diff --git a/src/ADC/ADC.c b/src/ADC/ADC.c
index dc8eda0..86d993b 100644
--- a/src/ADC/ADC.c
+++ b/src/ADC/ADC.c
@@ -13,11 +13,13 @@
 #include "RegEdit.h"
 #include "avr/io.h"
 
+#define MAX_PIN_NUM 7
+
 static uint8_t porta_out;
 static uint8_t porta_dir;
 
 static bool IsInvalidPin(uint8_t pin_num){
-    if(pin_num > 7){
+    if(pin_num > MAX_PIN_NUM){
         return true;
     }
     return false;
@@ -97,6 +99,12 @@ void ADC_Disable()
 }
 
 
+void ADC_SetPin(uint8_t pin_num)
+{
+    RegEdit_ClearRegister((void *) &ADC0.MUXPOS);
+    RegEdit_SetNum((void *) &ADC0.MUXPOS, pin_num);
+}
+
 uint16_t ADC_ReadValue_Impl(uint8_t pin_num)
 {
     RegEdit_SetNum((void *) &ADC0.COMMAND, ADC_STCONV_bm);
diff --git a/src/ADC/ADC.h b/src/ADC/ADC.h
index b3a7118..d5578d6 100644
--- a/src/ADC/ADC.h
+++ b/src/ADC/ADC.h
@@ -65,4 +65,11 @@ extern uint16_t (*ADC_ReadValue)(uint8_t pin_num);
 void ADC_Setup(void);     
 
 
+/**
+ * @brief Sets the pin used in the MUX for ADC0.
+ *
+ * @param pin_num The number of the pin in Port A.
+ */
+void ADC_SetPin(uint8_t pin_num);
+
 #endif //ADC_H   
diff --git a/tests/ADC/test_ADC.cpp b/tests/ADC/test_ADC.cpp
index e6316bf..494c467 100644
--- a/tests/ADC/test_ADC.cpp
+++ b/tests/ADC/test_ADC.cpp
@@ -182,6 +182,19 @@ TEST(test_ADC, ADC_DisablePasses)
     ADC_Disable();
 }
 
+TEST(test_ADC, ADC_SetPinSetsRightRegisters)
+{
+    //It clears existing MUXPOS register values.
+    mock().expectOneCall("RegEdit_ClearRegister")
+        .withPointerParameter("reg", (void *) &ADC0.MUXPOS);
+
+    //It Correctly sets the pin number.
+    mock().expectOneCall("RegEdit_SetNum")
+        .withPointerParameter("reg", (void *) &ADC0.MUXPOS)
+        .withUnsignedIntParameter("num", 4);
+
+    ADC_SetPin(4);
+}
 
 
 static uint16_t ADC_ReadValueFake(uint8_t pin_num)