ausmbus_write_byte
static int ausmbus_write_byte(void *arg, uint8_t v, int flags);
error = ausmbus_write_byte(sc, cmd, I2C_F_READ);
error = ausmbus_write_byte(sc, cmd, I2C_F_READ);
error = ausmbus_write_byte(sc, val, I2C_F_STOP);
error = ausmbus_write_byte(sc, cmd, 0);
error = ausmbus_write_byte(sc, val, I2C_F_STOP);
error = ausmbus_write_byte(sc, cmd, 0);
error = ausmbus_write_byte(sc, low, 0);
error = ausmbus_write_byte(sc, high, I2C_F_STOP);