diff --git a/libraries/AP_HAL/AnalogIn.h b/libraries/AP_HAL/AnalogIn.h
index 383d4a2a4f..5afe612b8d 100644
--- a/libraries/AP_HAL/AnalogIn.h
+++ b/libraries/AP_HAL/AnalogIn.h
@@ -2,6 +2,8 @@
 #ifndef __AP_HAL_ANALOG_IN_H__
 #define __AP_HAL_ANALOG_IN_H__
 
+#include <inttypes.h>
+
 #include "AP_HAL_Namespace.h"
 
 class AP_HAL::AnalogSource {