diff --git a/targets/targets.json b/targets/targets.json
index 9c61672eb9..e93f8546d2 100644
--- a/targets/targets.json
+++ b/targets/targets.json
@@ -1503,6 +1503,7 @@
             "PORTINOUT",
             "PORTOUT",
             "PWMOUT",
+            "RESET_REASON",
             "SERIAL",
             "SERIAL_FC",
             "SERIAL_ASYNCH",