Is there any relation between connection parameters and occasionally disconnection

RE: Is there any relation between connection parameters and occasionally disconnection

Petter Myhre — Mon, 02 Oct 2017 11:59:42 GMT

Ok. If you get BLE_HCI_CONNECTION_TIMEOUT on the nRF peripheral, it is either not able to receive packets from the central, or the central isn't sending out packets, and the it hits he supervision timeout. Have you tested the nRF peripheral with another central? For example nRF Connect on Android? Does it disconnect then? If not I would suspect that the issue is with the central device. This could be confirmed with doing a sniffer trace, to see what is actually happening on air.

RE: Is there any relation between connection parameters and occasionally disconnection

Sansei — Mon, 02 Oct 2017 11:45:53 GMT

Yes, as I said previously in question I get timeout error (0x8) exactly on BLE_GAP_EVT_DISCONNECTED event. No, it doesn't reset and there is no error somewhere really.

RE: Is there any relation between connection parameters and occasionally disconnection

Petter Myhre — Mon, 02 Oct 2017 10:14:05 GMT

Then it is probably not the connection parameters that is the culprit. Do you get a BLE_GAP_EVT_DISCONNECTED event? Have you checked the disconnect reason? Have you checked that APP_ERROR_CHECK() isn't called with an error somewhere? And the device resets?

RE: Is there any relation between connection parameters and occasionally disconnection

Sansei — Mon, 02 Oct 2017 09:38:12 GMT

Thanks again. Actually, regardless of setting any value for CST (6S - 20S) when I set Connection Interval >= 600 ms I will get disconnection event in about 5 minutes after establishing the connection. Having a stable connection is very critical for us. At the second step, we also have to save the Battery as far as possible.

RE: Is there any relation between connection parameters and occasionally disconnection

Petter Myhre — Mon, 02 Oct 2017 07:46:01 GMT

Ok. So it seems the peripheral is sending a connection parameter update request, and the central is accepting it, sends a connection parameter update, and the connection parameters are updated.

If you think the connection parameters are the reason for why you get a disconnect (I'm not sure why you think this?) just change the parameters that you include in the connection parameter update request from the peripheral. Or don't send a CPU request at all, then you will just keep the connection parameters used when connecting (CM = 100 ms, SL = 0, CST = 20 S).

RE: Is there any relation between connection parameters and occasionally disconnection

Sansei — Fri, 29 Sep 2017 17:25:18 GMT

Yes, I think I know them. These are what I set on peripheral: Minimum Connection interval = 500 ms; Maximum Connection interval = 1000 ms; Slave Latency = 0; Connection supervision timeout = 6 S

Values I received on BLE_GAP_EVT_CONNECTED event: Minimum Connection interval = 100 ms; Maximum Connection interval = 100 ms; Slave Latency = 0; Connection supervision timeout = 20 S;

Values I received on BLE_GAP_EVT_CONN_PARAM_UPDATE event: Minimum Connection interval = 500 ms; Maximum Connection interval = 500 ms; Slave Latency = 0; Connection supervision timeout = 6 S;

Crashing our system because of abnormal disconnection is fatal. Currently, timeout is the reason of crashing our system, on both client and peripheral, while they are really in the response range and are close to each other.

RE: Is there any relation between connection parameters and occasionally disconnection

Petter Myhre — Fri, 29 Sep 2017 11:57:15 GMT

You need to find a balance between the connection interval and the supervision timeout. There is no best values, you have to tune them to your use case. What kind of connection interval are you using? What have you set supervision timeout to? Do you know the meaning of these?

RE: Is there any relation between connection parameters and occasionally disconnection

Sansei — Fri, 29 Sep 2017 11:14:32 GMT

Thanks for your response... I will check parameters as the way you mentioned. But please let me know what are best values to avoid occasionally disconnection problem while I need to get the feedback of true disconnection (when really I get out from the response range by leaving the place/room) as much as fast.

RE: Is there any relation between connection parameters and occasionally disconnection

Petter Myhre — Fri, 29 Sep 2017 08:58:58 GMT

It is the central device that dictates the connection parameters (when connection is established), it can then choose to do a connection parameter update to change them.

What are your actual connection parameters? See this for how to check. What are the connection parameters when you get the BLE_GAP_EVT_CONNECTED event? Do you get any BLE_GAP_EVT_CONN_PARAM_UPDATE events? What are the connection parameters then?