diff --git a/china_io-2019/avr/china-io-test.c b/china_io-2019/avr/china-io-test.c
index bb0f11424c49f535490cf41fe7b06ac5efbf876a..3373cdc89165b7f61003153f903a86eeb9309399 100644
--- a/china_io-2019/avr/china-io-test.c
+++ b/china_io-2019/avr/china-io-test.c
@@ -2,7 +2,6 @@
 #include <avr/io.h>
 #include <inttypes.h>
 #include <stdio.h>
-#include <util/twi.h>
 #include "i2c_master.h"
 
 #define DDR_SPI DDRB
diff --git a/china_io-2019/avr/i2c_master.h b/china_io-2019/avr/i2c_master.h
index 51ee51d54880779d7e227fc2b4230970b6abbe3b..85fc38525e5c993063b21bebd63c0c389d8a7c90 100644
--- a/china_io-2019/avr/i2c_master.h
+++ b/china_io-2019/avr/i2c_master.h
@@ -2,6 +2,7 @@
 #define __I2C_MASTER_H__
 
 #include <util/atomic.h>
+#include <util/twi.h>
 
 enum i2c_op {
   I2C_R_OP=0x01,