Backport pull request #799

on-target-tests/tests/gpio.rs

@@ -100,4 +100,15 @@ mod tests {
             assert!(pac.PADS_BANK0.gpio(id).read().ie().bit_is_clear());
         }
     }
+
+    #[test]
+    fn read_adc() {
+        use embedded_hal_0_2::adc::OneShot;
+
+        // Safety: Test cases do not run in parallel
+        let mut pac = unsafe { pac::Peripherals::steal() };
+        let mut adc = hal::Adc::new(pac.ADC, &mut pac.RESETS);
+        let mut temp_sensor = hal::adc::Adc::take_temp_sensor(&mut adc).unwrap();
+        let _temperature: u16 = adc.read(&mut temp_sensor).unwrap();
+    }
 }

rp2040-hal/CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+- Fix oneshot adc read waiting indefinitely - #799 @mjptree
+
 ## [0.10.1] - 2024-04-28
 
 ### Added

rp2040-hal/src/adc.rs

@@ -404,12 +404,16 @@ impl Adc {
     ///
     /// Also returns immediately if start_many is set, to avoid indefinite blocking.
     pub fn wait_ready(&self) {
-        let cs = self.device.cs().read();
-        while !cs.ready().bit_is_set() && !cs.start_many().bit_is_set() {
+        while !self.is_ready_or_free_running() {
             cortex_m::asm::nop();
         }
     }
 
+    fn is_ready_or_free_running(&self) -> bool {
+        let cs = self.device.cs().read();
+        cs.ready().bit_is_set() || cs.start_many().bit_is_set()
+    }
+
     /// Returns true if the ADC is ready for the next conversion.
     ///
     /// This implies that any previous conversion has finished.