1 files changed, 3 insertions, 0 deletions
diff --git a/include.mk b/include.mk
index 66daa10..19afa95 100644
--- a/include.mk
+++ b/include.mk
@@ -24,6 +24,9 @@ ifndef SPREADAVR_PATH
 SPREADAVR_PATH := ..
 endif
 include $(SPREADAVR_PATH)/defines.mk
+ifndef MCU
+$(error Unknown board: '$(BOARD_TYPE)')
+endif
 
 ## project-specific objects
 SRC := $(OBJ:%.o=%.c)