diff --git a/cpu/stm32f1/Makefile.features b/cpu/stm32f1/Makefile.features
index 5e5e8b9118b4..20b5c5564d6c 100644
--- a/cpu/stm32f1/Makefile.features
+++ b/cpu/stm32f1/Makefile.features
@@ -1,4 +1,8 @@
 FEATURES_PROVIDED += periph_flashpage
 FEATURES_PROVIDED += periph_flashpage_raw
+FEATURES_PROVIDED += periph_rtc
+
+FEATURES_CONFLICT += periph_rtc:periph_rtt
+FEATURES_CONFLICT_MSG += "On the STM32F1, the RTC and RTT map to the same hardware peripheral."
 
 -include $(RIOTCPU)/stm32_common/Makefile.features