nRF52832 connection problem with some android device

[Youngjun]

Hi, I'm using nRF52832 with sdk 13.0.0(softdevice 4.0.2). I had trouble to connect nRF52 and some android 7.0(or upper version) smart device. I tested samsung galaxy tap 10.1 A6 (android 7.0) and LG V20(android 7.0). When I connect by nRF Connect application, I got "Error (0x8) GATT CONN TIMEOUT" message. But, another smart device(nexus 5X, samsung galaxy s8)is work well. Has anyone ever happened to this?

Thanks, Regards Youngjun.

[Hung Bui]

Hi Yongjun,

When you receive "Error (0x8) GATT CONN TIMEOUT" it's right after you clicked "Connect" button ? Meaning the connection actually wasn't established ? Or that error arrived after you connect for a while ?

Which firmware did you use ? Could you try with ble_app_hrs for example ?

[Youngjun]

Hi Hung Bui. Thank you for your reply. I received error message when i pressed connect button. My log is like below.

• Connected to FF:51:1C:9B:90:68
• Error 8 (0x8): GATT CONN TIMEOUT
• Disconnected 　 I use ble_app_hrs example and sdk13.0.0 s132.

Thanks, Regards Youngjun.

[Hung Bui]

It would be useful to have a sniffer trace to see what happens over the air.

Could you check if there is any assertion on the nRF52?

Could you check in on_ble_evt() if the BLE_GAP_EVT_CONNECTED event occurred ? and then BLE_GAP_EVT_DISCONNECTED event happens after that ? If there is BLE_GAP_EVT_DISCONNECTED, which disconnected reason (check the p_ble_evt) ?

[Youngjun]

I checked that the brakepoint is working at BLE_GAP_EVT_CONNETED and BLE_GAP_EVT_DISCONNECTED. And, nRF52 connected with V20 in nRF52 debugging mode. But, a few seconds after, nRF52 disconnected automatically. the log was "Disconnected, reason 42". Thanks.Thanks, Regards Youngjun.

[Hung Bui]

Are you sure it's reason 42 = 0x2A = BLE_HCI_DIFFERENT_TRANSACTION_COLLISION ? It's a pretty strange disconnection reason, I haven't seen it before. Maybe you want to add a break point in BLE_GAP_EVT_DISCONNECTED event and check ?

You also may want to have a look at this case and this similar case.

Not sure if it's the same issue, if you can capture a sniffer trace, it would be clearer.