nRF52840 not advertising after disconnect

RE: nRF52840 not advertising after disconnect

Kenneth — Thu, 28 May 2020 09:13:22 GMT

You are executing an sd_ble_gatts_*() procedure at some time, and there is no response from the peer, causing an:
https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.s140.api.v7.0.1/group___b_l_e___g_a_t_t_s___t_i_m_e_o_u_t___m_s_c.html

If you are able to find which sd_ble_gatts_*() that is called and not responded that would help. Maybe an on-air sniffer log can be done.

RE: nRF52840 not advertising after disconnect

akaun — Tue, 26 May 2020 14:45:35 GMT

It looks like GATT_Server_Timeout why the error happens.

case BLE_GATTS_EVT_TIMEOUT:
            // Disconnect on GATT Server timeout event.
            NRF_LOG_DEBUG("GATT Server Timeout.");
            err_code = sd_ble_gap_disconnect(p_ble_evt->evt.gatts_evt.conn_handle,
                                             BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);
            APP_ERROR_CHECK(err_code);
            break;

RE: nRF52840 not advertising after disconnect

akaun — Tue, 26 May 2020 14:17:52 GMT

Ok so I added app_error_check to timers, seems to be ok there. My ADV_EVT_IDLE does tell the device to go to sleep, but adding start_advertise did't do anything. If I try to add start_advertising inside disconnect I get error, see picture attached.

static void ble_evt_handler(ble_evt_t const * p_ble_evt, void * p_context)
{
    ret_code_t err_code = NRF_SUCCESS;

    switch (p_ble_evt->header.evt_id)
    {
        case BLE_GAP_EVT_DISCONNECTED:
            NRF_LOG_INFO("Disconnected.");
            m_conn_handle = BLE_CONN_HANDLE_INVALID;

            ret_code_t err_code = ble_advertising_start(&m_advertising, BLE_ADV_MODE_FAST);
            APP_ERROR_CHECK(err_code);

            //Work around for device not advertising
            //NVIC_SystemReset();
            //*******^

            // LED indication will be changed when advertising starts.
            break;

RE: nRF52840 not advertising after disconnect

Kenneth — Tue, 26 May 2020 11:54:44 GMT

You should add error check of app_timer_start() and app_timer_stop(), to check if there is any error.

Also you can typically on BLE_GAP_EVT_DISCONNECTED event add that you want to start advertisement again.

You may also look into what your application is setup to do on BLE_ADV_EVT_IDLE event if you are using the advertisement module. For instance do you want to go to sleep or start advertisement again?