diff --git a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat
index d719b80c10..ca6a6c919f 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-F9P/hwdef.dat
@@ -122,7 +122,7 @@ define GPS_MOVING_BASELINE 1
 
 # Logging
 define HAL_LOGGING_ENABLED 1
-define HAL_PERIPH_ENABLE_RTC 1
+define AP_PERIPH_RTC_ENABLED 1
 define HAL_OS_FATFS_IO 1
 
 # SD Card pins
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-PrecisionPoint/hwdef.dat b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-PrecisionPoint/hwdef.dat
index c789bc5a4f..b7f618c7f3 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/Sierra-PrecisionPoint/hwdef.dat
+++ b/libraries/AP_HAL_ChibiOS/hwdef/Sierra-PrecisionPoint/hwdef.dat
@@ -125,7 +125,7 @@ define GPS_MAX_RATE_MS 200
 
 # Logging
 define HAL_LOGGING_ENABLED 1
-define HAL_PERIPH_ENABLE_RTC 1
+define AP_PERIPH_RTC_ENABLED 1
 define HAL_OS_FATFS_IO 1
 
 # SD Card pins
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/include/network_PPPGW.inc b/libraries/AP_HAL_ChibiOS/hwdef/include/network_PPPGW.inc
index b38e455947..345fb736cb 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/include/network_PPPGW.inc
+++ b/libraries/AP_HAL_ChibiOS/hwdef/include/network_PPPGW.inc
@@ -1,7 +1,7 @@
 undef AP_RC_CHANNEL_ENABLED
 define AP_RC_CHANNEL_ENABLED 0
 
-define HAL_PERIPH_ENABLE_RTC
+define AP_PERIPH_RTC_ENABLED 1
 
 define HAL_PERIPH_ENABLE_SERIAL_OPTIONS
 define AP_NETWORKING_BACKEND_PPP 1
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
index a50540e943..35b2164def 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/scripts/defaults_periph.h
@@ -184,6 +184,9 @@
 #ifdef HAL_PERIPH_ENABLE_IMU
 #error "Change 'define HAL_PERIPH_ENABLE_IMU' to 'define AP_PERIPH_IMU_ENABLED 1'"
 #endif
+#ifdef HAL_PERIPH_ENABLE_RTC
+#error "Change 'define HAL_PERIPH_ENABLE_RTC' to 'define AP_PERIPH_RTC_ENABLED 1'"
+#endif
 
 /*
  * defaults for various AP_Periph features:
@@ -212,6 +215,9 @@
 #ifndef AP_PERIPH_IMU_ENABLED
 #define AP_PERIPH_IMU_ENABLED 0
 #endif
+#ifndef AP_PERIPH_RTC_ENABLED
+#define AP_PERIPH_RTC_ENABLED 0
+#endif
 
 /*
  * turning on of ArduPilot features based on which AP_Periph features
@@ -225,6 +231,7 @@
 #define AP_RANGEFINDER_ENABLED AP_PERIPH_RANGEFINDER_ENABLED
 #define AP_INERTIALSENSOR_ENABLED AP_PERIPH_IMU_ENABLED
 #define AP_INERTIALSENSOR_ALLOW_NO_SENSORS AP_PERIPH_IMU_ENABLED
+#define AP_RTC_ENABLED AP_PERIPH_RTC_ENABLED
 
 /*
  * GPS Backends - we selectively turn backends on.
@@ -416,7 +423,6 @@
 
 #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)
 #define AP_INERTIALSENSOR_HARMONICNOTCH_ENABLED 0
 
 #ifndef AP_BOOTLOADER_ALWAYS_ERASE