diff --git a/fw_test/main.c b/fw_test/main.c
index 5b3f951..e3ea38a 100644
--- a/fw_test/main.c
+++ b/fw_test/main.c
@@ -1,6 +1,7 @@
 #include <inttypes.h>
 #include <avr/io.h>
 #include <avr/interrupt.h>
+#define __DELAY_BACKWARD_COMPATIBLE__
 #include <util/delay.h>
 #include <stdlib.h>