How to read the value from ADC

[Nils Minor]

Hi,

i want to use the adc, i use the code from here devzone.nordicsemi.com/.../is-there-an-example-code-for-using-pwm-on-the-nrf51822-with-a-softdevice and it works fine. But i don#t know how to handle the ->Result when i got 5 ADC Channels to use. It would be great if some one can tell me how to use ->Result and how to confert it to some variables

best regards Nils

[Sébastien Despont]

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;		
}

[KETAN_PATEL]

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