notifications for two characteristics is not working

[Namdev]

Hello,

I have one service and two characteristics in my example code.

I have used the Github tutorial to learn how the notification works. I followed the same for my implementation.

When i test the notification separately by commenting out the code in the notification handler it works fine. Both the characteristics notification is working properly without any problem but when i enable two notifications in two characteristics it gives out error with an error code 13313 when trying to send the values to android application.

My code snippet is attached

The above code snippet is from custom service file which has two characteristics and one service with two functions for notification.

/**@brief Function for handling the Battery measurement timer timeout.
*
* @details This function will be called each time the battery level measurement timer expires.
*
* @param[in] p_context Pointer used for passing some arbitrary information (context) from the
* app_start_timer() call to the timeout handler.
*/
static void notification_timeout_handler(TimerHandle_t xTimer)
{
UNUSED_PARAMETER(xTimer);
ret_code_t err_code;

// // Increment the value of m_custom_value before nortifing it.
m_custom_value++;
d_custom_value++;

err_code = ble_cus_custom_value_update(&m_cus, m_custom_value);
APP_ERROR_CHECK(err_code);

err_code = ble_tmp_custom_value_update(&m_cus, d_custom_value);
APP_ERROR_CHECK(err_code);
}

Here in the above code when i comment out either of the functions the notification works fine. If i keep both the update functions it shows an error code 13313.

It would be great if someone can help me solve this issue in the earliest as my project is in a critical stage.

[cbd]

I can't comment on the code within ble_custom_value_update and ble_tmp_custom_value_update and whether there is a cut and paste error i.e. duplicate code - same characteristic being indicated by each function, but you will need to either increase the indication queue size or only raise the indication for the second characteristic once the first has been handled.

From the Soft Device documentation (I've highlighted in bold the sentence that you may be operating contrary to):

Note

The local attribute value may be updated even if an outgoing packet is not sent to the peer due to an error during execution. The Attribute Table has been updated if one of the following error codes is returned: NRF_ERROR_INVALID_STATE, NRF_ERROR_BUSY, NRF_ERROR_FORBIDDEN, BLE_ERROR_GATTS_SYS_ATTR_MISSING and NRF_ERROR_RESOURCES. The caller can check whether the value has been updated by looking at the contents of *(ble_gatts_hvx_params_t::p_len). Only one indication procedure can be ongoing per connection at a time. If the application tries to indicate an attribute value while another indication procedure is ongoing, the function call will return NRF_ERROR_BUSY. A BLE_GATTS_EVT_HVC event will be issued as soon as the confirmation arrives from the peer. The number of Handle Value Notifications that can be queued is configured by ble_gatts_conn_cfg_t::hvn_tx_queue_size When the queue is full, the function call will return NRF_ERROR_RESOURCES. A BLE_GATTS_EVT_HVN_TX_COMPLETE event will be issued as soon as the transmission of the notification is complete. The application can keep track of the available queue element count for notifications by following the procedure below:

• Store initial queue element count in a variable.
• Decrement the variable, which stores the currently available queue element count, by one when a call to this function returns NRF_SUCCESS.
• Increment the variable, which stores the current available queue element count, by the count variable in BLE_GATTS_EVT_HVN_TX_COMPLETE event.

[Namdev]

Thank you for your quick response. I am trying to insert code but the attachment is failing. Can you tell me if there are any other tutorials which shows how to implement notifications for two characteristics?