diff --git a/soc/arm/atmel_sam0/samc20/soc.h b/soc/arm/atmel_sam0/samc20/soc.h
index 270f7557521..026479c31a5 100644
--- a/soc/arm/atmel_sam0/samc20/soc.h
+++ b/soc/arm/atmel_sam0/samc20/soc.h
@@ -52,6 +52,8 @@
 
 #endif /* _ASMLANGUAGE */
 
+#define ADC_SAM0_REFERENCE_ENABLE_PROTECTED
+
 #include "adc_fixup_sam0.h"
 #include "../common/soc_port.h"
 #include "../common/atmel_sam0_dt.h"
diff --git a/soc/arm/atmel_sam0/samc21/soc.h b/soc/arm/atmel_sam0/samc21/soc.h
index 9f245e8eb07..56e33169150 100644
--- a/soc/arm/atmel_sam0/samc21/soc.h
+++ b/soc/arm/atmel_sam0/samc21/soc.h
@@ -52,6 +52,8 @@
 
 #endif /* _ASMLANGUAGE */
 
+#define ADC_SAM0_REFERENCE_ENABLE_PROTECTED
+
 #include "adc_fixup_sam0.h"
 #include "../common/soc_port.h"
 #include "../common/atmel_sam0_dt.h"