diff --git a/cpu/atmega32u4/global.make b/cpu/atmega32u4/global.make
index ac5860e..c20ccc7 100755
--- a/cpu/atmega32u4/global.make
+++ b/cpu/atmega32u4/global.make
@@ -2,6 +2,7 @@ COMPILER_PREFIX=avr-
 CFLAGS+=-ggdb -mmcu=atmega32u4 -Wall -Os
 ASFLAGS+=-ggdb -mmcu=atmega32u4
 LDFLAGS+=-ggdb -mmcu=atmega32u4
+AVR_MCU=m32u4