALLOCATOR.init(HEAP.as_mut_ptr() as *mut u8, HEAP_SIZE);
    }
}

#[entry]
fn main() -> ! {
    init_heap();
    let peripherals = Peripherals::take();
    let mut system = peripherals.DPORT.split();
    let clocks = ClockControl::boot_defaults(system.clock_control).freeze();
    let mut delay = Delay::new(&clocks);

    // setup logger
    // To change the log_level change the env section in .config/cargo.toml
    // or remove it and set ESP_LOGLEVEL manually before running cargo run
    // this requires a clean rebuild because of https://github.com/rust-lang/cargo/issues/10358
    esp_println::logger::init_logger_from_env();
    info!("Logger is setup");
    println!("Hello world!");
    let timer_group0 = TimerGroup::new(
        peripherals.TIMG0,
        &clocks,
        &mut system.peripheral_clock_control,
    );
    let mut timer = timer_group0.timer0;
    let io = IO::new(peripherals.GPIO, peripherals.IO_MUX);
    let i2c = I2C::new(
        peripherals.I2C0,
        io.pins.gpio17,
        io.pins.gpio18,
        100_u32.kHz(),
        &mut system.peripheral_clock_control,
        &clocks,
    );
    timer.start(5u64.secs());

    let i2c_interface = I2CDisplayInterface::new(i2c);
    let mut display = Ssd1306::new(
        i2c_interface,
        ssd1306::size::DisplaySize128x64,
        DisplayRotation::Rotate0,
    )
    .into_buffered_graphics_mode();
    display.init().unwrap();

    // Specify different text styles
    let text_style = MonoTextStyleBuilder::new()
        .font(&FONT_6X10)
        .text_color(BinaryColor::On)
        .build();
    Text::with_alignment(
        "esp-hal",
        display.bounding_box().center() + Point::new(0, 0),
        text_style,
        Alignment::Center,
    )
    .draw(&mut display)
    .unwrap();

    loop {
        println!("Loop...");
        delay.delay_ms(500u32);
    }
}