S110 Disconnects when in connection with S120

RE: S110 Disconnects when in connection with S120

Andy — Tue, 15 Mar 2016 18:53:20 GMT

Based on Pal's response, this GAP Message Sequence Chart is incorrrect. The S110 peripheral cannot handle variant #3, where the Central ignore's the request. Instead of a timeout and BLE_GAP_EVT_CONN_PARAM_UPDATE event, the connection is dropped (BLE_HCI_LOCAL_HOST_TERMINATED_CONNECTION).

RE: S110 Disconnects when in connection with S120

Pål Håland — Tue, 13 May 2014 12:35:39 GMT

Hi, this disconnection a stack handled timer that disconnect the connection because no response have been given on the L2CAP Connection Parameter Update Request. This timer is at 30 seconds, and if no response is given within that timeframe from the central device. Then the stack initiates the disconnection. This is the reason why I said that the app on the s120 device had to handle the BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST.

RE: S110 Disconnects when in connection with S120

Phil Beeson — Tue, 13 May 2014 12:10:04 GMT

Hi Pål ,

Thanks for your response. You seem to be right about it being related to connection parameter renegotiation, if I change my min & max connection parameters on the peripheral to be within the range initially established when the S120 connects then the link stays active.

Can you explain this further though. Is this timeout in the soft device itself? In the peripheral code (which is based on the HRS example) the connection parameter's disconnect_on_fail parameter is set false, and I have confirmed with the debugger that neither of the calls to sd_ble_gap_disconnect() [in update_timeout_handler/ble_conn_params.c or on_conn_params_evt/main.c] are being called.

Thanks for again for your help and insight.

Phil.


static void conn_params_init(void)
{
    uint32_t               err_code;
    ble_conn_params_init_t cp_init;

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

    cp_init.p_conn_params                  = NULL;
    cp_init.first_conn_params_update_delay = FIRST_CONN_PARAMS_UPDATE_DELAY;
    cp_init.next_conn_params_update_delay  = NEXT_CONN_PARAMS_UPDATE_DELAY;
    cp_init.max_conn_params_update_count   = MAX_CONN_PARAMS_UPDATE_COUNT;
    cp_init.start_on_notify_cccd_handle    = BLE_GATT_HANDLE_INVALID;
    **cp_init.disconnect_on_fail             = false;**
    cp_init.evt_handler                    = on_conn_params_evt;
    cp_init.error_handler                  = conn_params_error_handler;

    err_code = ble_conn_params_init(&cp_init);
    APP_ERROR_CHECK(err_code);
}

RE: S110 Disconnects when in connection with S120

Pål Håland — Tue, 13 May 2014 10:19:27 GMT

You can remove the .txt and open it in wireshark

RE: S110 Disconnects when in connection with S120

Wojtek — Tue, 13 May 2014 10:18:39 GMT

I don't have software to analyze this packet at the moment, but what is exact specification of Your service? Does it only use notification?

RE: S110 Disconnects when in connection with S120

Pål Håland — Tue, 13 May 2014 10:18:14 GMT

Hi,

at packet 674 I see that the peripheral send some data on L2CAP (Looks like garbled data) and 30 seconds after that a timer triggers, causing the disconnection.

Do the peripheral do a Connection Parameter Update Request? In that case the central should handle the event BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST, and issue a sd_ble_gap_conn_param_update. (To respond to the request)

BR Pål