embassy/examples/stm32f4/src/bin/adc.rs
2022-10-24 15:27:12 -05:00

69 lines
2.1 KiB
Rust

#![no_std]
#![no_main]
#![feature(type_alias_impl_trait)]
use cortex_m::prelude::_embedded_hal_blocking_delay_DelayUs;
use defmt::*;
use embassy_executor::Spawner;
use embassy_stm32::adc::{Adc, Temperature, VrefInt};
use embassy_time::{Delay, Duration, Timer};
use {defmt_rtt as _, panic_probe as _};
#[embassy_executor::main]
async fn main(_spawner: Spawner) {
let p = embassy_stm32::init(Default::default());
info!("Hello World!");
let mut delay = Delay;
let mut adc = Adc::new(p.ADC1, &mut delay);
let mut pin = p.PC1;
let mut vrefint = adc.enable_vrefint();
let mut temp = adc.enable_temperature();
// Startup delay can be combined to the maximum of either
delay.delay_us(Temperature::start_time_us().max(VrefInt::start_time_us()));
let vrefint_sample = adc.read_internal(&mut vrefint);
let convert_to_millivolts = |sample| {
// From http://www.st.com/resource/en/datasheet/DM00071990.pdf
// 6.3.24 Reference voltage
const VREFINT_MV: u32 = 1210; // mV
(u32::from(sample) * VREFINT_MV / u32::from(vrefint_sample)) as u16
};
let convert_to_celcius = |sample| {
// From http://www.st.com/resource/en/datasheet/DM00071990.pdf
// 6.3.22 Temperature sensor characteristics
const V25: i32 = 760; // mV
const AVG_SLOPE: f32 = 2.5; // mV/C
let sample_mv = convert_to_millivolts(sample) as i32;
(sample_mv - V25) as f32 / AVG_SLOPE + 25.0
};
info!("VrefInt: {}", vrefint_sample);
const MAX_ADC_SAMPLE: u16 = (1 << 12) - 1;
info!("VCCA: {} mV", convert_to_millivolts(MAX_ADC_SAMPLE));
loop {
// Read pin
let v = adc.read(&mut pin);
info!("PC1: {} ({} mV)", v, convert_to_millivolts(v));
// Read internal temperature
let v = adc.read_internal(&mut temp);
let celcius = convert_to_celcius(v);
info!("Internal temp: {} ({} C)", v, celcius);
// Read internal voltage reference
let v = adc.read_internal(&mut vrefint);
info!("VrefInt: {}", v);
Timer::after(Duration::from_millis(100)).await;
}
}