diff --git a/cpu/samd21/include/periph_cpu.h b/cpu/samd21/include/periph_cpu.h
index f05902506f..fa31cf5834 100644
--- a/cpu/samd21/include/periph_cpu.h
+++ b/cpu/samd21/include/periph_cpu.h
@@ -28,6 +28,12 @@
 extern "C" {
 #endif
 
+/**
+ * @brief   Override the default initial PM blocker
+ * @todo   Idle modes are enabled by default, deep sleep mode blocked
+ */
+#define PM_BLOCKER_INITIAL  { .val_u32 = 0x00000001 }
+
 /**
  * @brief   Mapping of pins to EXTI lines, -1 means not EXTI possible
  */