nRF52 automatically disconnects with iOS phone after 90 seconds

RE: nRF52 automatically disconnects with iOS phone after 90 seconds

Vidar Berg — Mon, 16 Mar 2020 07:26:12 GMT

Ok, it sounds like the FW app is disconnecting because the iPhone rejected "MAX_CONN_PARAMS_UPDATE_COUNT" number of requests. You can either change the app so it doesn't disconnect even if the requested connection parameters are rejected, or you can change your connection parameters according to the recommendations given in the Apple document I linked in my previous response.

Connection Parameters Negotiation

RE: nRF52 automatically disconnects with iOS phone after 90 seconds

RO — Fri, 13 Mar 2020 21:34:41 GMT

I added the log code and I get '0x16' , which means Local host terminated connection.

It does seem something to do with connection parameter updates.

When I change the MAX_CONN_PARAMS_UPDATE_COUNT from 3 to 2, now the disconnections happen in 60 seconds.

#define FIRST_CONN_PARAMS_UPDATE_DELAY   APP_TIMER_TICKS(5000)                      /**< Time from initiating event (connect or start of notification) to first time sd_ble_gap_conn_param_update is called (5 seconds). */
#define NEXT_CONN_PARAMS_UPDATE_DELAY    APP_TIMER_TICKS(30000)                     /**< Time between each call to sd_ble_gap_conn_param_update after the first call (30 seconds). */
#define MAX_CONN_PARAMS_UPDATE_COUNT     2

So what is the solution?

Thanks

RE: nRF52 automatically disconnects with iOS phone after 90 seconds

Vidar Berg — Fri, 13 Mar 2020 12:47:05 GMT

I agree with jacksong, a good first step is to figure out what the disconnect reason is. You can also check the callback from the connection parameter module (registered through ble_conn_params_init() to see if the connection param update requests are being rejected. Also, note that SDK 14.2.0 should not be used with 52840 because we had limited support for it in this release. It's important that you migrate to SDK v15 or preferably v16 before going to production.

Apple recommandations:

https://developer.apple.com/accessories/Accessory-Design-Guidelines.pdf

RE: nRF52 automatically disconnects with iOS phone after 90 seconds

jacksong — Fri, 13 Mar 2020 02:05:15 GMT

sounds like it is update connection parameter fail, you need to check the reason code of disconnect.

you can add log code at on_ble_evt() , and then check the meaning of reason at "ble_hci.h" at line 56.

on_ble_evt((ble_evt_t * p_ble_evt))
{
...
    case BLE_GAP_EVT_DISCONNECTED:
    {
        ...
    
        NRF_LOG_RAW_INFO("disconnect reason:0x%X",p_ble_evt->evt.gap_evt.params.disconnected.reason);

        ...
    }
    break;

...

}