diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
index 77f5b85e17..a3ea17ea75 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
@@ -152,10 +152,6 @@
 #define AP_RELAY_ENABLED 0
 #endif
 
-#ifndef AP_RTC_ENABLED
-#define AP_RTC_ENABLED 0
-#endif
-
 /*
  * GPS Backends - we selectively turn backends on.
  *   Note also that f103-GPS explicitly disables some of these backends.
@@ -324,6 +320,7 @@
 #define AP_GPS_ENABLED 1  // FIXME: should be defined(HAL_PERIPH_ENABLE_GPS)
 #define AP_RPM_ENABLED defined(HAL_PERIPH_ENABLE_RPM)
 #define AP_RCPROTOCOL_ENABLED defined(HAL_PERIPH_ENABLE_RCIN)
+#define AP_RTC_ENABLED defined(HAL_PERIPH_ENABLE_RTC)
 
 #ifndef AP_BOOTLOADER_ALWAYS_ERASE
 #define AP_BOOTLOADER_ALWAYS_ERASE 1