diff --git a/apis/peripherals/adc/src/lib.rs b/apis/peripherals/adc/src/lib.rs
index c7406574..1229dfb0 100644
--- a/apis/peripherals/adc/src/lib.rs
+++ b/apis/peripherals/adc/src/lib.rs
@@ -23,8 +23,10 @@ impl<S: Syscalls> Adc<S> {
             .and(Ok(()))
     }
     //Returns the number of channels
-    pub fn get_number_of_channels() -> Result<u32, ErrorCode> {
-        S::command(DRIVER_NUM, EXISTS, 0, 0).to_result::<u32, ErrorCode>()
+    pub fn get_number_of_channels() -> Result<usize, ErrorCode> {
+        S::command(DRIVER_NUM, EXISTS, 0, 0)
+            .to_result::<u32, ErrorCode>()
+            .and_then(|number_channels| number_channels.try_into().map_err(|_| ErrorCode::Fail))
     }
 
     // Initiate a sample reading
diff --git a/apis/peripherals/adc/src/tests.rs b/apis/peripherals/adc/src/tests.rs
index d27ebc2a..80026c92 100644
--- a/apis/peripherals/adc/src/tests.rs
+++ b/apis/peripherals/adc/src/tests.rs
@@ -25,11 +25,13 @@ fn read_single_sample() {
     let driver = fake::Adc::new();
     kernel.add_driver(&driver);
 
-    assert_eq!(Adc::read_single_sample(), Ok(()));
+    let ch = Adc::get_number_of_channels().unwrap();
+
+    assert_eq!(Adc::read_single_sample(ch), Ok(()));
     assert!(driver.is_busy());
 
-    assert_eq!(Adc::read_single_sample(), Err(ErrorCode::Busy));
-    assert_eq!(Adc::read_single_sample_sync(), Err(ErrorCode::Busy));
+    assert_eq!(Adc::read_single_sample(ch), Err(ErrorCode::Busy));
+    assert_eq!(Adc::read_single_sample_sync(ch), Err(ErrorCode::Busy));
 }
 
 #[test]
@@ -43,18 +45,20 @@ fn register_unregister_listener() {
         sample.set(Some(adc_val));
     });
     share::scope(|subscribe| {
-        assert_eq!(Adc::read_single_sample(), Ok(()));
+        let ch = Adc::get_number_of_channels().unwrap();
+
+        assert_eq!(Adc::read_single_sample(ch), Ok(()));
         driver.set_value(100);
         assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::NoUpcall);
 
         assert_eq!(Adc::register_listener(&listener, subscribe), Ok(()));
-        assert_eq!(Adc::read_single_sample(), Ok(()));
+        assert_eq!(Adc::read_single_sample(ch), Ok(()));
         driver.set_value(100);
         assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::Upcall);
         assert_eq!(sample.get(), Some(100));
 
         Adc::unregister_listener();
-        assert_eq!(Adc::read_single_sample(), Ok(()));
+        assert_eq!(Adc::read_single_sample(ch), Ok(()));
         driver.set_value(100);
         assert_eq!(fake::Syscalls::yield_no_wait(), YieldNoWaitReturn::NoUpcall);
     });
@@ -66,6 +70,8 @@ fn read_single_sample_sync() {
     let driver = fake::Adc::new();
     kernel.add_driver(&driver);
 
+    let ch = Adc::get_number_of_channels().unwrap();
+
     driver.set_value_sync(1000);
-    assert_eq!(Adc::read_single_sample_sync(), Ok(1000));
+    assert_eq!(Adc::read_single_sample_sync(ch), Ok(1000));
 }