Two ways to send two or more bytes with nrf_drv_twi_tx

RE: Two ways to send two or more bytes with nrf_drv_twi_tx

MartinBL — Tue, 09 Jan 2018 08:02:50 GMT

Thanks. I figured that maybe you were using the driver in non-blocking mode with an event handler. Then it wouldn't work to call two tx functions right after one another like you do in i2c_write_byte(). But obviously you use your code in blocking mode so that can't be the problem. Please get back to us when you have tested with a logic analyzer then.

RE: Two ways to send two or more bytes with nrf_drv_twi_tx

neosarchizo — Tue, 09 Jan 2018 07:38:42 GMT

@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;
}

RE: Two ways to send two or more bytes with nrf_drv_twi_tx

MartinBL — Tue, 09 Jan 2018 07:31:25 GMT

Can you also show us the code that you use for initializing the TWI driver?

RE: Two ways to send two or more bytes with nrf_drv_twi_tx

neosarchizo — Tue, 09 Jan 2018 01:13:13 GMT

@Rknguyen Now, I'm not able to debug two methods. But I will soon update about them! I will not use a scope, I will use a logic analyzer.

RE: Two ways to send two or more bytes with nrf_drv_twi_tx

RkNg — Sun, 07 Jan 2018 16:37:02 GMT

So,what you got when using these two methods? And what is on your scope ?

RE: Two ways to send two or more bytes with nrf_drv_twi_tx

neosarchizo — Sun, 07 Jan 2018 13:22:38 GMT

@rknguyen No, no!! I made typos. I modified this post. (data -> &data). I know how to check I2C data as you said. But the reason why I think so is that because nrf_drv_twi_tx function has no_stop parameter. The API docments said like following.

no_stop : If set, the stop condition is not generated on the bus after the transfer has completed successfully (allowing for a repeated start in the next transfer).

So, if I set no_stop to false, and recall nrf_drv_twi_tx function then only one transmission will occur.

I understood like this.

RE: Two ways to send two or more bytes with nrf_drv_twi_tx

RkNg — Sun, 07 Jan 2018 10:33:27 GMT

Hi, First, i think uint8_t tx_data[2] (1st function) is different from uint8_t data (2nd function), while the nrf_drv_twi_rx require "uint8_t *p_data". It would result in an incompatilble argument error when compiling

And, for I2C, I would suggest that you could use a scope to capture I2C data and see if there is any difference between these 2 functions.