Add DAC HIL test with ADC

tests/stm32/src/bin/dac.rs

@@ -0,0 +1,81 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+// required-features: dac-adc-pin
+
+#[path = "../common.rs"]
+mod common;
+use common::*;
+use defmt::assert;
+use embassy_executor::Spawner;
+use embassy_stm32::adc::Adc;
+use embassy_stm32::dac::{DacCh1, DacChannel, Value};
+use embassy_stm32::dma::NoDma;
+use embassy_time::{Delay, Duration, Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    // Initialize the board and obtain a Peripherals instance
+    let p: embassy_stm32::Peripherals = embassy_stm32::init(config());
+
+    #[cfg(feature = "stm32f429zi")]
+    let dac_peripheral = p.DAC;
+
+    #[cfg(any(feature = "stm32h755zi", feature = "stm32g071rb"))]
+    let dac_peripheral = p.DAC1;
+
+    let mut dac: DacCh1<'_, _, NoDma> = DacCh1::new(dac_peripheral, NoDma, p.PA4);
+    unwrap!(dac.set_trigger_enable(false));
+
+    let mut adc = Adc::new(p.ADC1, &mut Delay);
+
+    #[cfg(feature = "stm32h755zi")]
+    let normalization_factor = 256;
+    #[cfg(any(feature = "stm32f429zi", feature = "stm32g071rb"))]
+    let normalization_factor: i32 = 16;
+
+    unwrap!(dac.set(Value::Bit8(0)));
+    // Now wait a little to obtain a stable value
+    Timer::after(Duration::from_millis(30)).await;
+    let offset = adc.read(&mut unsafe { embassy_stm32::Peripherals::steal() }.PA4);
+
+    for v in 0..=255 {
+        // First set the DAC output value
+        let dac_output_val = to_sine_wave(v);
+        unwrap!(dac.set(Value::Bit8(dac_output_val)));
+
+        // Now wait a little to obtain a stable value
+        Timer::after(Duration::from_millis(30)).await;
+
+        // Need to steal the peripherals here because PA4 is obviously in use already
+        let measured = adc.read(&mut unsafe { embassy_stm32::Peripherals::steal() }.PA4);
+        // Calibrate and normalize the measurement to get close to the dac_output_val
+        let measured_normalized = ((measured as i32 - offset as i32) / normalization_factor) as i16;
+
+        info!("value / measured: {} / {}", dac_output_val, measured_normalized);
+
+        // The deviations are quite enormous but that does not matter since this is only a quick test
+        assert!((dac_output_val as i16 - measured_normalized).abs() < 15);
+    }
+
+    info!("Test OK");
+    cortex_m::asm::bkpt();
+}
+
+use core::f32::consts::PI;
+
+use micromath::F32Ext;
+
+fn to_sine_wave(v: u8) -> u8 {
+    if v >= 128 {
+        // top half
+        let r = PI * ((v - 128) as f32 / 128.0);
+        (r.sin() * 128.0 + 127.0) as u8
+    } else {
+        // bottom half
+        let r = PI + PI * (v as f32 / 128.0);
+        (r.sin() * 128.0 + 127.0) as u8
+    }
+}

tests/stm32/src/common.rs

@@ -33,6 +33,7 @@ pub fn config() -> Config {
     {
         config.rcc.sys_ck = Some(Hertz(400_000_000));
         config.rcc.pll1.q_ck = Some(Hertz(100_000_000));
+        config.rcc.adc_clock_source = embassy_stm32::rcc::AdcClockSource::PerCk;
     }
 
     #[cfg(feature = "stm32u585ai")]