diff --git a/src/Makefile b/src/Makefile
index 3845f3e..456af1b 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -6,7 +6,7 @@ TARGET=led-controller
 CC=avr-gcc
 OBJDUMP=avr-objdump
 OBJCOPY=avr-objcopy
-CFLAGS=-g -Wall -O3 -std=c99
+CFLAGS=-g -Werror -O3 -std=c99
 # the target
 DEVICE=atmega328p
 F_CPU=18432000UL