diff --git a/c/common/i2cdriver.h b/c/common/i2cdriver.h
index 9b0c04e..79f8675 100644
--- a/c/common/i2cdriver.h
+++ b/c/common/i2cdriver.h
@@ -32,6 +32,7 @@ void i2c_connect(I2CDriver *sd, const char* portname);
 void i2c_getstatus(I2CDriver *sd);
 int  i2c_write(I2CDriver *sd, const uint8_t bytes[], size_t nn);
 void i2c_read(I2CDriver *sd, uint8_t bytes[], size_t nn);
+int  i2c_start(I2CDriver *sd, uint8_t dev, uint8_t op);
 void i2c_stop(I2CDriver *sd);
 
 void i2c_monitor(I2CDriver *sd, int enable);