diff --git a/portable/ThirdParty/GCC/ATmega/port.c b/portable/ThirdParty/GCC/ATmega/port.c
index 827794985..f998cdb28 100644
--- a/portable/ThirdParty/GCC/ATmega/port.c
+++ b/portable/ThirdParty/GCC/ATmega/port.c
@@ -61,6 +61,8 @@
     #define portTIMSK                   TIMSK0
     #define portTIFR                    TIFR0
 
+#else
+    #error "No Timer defined for scheduler"
 #endif
 
 /*-----------------------------------------------------------*/