sampling two analog

[lyrics]

Hello

I want to sampling two analog.. with different configuration and handler.

so I set two channels like this.

    nrf_saadc_channel_config_t cds_channel_config =
    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

    err_code = nrf_drv_saadc_init(&cds_saadc_config, cds_saadc_callback);
    if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_channel_init(0, &cds_channel_config);
    if(err_code != NRF_SUCCESS) return 1;
    
    ///////////////////////////////// (different function)
    
    nrf_saadc_channel_config_t co_channel_config =
    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN6);

    err_code = nrf_drv_saadc_init(&co_saadc_config, co_saadc_callback);
    if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_channel_init(1, &co_channel_config);
    if(err_code != NRF_SUCCESS) return 1;

and then I call only one sample function like this.

void saadc_process()
{
    //..

    nrf_drv_saadc_sample();
}

Then error occurs. How can I change code?

and is there good example I can refer?

BR,

lyrics

[Jared]

Hi,

Exactly what error occurs?

The SAADC periperhal should only be initialized once with the same nrfx_saadc_config_t configuration.

You can un-initialize it and then re-initialize with a new configuration. Is there any difference between cds_saadc_config and co_saadc_config? 

The channels can be configured differently so this shouldn't be a problem.

regards

Jared 

[lyrics]

Jared said:

Exactly what error occurs?

it returns 0x08 error , second initializing.

 err_code = nrf_drv_saadc_init(&co_saadc_config, co_saadc_callback);

Jared said:

Is there any difference between cds_saadc_config and co_saadc_config? 

they are different sensor, so each sensor value needs to sampling.

[lyrics]

Hi,

Jared said:

Maybe it would be better to just use 10 bits in both cases,

First of all, I just added a channel and ran the program..

But error occurs second channel init function.. (nrf_drv_saadc_channel_init)

 I hope there is reference code (example)!

    ret_code_t err_code;
    nrf_drv_saadc_config_t cds_saadc_config;

    cds_saadc_config.low_power_mode = false;                                  //Enable low power mode.
    cds_saadc_config.resolution = NRF_SAADC_RESOLUTION_8BIT;                  //Set SAADC resolution to 12-bit. This will make the SAADC output values from 0 (when input voltage is 0V) to 2^12=4096 (when input voltage is 3.6V for channel gain setting of 1/6).
    cds_saadc_config.oversample = NRF_SAADC_OVERSAMPLE_DISABLED;              //Set oversample to 4x. This will make the SAADC output a single averaged value when the SAMPLE task is triggered 4 times.
    cds_saadc_config.interrupt_priority = APP_IRQ_PRIORITY_LOW;               //Set SAADC interrupt to low priority.

    nrf_saadc_channel_config_t cds_channel_config =
    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

    err_code = nrf_drv_saadc_init(&cds_saadc_config, cds_saadc_callback);
    if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_channel_init(0, &cds_channel_config);
    if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_buffer_convert(m_cds_buffer_pool[0], 1);
    APP_ERROR_CHECK(err_code);
    
    err_code = nrf_drv_saadc_buffer_convert(m_cds_buffer_pool[1], 1);
    APP_ERROR_CHECK(err_code);
    
    nrf_saadc_channel_config_t co_channel_config =
    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN6);

    err_code = nrf_drv_saadc_channel_init(1, &co_channel_config );
    APP_ERROR_CHECK(err_code);
    
    err_code = nrf_drv_saadc_buffer_convert(m_co_buffer_pool[0], 1);
    APP_ERROR_CHECK(err_code);
    
    err_code = nrf_drv_saadc_buffer_convert(m_co_buffer_pool[1], 1);
    APP_ERROR_CHECK(err_code);
    
    //CDS_F=1;
    return 0;

[Jared]

lyrics said:

But error occurs second channel init function.. (nrf_drv_saadc_channel_init)

 OK, but this is a different function than earlier. What error code is returned?

regards

Jared 

[lyrics]

Hi,

Jared said:

OK, but this is a different function than earlier. What error code is returned?

In that case, the err_code is 0x11 (17).

However, if I move on to the next function with the break point, the error below occurs.

[lyrics]

Hi, I fixed the issue.. But another question.

I reference this github code, and followed the code like this.

    nrf_saadc_channel_config_t cds_channel_config =
    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN1);

    cds_channel_config.gain = NRF_SAADC_GAIN1;

    nrf_saadc_channel_config_t co_channel_config =
    NRF_DRV_SAADC_DEFAULT_CHANNEL_CONFIG_SE(NRF_SAADC_INPUT_AIN6);

    co_channel_config.gain = NRF_SAADC_GAIN1;

    err_code = nrf_drv_saadc_init(&cds_saadc_config, cds_saadc_callback);
    if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_channel_init(0, &cds_channel_config);
    APP_ERROR_CHECK(err_code);
    if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_channel_init(1, &co_channel_config );
    APP_ERROR_CHECK(err_code);
    //if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_buffer_convert(m_cds_buffer_pool[0], 1);
    APP_ERROR_CHECK(err_code);
    //if(err_code != NRF_SUCCESS) return 1;

    err_code = nrf_drv_saadc_buffer_convert(m_cds_buffer_pool[1], 1);
    APP_ERROR_CHECK(err_code);

and then it works well, but the result of data are not what I expected.

So, what is role of SAADC_CH_CONFIG_GAIN_Gain1_4 and  SAADC_CH_CONFIG_REFSEL_VDD1_4 ?

[Jared]

lyrics said:

So, what is role of SAADC_CH_CONFIG_GAIN_Gain1_4 and  SAADC_CH_CONFIG_REFSEL_VDD1_4 ?

They are the configured Gain and Reference that is used during the sampling. Please read the product specification regarding this topic, and consider making a new ticket for future problems as the original problem has been solved.

regards

Jared