How to read the value from ADC

RE: How to read the value from ADC

KETAN_PATEL — Wed, 11 Oct 2017 07:04:44 GMT

for this example no need to connect any of analog pin to VDD or VCC??

RE: How to read the value from ADC

Gilson — Sat, 08 Nov 2014 17:09:02 GMT

https://github.com/NordicSemiconductor/nrf51-ADC-examples

RE: How to read the value from ADC

Stefan Birnir Sverrisson — Fri, 03 Oct 2014 07:24:11 GMT

You are welcome. Please vote for the answers that you find helpful.

RE: How to read the value from ADC

jonf — Thu, 02 Oct 2014 19:53:04 GMT

Stefan's solution worked very well. I just implemented it with no troubles. Thank you very much.

RE: How to read the value from ADC

Stefan Birnir Sverrisson — Tue, 03 Jun 2014 18:35:16 GMT

some ADC examples are now available here on Gibhub github.com/.../nrf51-ADC-examples

RE: How to read the value from ADC

Wayne — Tue, 27 May 2014 12:20:33 GMT

the link is broken,is the zip available somewhere else please?

RE: How to read the value from ADC

Nils Minor — Thu, 12 Sep 2013 11:40:22 GMT

Hi,

thank you for your help, but my code works now, after trying soem changing of my code :) Thanks

RE: How to read the value from ADC

Stefan Birnir Sverrisson — Thu, 12 Sep 2013 10:12:00 GMT

Hi Nils

Sorry for my late entrance into this thread. I have attached an ADC example code that is perhaps more relevant for your purpose. It samples from two different ADC input pins and stores the result in two different variables. It is tested with the nRF51822 development kit and SDK 4.3

adc_example_from_AIN_8bit_10bit.zip

RE: How to read the value from ADC

Nils Minor — Mon, 02 Sep 2013 05:47:30 GMT

Ahh ok thank you

RE: How to read the value from ADC

Ole Morten — Fri, 30 Aug 2013 07:59:32 GMT

You won't normally get a quicker answer by posting several replies (that aren't actual replies, but just bumping) to your own question. We try to tend to all questions here as we have time, but some days are more busy than others. Posting a complete, clear question, with detailed description on what you need to do, what exactly is the problem, and what you've already tried is the best way to get a quick reply.

RE: How to read the value from ADC

Ole Morten — Fri, 30 Aug 2013 07:56:33 GMT

The ADC will measure one input at a time, so depending on which input was selected in PSEL when you started the measurement, the RESULT when you get the END event will be the result for this particular input. No special handling of this should be needed; if you need to measure 5 different inputs, you'll just have to cycle through them.

RE: How to read the value from ADC

Nils Minor — Fri, 30 Aug 2013 06:09:36 GMT

Can anyone explain to me how to handle the RESULT pls?

thanks Nils

RE: How to read the value from ADC

Nils Minor — Thu, 29 Aug 2013 12:18:35 GMT

Hi, thanks for the answer.

Mhh i don't get it with this code. You also handle only one adc mesurement (adc_result), but i need to handle 5 mesurements from the ADCs but i don#t understand how to use ->ADC_RESULT

thank you, Nils

RE: How to read the value from ADC

Sébastien Despont — Thu, 29 Aug 2013 06:51:11 GMT

Here is an example of ADC reading value :

/**@brief ADC interrupt handler.
 * @details  This function will fetch the conversion result from the ADC, convert the value into
 *           percentage and send it to peer.
 */
void ADC_IRQHandler(void)
{
    if (NRF_ADC->EVENTS_END != 0)
    {
        uint8_t     adc_result;
        uint16_t    batt_lvl_in_milli_volts;
        uint8_t     batt_lvl_formatted;			
        uint8_t     percentage_batt_lvl;
        uint32_t    err_code;

        NRF_ADC->EVENTS_END     = 0;
        adc_result              = NRF_ADC->RESULT;
        NRF_ADC->TASKS_STOP     = 1;

        batt_lvl_in_milli_volts = ADC_RESULT_IN_MILLI_VOLTS(adc_result) ;//+ DIODE_FWD_VOLT_DROP_MILLIVOLTS;
        percentage_batt_lvl     = battery_level_in_percent(batt_lvl_in_milli_volts);
				
			  batt_lvl_formatted = batt_lvl_in_milli_volts/100;
			
			  if (batt_lvl_formatted != m_bas.battery_level_last)
        {
					uint16_t len = sizeof(uint8_t);
					
					// Save new battery value
					m_bas.battery_level_last = batt_lvl_formatted;
					
					// Update database
					err_code = sd_ble_gatts_value_set(m_bas.battery_level_handles.value_handle,
																						0,
																						&len,
																						&batt_lvl_formatted);					
				}
        err_code = ble_bas_battery_level_update(&m_bas, percentage_batt_lvl);
        if (
            (err_code != NRF_SUCCESS)
            &&
            (err_code != NRF_ERROR_INVALID_STATE)
            &&
            (err_code != BLE_ERROR_NO_TX_BUFFERS)
            &&
            (err_code != BLE_ERROR_GATTS_SYS_ATTR_MISSING)
        )
        {
            APP_ERROR_HANDLER(err_code);
        }
    }
}


/**@brief Function to make the ADC start a battery level conversion.
 */
static void adc_start(void)
{
    uint32_t err_code;

    // Configure ADC
    NRF_ADC->INTENSET   = ADC_INTENSET_END_Msk;
    NRF_ADC->CONFIG     = (ADC_CONFIG_RES_8bit                        << ADC_CONFIG_RES_Pos)     |
                          (ADC_CONFIG_INPSEL_SupplyOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos)  |
                          (ADC_CONFIG_REFSEL_VBG                      << ADC_CONFIG_REFSEL_Pos)  |
                          (ADC_CONFIG_PSEL_Disabled                   << ADC_CONFIG_PSEL_Pos)    |
                          (ADC_CONFIG_EXTREFSEL_None                  << ADC_CONFIG_EXTREFSEL_Pos);
    NRF_ADC->EVENTS_END = 0;
    NRF_ADC->ENABLE     = ADC_ENABLE_ENABLE_Enabled;

    // Enable ADC interrupt
    err_code = sd_nvic_ClearPendingIRQ(ADC_IRQn);
    APP_ERROR_CHECK(err_code);

    err_code = sd_nvic_SetPriority(ADC_IRQn, NRF_APP_PRIORITY_LOW);
    APP_ERROR_CHECK(err_code);

    err_code = sd_nvic_EnableIRQ(ADC_IRQn);
    APP_ERROR_CHECK(err_code);

    NRF_ADC->EVENTS_END  = 0;    // Stop any running conversions.
    NRF_ADC->TASKS_START = 1;		
}