NUS central example can't send more than 4 packets of 244 Bytes

[TermiteUser]

Hi everybody,

I have some trouble fixing the ERROR 19 [NRF_ERROR_RESOURCES]. I think it's something about the buffer queue size that is too busy. But I don't know how to fix it because most of the resolution on that matter was on the peripheral side with BLE_GATTS_EVT_HVN_TX_COMPLETE but it's a server whereas on the central side it's a client. 

So I think I can't solve my problem with BLE_GATTS_EVT_HVN_TX_COMPLETE or I misunderstood something.

If you could enlighten me on that matter or give me some solutions. It would be great.

Some informations that might be useful : 

NRF_SDH_BLE_GAP_EVENT_LENGTH is 320

NRF_SDH_BLE_GAP_DATA_LENGTH is 251

NRF_SDH_BLE_GATTS_ATTR_TAB_SIZE 1408

// Where I send my 244 Bytes data

void uart_event_handle(app_uart_evt_t * p_event)
{
    static uint8_t data_array[BLE_NUS_MAX_DATA_LEN];
    
    static uint16_t index = 0;
	static uint32_t ret_val;
    static uint16_t length = 244;
	static uint8_t j;
	static uint8_t send_data[BLE_NUS_MAX_DATA_LEN];
  
    
	for (uint8_t i=0; i<length; i++)
	{
		send_data[i]=i;
	}
    switch (p_event->evt_type)
    {
        /**@snippet [Handling data from UART] */
        case APP_UART_DATA_READY:
            UNUSED_VARIABLE(app_uart_get(&data_array[index]));
            index++;

            if (//(data_array[index - 1] == '\n') ||
                (data_array[index - 1] == '\r') ||
                (index >= (m_ble_nus_max_data_len)))
            {
                NRF_LOG_INFO("Ready to send data over BLE NUS");
                NRF_LOG_HEXDUMP_INFO(data_array, index);

                do
                {
					if (index % 4 != 0 || index > 4)
                    {
						for (int i=0;i<10;i++)
						{
								ret_val = ble_nus_c_string_send(&m_ble_nus_c, send_data, length);
						}
					}

                    if ( (ret_val != NRF_ERROR_INVALID_STATE) && (ret_val != NRF_ERROR_RESOURCES) &&
						(ret_val != NRF_ERROR_NOT_FOUND))
                    {
                        APP_ERROR_CHECK(ret_val);
                    }
                } while (ret_val == NRF_ERROR_RESOURCES);

                index = 0;
            }
            break;

        /**@snippet [Handling data from UART] */
        case APP_UART_COMMUNICATION_ERROR:
            NRF_LOG_ERROR("Communication error occurred while handling UART.");
            APP_ERROR_HANDLER(p_event->data.error_communication);
            break;

        case APP_UART_FIFO_ERROR:
            NRF_LOG_ERROR("Error occurred in FIFO module used by UART.");
            APP_ERROR_HANDLER(p_event->data.error_code);
            break;

        default:
            break;
    }
}

Best Regards,

[Edvin]

Not possible. You could handle the SPI inside the interrupt by calling a function from the interrupt. But if you spend too long time, you risk loosing future BLE events. 

I suggest you try to double buffer the m_buffer_tx[]. Even though you get two events quite quickly, there is a lot of time between the connection events to handle your data. Alternatively you can look into something called a ring buffer.

BR,

Edvin

[TermiteUser]

I see I will try to implement your solution then. Thanks for that.

That's one problem that has been solved. Unfortunately I still have my initial my problem which involve BLE_GATTC_EVT_WRITE_CMD_TX_COMPLETE.

I tested it and I did trigger the event but i was wondering if that it's normal that It triggers after I send all my packets instead of triggering after one packet. 

That's my logs : 

<info> app: packet sent
<info> app: packet sent
<info> app: packet sent
<info> app: packet sent
<info> app: Buffer empty
<info> app: Buffer empty
<info> app: Buffer empty
<info> app: Buffer empty

For information the version of my SDK is nRF5_SDK_17.0.2_d674dde
And I put the event in the void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)

[TermiteUser]

Hi Edwin,

I was wondering if you has an update on my problem ? 

Br,

[TermiteUser]

Hi, 

Still no update... ?

Best regards,

[TermiteUser]

For people that may need the answer I got it here : https://devzone.nordicsemi.com/f/nordic-q-a/69412/how-ble_gattc_evt_write_cmd_tx_complete-event-works