error code 13313 (0x3401) returned by ble_nus_string_send ?

[alex kim]

Hi, Everyone

I am developing based on ble_app_uart at nrf52832 (softdevice s132)

I modified the program slightly.

- After the connection is confirmed

- Send 100 bytes of data to Phone every 150ms

- Suspend transmission if connection is lost

#define NRF_BLE_GATT_MAX_MTU_SIZE 103

void gatt_init(void)
{
    ......
    err_code = nrf_ble_gatt_att_mtu_periph_set(&m_gatt, NRF_BLE_GATT_MAX_MTU_SIZE);

   ......

}

static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    uint32_t err_code;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_CONNECTED:

        ........
       app_timer_start(send_some_uart_data, APP_TIMER_TICKS(150), NULL);
       break;

       case BLE_GAP_EVT_DISCONNECTED:
               .........
              m_conn_handle = BLE_CONN_HANDLE_INVALID;
             err_code = app_timer_stop(send_some_uart_data) ;
            break;

       ..........

}

void send_some_uart_data_handler(void * p_context)
{
    ret_code_t err_code;
    uint8_t string[] = "aaaaaaaaaabbbbbbbbbbccccccccccddddddddddeeeeeeeeeeffffffffffgggggggggghhhhhhhhhhiiiiiiiiiiiiijjjjjjjjjj\n\r";
    uint16_t length = sizeof(string);
    do
    {
         err_code = ble_nus_string_send(&m_nus, string, &length);
        if ( (err_code != NRF_ERROR_INVALID_STATE) && (err_code != NRF_ERROR_BUSY) )
        {
            APP_ERROR_CHECK(err_code); <- err_code :13313 
         }
     } while (err_code == NRF_ERROR_BUSY);

}

The first time i connect to the Bluetooth on my phone, the nRFToolBox-> UART is good for receiving.
However, if i attempt to reconnect after disconnecting, 13313 err_code will occur at ble_nus_string_send(&m_nus, string, &length);

[FormerMember]

By default, the maximum length of a notification packet is 20 bytes. For "enabling" increased MTU size, there has to be an MTU exachange, where both devices agree on the new length.

In your case, what is the result from the MTU exchange between the nRF52 and the phone?

[alex kim]

Thank you for your quick response.
Please refer to the attached file below.

[FormerMember]

Could you double check the value of "length" that is being passed to ble_nus_string_send?

I would think the correct length should be the following:

uint16_t length = sizeof(string)/sizeof(uint8_t);

 

[alex kim]

Thanks for your answer.
I have attached a debug message.
I modified the code as advised, but the same thing.
Please advise.

[FormerMember]

Which error code does ble_nus_string_send() return?

Could you double check the value of all the parameters that are passed into ble_nus_string_send() at runtime? (debug mode) Could you also write their value here?