diff --git a/Makefile b/Makefile
index 5f981f0..9fc718d 100644
--- a/Makefile
+++ b/Makefile
@@ -31,7 +31,7 @@ DEBUG = stabs
 CSTANDARD = -std=gnu99
 
 # Place -D or -U options here
-CDEFS = -DF_CPU=1000000L -D__AVR__ -D__AVR_ATmega328P__
+CDEFS = -DF_CPU=16000000L -D__AVR__ -D__AVR_ATmega328P__
 
 # Place -I options here
 CINCS = -I $(INC_DIR)
diff --git a/src/main.c b/src/main.c
index e9623a7..4a2bd38 100644
--- a/src/main.c
+++ b/src/main.c
@@ -12,11 +12,6 @@
 #include "debug.h"
 #endif /* DEBUG */
 
-#ifndef F_CPU
-#define F_CPU 1000000UL // Stock atmega328p
-#endif
-
-
 void read_temp(void)
 {
     double d;