diff --git a/Makefile b/Makefile
index 5a2b577..2a2b28f 100644
--- a/Makefile
+++ b/Makefile
@@ -15,7 +15,8 @@ CFLAGS ?= -DWITH_ALT_LED9 -DWITHOUT_LEDTABLE_RELOC -DSHOW_TEMP_DATE_WEEKDAY
 
 LIBSRC = uart_init.c uart_send_chr.c uart_send_str.c \
 	 rotary_encoder_stat.c \
-	 sevenseg_dec.c sevenseg_dec_inv.c
+	 sevenseg_dec.c sevenseg_dec_inv.c \
+	 int_to_bcd.c
 
 LIBOBJ =$(patsubst %.c,%.rel, $(LIBSRC))
 LIBNAME=mc8051fun.lib