diff --git a/interrupts/crc/lay1+2.c b/interrupts/crc/lay1+2.c
index a229ee36917d855c2c3f706ecb2017b8bd87fdcd..ebe88772449e2ec6be6898e2baa4a3de931fff2d 100644
--- a/interrupts/crc/lay1+2.c
+++ b/interrupts/crc/lay1+2.c
@@ -1,3 +1,9 @@
+#define F_CPU 12000000UL
+#define BAUD 9600
+
+#include <avr/io.h>
+#include <stdio.h>
+#include <util/setbaud.h>
 
 #include <stdlib.h>
 #include <stdint.h>