embassy/examples/rp/src/bin/adc.rs
pennae a6b8f3d994 rp: add single-channel dma from adc
with uniform treatment of adc inputs it's easy enough to add a new
sampling method. dma sampling only supports one channel at the moment,
though round-robin sampling would be a simple extension (probably a new
trait that's implemented for Channel and &[Channel]). continuous dma as
proposed in #1608 also isn't done here, we'd expect that to be a
compound dma::Channel that internally splits a buffer in half and
dispatches callbacks or something like that.
2023-08-02 17:04:32 +02:00

50 lines
1.7 KiB
Rust

//! 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_temp_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
}