How to Read 16 bit ADC Value on nRF Master app? not 8 bit!

[FormerMember]

Hello!

I'm trying to read 16 bit ADC Value on nRF Master app instead of only 8 bit, and I know that there is the example code on github which is only send me the 8 bit "uint8_t adc_result" data to nRF mater app

/* Interrupt handler for ADC data ready event */
void ADC_IRQHandler(void)
{
	uint8_t adc_result;
	
	/* Clear dataready event */
  NRF_ADC->EVENTS_END = 0;	

  /* Write ADC result both to the UART and over BLE */
	adc_result = NRF_ADC->RESULT;
	app_uart_put(adc_result);
	ble_nus_send_string(&m_nus, &adc_result, 1);
	nrf_gpio_pin_toggle(LED_3);        //indicate on LED that the ADC interrupt handler is executing
	
	//Use the STOP task to save current. Workaround for PAN_028 rev1.5 anomaly 1.
  NRF_ADC->TASKS_STOP = 1;
	
	//Release the external crystal
	sd_clock_hfclk_release();
}	

where it sends the ADC value over Bluetooth by the "ble_nus_send_string()" command:

uint32_t ble_nus_send_string(ble_nus_t * p_nus, uint8_t * string, uint16_t length)
{
    ble_gatts_hvx_params_t hvx_params;

    if (p_nus == NULL)
    {
        return NRF_ERROR_NULL;
    }
    
    if ((p_nus->conn_handle == BLE_CONN_HANDLE_INVALID) || (!p_nus->is_notification_enabled))
    {
        return NRF_ERROR_INVALID_STATE;
    }
    
    if (length > BLE_NUS_MAX_DATA_LEN)
    {
        return NRF_ERROR_INVALID_PARAM;
    }
    
    memset(&hvx_params, 0, sizeof(hvx_params));

    hvx_params.handle = p_nus->rx_handles.value_handle;
    hvx_params.p_data = string;
    hvx_params.p_len  = &length;
    hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;
    
    return sd_ble_gatts_hvx(p_nus->conn_handle, &hvx_params);
}

if I just similarly change the 'uint8_t adc_result' to 'uint16_t adc_result' it will show me endless ERROR.

Does anyone have any solutions for reading the ADC value on the nRF Mater Control panel app 16 bits instead of only 8 bits?

Any help is appreciated!

[FormerMember]

ok,I'm sorry. I was a little bit of confuse. so do you mean that your code above:

static uint16_t adc_value;
static uint16_t adc_len = sizeof( adc_value);

.... // get the value into the adc_value handle in any way you like

hvx_params.handle = p_nus->rx_handles.value_handle;
hvx_params.p_data = (uint8_t*)&adc_value;
hvx_params.p_len  = &adc_len;
hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;

return sd_ble_gatts_hvx(p_nus->conn_handle, &hvx_params);

is all in the ADC_IRQHandler() ? and we don't need to worry about the ble_nus_send_string command?

[RK]

either way - put the code in the ble_nus_send_string function (although it's no-longer NUS and no-longer sending a string so .. not really named correctly) or put it right in the ADC handler, it doesn't matter either way. I'd have a function called send_adc_data( uint16_t adc_data ) which would do it just for clean code but it doesn't really matter.

The whole point is you put the value in a static uint16_t somewhere, and you put the length of the uint16_t (which is 2) in another uint16_t somewhere and you set the p_data of the hvx_params to a pointer to the uint16_t, properly cast as a byte-pointer, and a pointer to the length in the p_len and the softdevice will then send 2 bytes starting at the first byte of the reading.

[FormerMember]

RK, I really appreciated your kindly help. I decied to place the code only inside of the "ADC_IRQHandler" for now. Could you please help me check it?

/* Interrupt handler for ADC data ready event */
void ADC_IRQHandler(void)
{
   static uint16_t adc_result;
   static uint16_t adc_len = sizeof( adc_result);

    /* Clear dataready event */
  NRF_ADC->EVENTS_END = 0;  

  /* Write ADC result both to the UART and over BLE */
    adc_result = NRF_ADC->RESULT;

            ble_gatts_hvx_params_t hvx_params;

            memset(&hvx_params, 0, sizeof(hvx_params));

            hvx_params.p_data = (uint8_t*)&adc_result;
	        hvx_params.p_len  = &adc_len;
            hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;



    //Use the STOP task to save current. Workaround for PAN_028 rev1.5 anomaly 1.
  NRF_ADC->TASKS_STOP = 1;

    //Release the external crystal
    sd_clock_hfclk_release();
}