sw_i2c_write_byte
sw_i2c_write_byte(addr);
sw_i2c_write_byte(reg);
sw_i2c_write_byte(addr + 1);
if ((sw_i2c_write_byte(addr) != 0) ||
(sw_i2c_write_byte(reg) != 0) ||
(sw_i2c_write_byte(data) != 0)) {