diff --git a/src/ADC/ADC.c b/src/ADC/ADC.c
index c926891..e441bf7 100644
--- a/src/ADC/ADC.c
+++ b/src/ADC/ADC.c
@@ -85,10 +85,7 @@ void ADC_Disable() {
   RegEdit_ClearBit((void *)&ADCSRA, ADEN);
 }
 
-uint16_t ADC_ReadValue_Impl(uint8_t adc_chan) {
-  if (IsInvalidChannel(adc_chan)) {
-    return UINT16_MAX;
-  }
+uint16_t ADC_ReadValue_Impl(void) {
 
   // start conversion.
   RegEdit_SetBit((void *)&ADCSRA, ADSC);
@@ -106,9 +103,9 @@ uint16_t ADC_ReadValue_Impl(uint8_t adc_chan) {
     cycles++;
   }
 
-  uint8_t val = ADC;
+  uint16_t val = ADC;
   return val;
 }
 
 // Set the default for the function pointer.
-uint16_t (*ADC_ReadValue)(uint8_t adc_chan) = ADC_ReadValue_Impl;
+uint16_t (*ADC_ReadValue)(void) = ADC_ReadValue_Impl;
diff --git a/src/ADC/ADC.h b/src/ADC/ADC.h
index 6ad30ab..bc64912 100644
--- a/src/ADC/ADC.h
+++ b/src/ADC/ADC.h
@@ -52,12 +52,11 @@ void ADC_Disable();
 /**
  * @brief Reads ADC value into variable
  *
- * @param adc_chan The bin number of the ADC pin being read.
  *
  * This function depends on the ADC already being initialized and enabled
  * before being called.
  */
-extern uint16_t (*ADC_ReadValue)(uint8_t adc_chan);
+extern uint16_t (*ADC_ReadValue)();
 
 /**
  * @brief Sets up the ADC