diff --git a/libraries/AP_Baro/examples/AP_Baro_PX4_test/AP_Baro_PX4_test.pde b/libraries/AP_Baro/examples/AP_Baro_PX4_test/AP_Baro_PX4_test.pde
index 0eaa871ca4..eb94aecca9 100644
--- a/libraries/AP_Baro/examples/AP_Baro_PX4_test/AP_Baro_PX4_test.pde
+++ b/libraries/AP_Baro/examples/AP_Baro_PX4_test/AP_Baro_PX4_test.pde
@@ -4,6 +4,7 @@
 #include <AP_Param.h>
 #include <AP_Math.h>
 #include <AP_HAL.h>
+#include <AP_HAL_AVR.h>
 #include <AP_HAL_PX4.h>
 #include <AP_HAL_Empty.h>
 #include <AP_Buffer.h>