Two ways to send two or more bytes with nrf_drv_twi_tx

[neosarchizo]

Hi! I use ICM-20602 motion sensor that is similar to MPU6050. Its communication type is also I2C.

I made I2C wrapping module for ICM-20602. In the module, I added i2c_write_byte and i2c_write_bytes functions like following code.

ret_code_t i2c_write_byte(uint8_t dev_addr, uint8_t reg_addr, uint8_t data) 
{
    ret_code_t err_code;
    uint8_t tx_data[2] = { reg_addr, data };

    return nrf_drv_twi_tx(&m_twi_master, dev_addr, tx_data, 2, false);
}

But i2c_write_byte was not like this code. i2c_write_byte was like following code.

ret_code_t i2c_write_byte(uint8_t dev_addr, uint8_t reg_addr, uint8_t data) 
{
    ret_code_t err_code;

    err_code = nrf_drv_twi_tx(&m_twi_master, dev_addr, &reg_addr, 1, true);
    if (err_code != NRF_SUCCESS) return err_code;
    
    err_code = nrf_drv_twi_tx(&m_twi_master, dev_addr, &data, 1, false);
    
    return err_code;
}

But this old i2c_write_byte function did not work well. I think that operations of these i2c_write_byte functions must be an exact match. I read and read again API documents. But results of these i2c_write_byte functions are different. I don't know why. Please explain why results of these i2c_write_byte functions are different.

[neosarchizo]

@martinbl Here it is! Please ignore macro function.

ret_code_t i2c_init(){

#if NEOSARCHIZO_DEBUG == 1
    NRF_LOG_INFO("i2c_init : start");
#endif

    ret_code_t err_code;
    const nrf_drv_twi_config_t config =
    {
       .scl                = I2C_SCL_M,
       .sda                = I2C_SDA_M,
       .frequency          = NRF_TWI_FREQ_400K,
       .interrupt_priority = APP_IRQ_PRIORITY_LOW,
       .clear_bus_init     = false
    };
    
#if NEOSARCHIZO_DEBUG == 1
    NRF_LOG_INFO("i2c_init : nrf_drv_twi_init");
#endif

    err_code = nrf_drv_twi_init(&m_twi_master, &config, NULL, NULL);
    APP_ERROR_CHECK(err_code);

#if NEOSARCHIZO_DEBUG == 1
    NRF_LOG_INFO("i2c_init : nrf_drv_twi_enable");
#endif

    nrf_drv_twi_enable(&m_twi_master);

#if NEOSARCHIZO_DEBUG == 1
    NRF_LOG_INFO("i2c_init : end");
#endif

    return err_code;
}