diff --git a/firmware/common/hackrf_core.h b/firmware/common/hackrf_core.h
index 18575759..c2e029d7 100644
--- a/firmware/common/hackrf_core.h
+++ b/firmware/common/hackrf_core.h
@@ -29,6 +29,8 @@ extern "C"
 {
 #endif
 
+#include <stdint.h>
+
 /* hardware identification number */
 #define BOARD_ID_JELLYBEAN 0
 
@@ -154,6 +156,8 @@ extern "C"
 /* TODO add other Pins */
 #endif
 
+void delay(uint32_t duration);
+
 void cpu_clock_init(void);
 void ssp1_init(void);
 void ssp1_set_mode_max2837(void);