diff --git a/src/mraa.c b/src/mraa.c
index 5886396..765135d 100644
--- a/src/mraa.c
+++ b/src/mraa.c
@@ -263,7 +263,9 @@ mraa_pin_mode_test(int pin, mraa_pinmodes_t mode)
         case MRAA_PIN_UART:
             if (plat->pins[pin].capabilites.uart == 1)
                 return 1;
-        default: break;
+        default:
+            syslog(LOG_NOTICE, "requested pinmode invalid");
+            break;
     }
     return 0;
 }