sending a char using ble_nus_data_send

[nikola]

Hi ,
I want to send a char data through bleutouth using ble nus 
I am using this method 

void sendble(char data)
{
uint8_t x = atoi(data);
uint16_t length1 ;
length1=strlen(data);
 ret_code_t ret1 = ble_nus_data_send(&m_nus,
                x,
                &length1,
                m_conn_handle);
  if (ret1 == NRF_SUCCESS) {
    NRF_LOG_RAW_INFO(" send ble success  %s",x);
  }
}

I don't have any error but I don't receive any information on my android application (NRF Toolbox).

Is there somthing wrong or I must use another command to send char value  using ble_nus send?

[Karl Ylvisaker]

Hello,

I don't have any error

You are only ever checking if your call to ble_nus_data_send is returning successfully - you will not be informed in the case that the call fails. Please pass the returned error code to an APP_ERROR_CHECK, and make sure to have DEBUG defined in your preprocessor defines, like shown in the included image:

This will make the logger output a detailed error message whenever a non-NRF_SUCCESS error code is passed to an APP_ERROR_CHECK.

Furthermore, the second argument of the ble_nus_data_send call should be a uint8_t pointer, not a uint8_t value, please change rectify this.

Best regards,
Karl

[nikola]

I have got this error 

[Karl Ylvisaker]

The complete error message is not visible. Please do not share error logs as screenshots for this reason.

The error code was NRF_ERROR_NOT_FOUND. If you look at the end of the error report it will tell you which line it was triggered. Find out which function returned this error code, and check the API reference of the function to see why it would return NRF_ERROR_NOT_FOUND, to find out how you can fix it.

Best regards,
Karl

[nikola]

the error was on the ble_nus_data_send function 
How can I check the API reference of the function ?

[nikola]

this is what the ble_nus_data_send return 

 ret = ble_nus_data_send(&m_nus,
                (uint8_t *)m_cdc_data_array,
                &length,
                m_conn_handle);

            if (ret == NRF_ERROR_NOT_FOUND) {
              NRF_LOG_INFO("BLE NUS unavailable, data received: %s", m_cdc_data_array);
              break;
            }

            if (ret == NRF_ERROR_RESOURCES) {
              NRF_LOG_ERROR("BLE NUS Too many notifications queued.");
              break;
            }

            if ((ret != NRF_ERROR_INVALID_STATE) && (ret != NRF_ERROR_BUSY)) {
              APP_ERROR_CHECK(ret);
            }
          } while (ret == NRF_ERROR_BUSY);
        }

        index = 0;
      }

[Karl Ylvisaker]

nikola said:

How can I check the API reference of the function ?

You can find the API reference of all SDK functions on the Infocenter. In this particular case, you can find the ble_nus_data_send function's API reference here.
If the API reference does not specify the specific error code you are seeing, you must go into the function's source code to see what other error codes it might return, or what other functions it calls within that might return this error code.
You can set breakpoints in the source code of the function too, to pinpoint exactly where the error is generated.

Best regards,
Karl

[Karl Ylvisaker]

nikola said:

this is what the ble_nus_data_send return 

This is only the handling for some of the code that it might return. You are not guaranteed that this covers all codes that it might return.
To see the full picture, you should look into the source code of the ble_nus_data_send function, to see all the error codes it might return.

Best regards,
Karl

[nikola]

this is what the function return :

uint32_t ble_nus_data_send(ble_nus_t * p_nus,
                           uint8_t   * p_data,
                           uint16_t  * p_length,
                           uint16_t    conn_handle)
{
    ret_code_t                 err_code;
    ble_gatts_hvx_params_t     hvx_params;
    ble_nus_client_context_t * p_client;

    VERIFY_PARAM_NOT_NULL(p_nus);

    err_code = blcm_link_ctx_get(p_nus->p_link_ctx_storage, conn_handle, (void *) &p_client);
    VERIFY_SUCCESS(err_code);

    if ((conn_handle == BLE_CONN_HANDLE_INVALID) || (p_client == NULL))
    {
        return NRF_ERROR_NOT_FOUND;
    }

    if (!p_client->is_notification_enabled)
    {
        return NRF_ERROR_INVALID_STATE;
    }

    if (*p_length > BLE_NUS_MAX_DATA_LEN)
    {
        return NRF_ERROR_INVALID_PARAM;
    }

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

    hvx_params.handle = p_nus->tx_handles.value_handle;
    hvx_params.p_data = p_data;
    hvx_params.p_len  = p_length;
    hvx_params.type   = BLE_GATT_HVX_NOTIFICATION;

    return sd_ble_gatts_hvx(conn_handle, &hvx_params);
}

[Karl Ylvisaker]

nikola said:

this is what the function return :

This is the source code of the function, yes.
At the bottom, it returns the NRF_ERROR_NOT_FOUND error code, returned from the call to sd_ble_gatts_hvx. Please check this function's API Reference to see why it returned this error code.

Best regards,
Karl