NUS handler for ADC

[mars_design]

I'm trying to use the NUS to send data over from NRF52 dev kit to the NRF Connect app. Using Putty for UART works fine. Now I adapted to read out ADC values from 2 ADC ports, but data is unreadable on phone application.

Found lots of other code on the internet and adapted the best, but now stuck at this problem.

 See below part code:


        ret_code_t err_code;
        uint16_t adc_value;
        uint8_t value[SAADC_SAMPLES_IN_BUFFER*2];
        uint8_t bytes_to_send;
     
        // set buffers
        err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, SAADC_SAMPLES_IN_BUFFER);
        APP_ERROR_CHECK(err_code);
						
        // print samples on hardware UART and parse data for BLE transmission
        printf("ADC event number: %d\r\n",(int)m_adc_evt_counter);
        for (int i = 0; i  data.done.p_buffer[i]);

            adc_value = p_event->data.done.p_buffer[i];
            value[i*2] = adc_value;
            value[(i*2)+1] = adc_value >> 8;
        }
				
        // Send data over BLE via NUS service. Makes sure not to send more than 20 bytes.
        if((SAADC_SAMPLES_IN_BUFFER*2) <= 20) 
        {
            bytes_to_send = (SAADC_SAMPLES_IN_BUFFER*2);
        }
        else 
        {
            bytes_to_send = 20;
        }
        err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);
        if (err_code != NRF_ERROR_INVALID_STATE) 
        {
            APP_ERROR_CHECK(err_code);
        }
						
        m_adc_evt_counter++;
    }

[awneil]

err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);

This just sends the contents the value[] array as raw binary data - is that what you intended?

[mars_design]

Actually I adapted this line:

err_code = ble_nus_string_send(&m_nus, value, bytes_to_send);

Since this is the example code from the internet, which gives a lot of errors with SDK15, therefore I changed a lot myself.  (https://github.com/NordicPlayground/nRF52-ADC-examples/tree/master/ble_app_uart__saadc_timer_driven__scan_mode )

This is what I have now.

ble_nus_data_send(&m_nus, value, &bytes_to_send, m_conn_handle);

[awneil]

But that will also just send the contents the value[] array as raw binary data.

Again:  is that what you intended?

[mars_design]

No. I'd like to have no raw binary data. I'd like to have readable data, same as when sending "hello123" via putty, that it shows "hello123"

[awneil]

OK. So this is standard 'C' stuff - nothing specifically to do with Nordic or micrococontrollers.

Just like you did here to convert the data into printable text:

printf( "ADC event number: %d\r\n", (int)m_adc_evt_counter );

You need to use sprintf() or suchlike to convert the data into printable format, and then send that.

http://www.cplusplus.com/reference/cstdio/sprintf/