initial support for STM32G4 ADC

examples/stm32g4/src/bin/adc.rs

@@ -0,0 +1,41 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+use defmt::*;
+use embassy_executor::Spawner;
+use embassy_stm32::adc::{Adc, SampleTime};
+use embassy_stm32::rcc::{AdcClockSource, ClockSrc, Pll, PllM, PllN, PllR, PllSrc};
+use embassy_stm32::Config;
+use embassy_time::{Delay, Duration, Timer};
+use {defmt_rtt as _, panic_probe as _};
+
+#[embassy_executor::main]
+async fn main(_spawner: Spawner) {
+    let mut config = Config::default();
+
+    config.rcc.pll = Some(Pll {
+        source: PllSrc::HSI16,
+        prediv_m: PllM::Div4,
+        mul_n: PllN::Mul85,
+        div_p: None,
+        div_q: None,
+        // Main system clock at 170 MHz
+        div_r: Some(PllR::Div2),
+    });
+
+    config.rcc.adc12_clock_source = AdcClockSource::SysClk;
+    config.rcc.mux = ClockSrc::PLL;
+
+    let mut p = embassy_stm32::init(config);
+    info!("Hello World!");
+
+    let mut adc = Adc::new(p.ADC2, &mut Delay);
+    adc.set_sample_time(SampleTime::Cycles32_5);
+
+    loop {
+        let measured = adc.read(&mut p.PA7);
+        info!("measured: {}", measured);
+        Timer::after(Duration::from_millis(500)).await;
+    }
+}