embassy/examples/rp/src/bin/adc.rs

//! This example test the ADC (Analog to Digital Conversion) of the RS2040 pin 26, 27 and 28.
//! It also reads the temperature sensor in the chip.

#![no_std]
#![no_main]
#![feature(type_alias_impl_trait)]

use defmt::*;
use embassy_executor::Spawner;
use embassy_rp::adc::{Adc, Channel, Config, InterruptHandler};
use embassy_rp::bind_interrupts;
use embassy_rp::gpio::Pull;
use embassy_time::{Duration, Timer};
use {defmt_rtt as _, panic_probe as _};

bind_interrupts!(struct Irqs {
    ADC_IRQ_FIFO => InterruptHandler;
});

#[embassy_executor::main]
async fn main(_spawner: Spawner) {
    let p = embassy_rp::init(Default::default());
    let mut adc = Adc::new(p.ADC, Irqs, Config::default());

    let mut p26 = Channel::new_pin(p.PIN_26, Pull::None);
    let mut p27 = Channel::new_pin(p.PIN_27, Pull::None);
    let mut p28 = Channel::new_pin(p.PIN_28, Pull::None);
    let mut ts = Channel::new_sensor(p.ADC_TEMP_SENSOR);

    loop {
        let level = adc.read(&mut p26).await.unwrap();
        info!("Pin 26 ADC: {}", level);
        let level = adc.read(&mut p27).await.unwrap();
        info!("Pin 27 ADC: {}", level);
        let level = adc.read(&mut p28).await.unwrap();
        info!("Pin 28 ADC: {}", level);
        let temp = adc.read(&mut ts).await.unwrap();
        info!("Temp: {} degrees", convert_to_celsius(temp));
        Timer::after(Duration::from_secs(1)).await;
    }
}

fn convert_to_celsius(raw_temp: u16) -> f32 {
    // According to chapter 4.9.5. Temperature Sensor in RP2040 datasheet
    let temp = 27.0 - (raw_temp as f32 * 3.3 / 4096.0 - 0.706) / 0.001721;
    let sign = if temp < 0.0 { -1.0 } else { 1.0 };
    let rounded_temp_x10: i16 = ((temp * 10.0) + 0.5 * sign) as i16;
    (rounded_temp_x10 as f32) / 10.0
}