diff --git a/libraries/AP_HAL/AnalogIn.h b/libraries/AP_HAL/AnalogIn.h
index 283983066c..40028815fa 100644
--- a/libraries/AP_HAL/AnalogIn.h
+++ b/libraries/AP_HAL/AnalogIn.h
@@ -15,5 +15,8 @@ public:
     virtual AP_HAL::AnalogSource* channel(int n) = 0;
 };
 
+#define ANALOG_INPUT_BOARD_VCC 254
+#define ANALOG_INPUT_NONE 255
+
 #endif // __AP_HAL_ANALOG_IN_H__