Connection Interval update issue

RE: Connection Interval update issue

masterLee — Tue, 09 Nov 2021 11:31:42 GMT

Ok I found this posti explaining it
devzone.nordicsemi.com/.../difference-between-ble-parameter-update-functions

RE: Connection Interval update issue

masterLee — Tue, 09 Nov 2021 11:10:57 GMT

ok. It worked. One last question regarding the update

What is the difference of sd_ble_gap_conn_param_update() and ble_conn_params_change_conn_params()

Thank you for your time

RE: Connection Interval update issue

Edvin — Mon, 08 Nov 2021 15:10:15 GMT

You have to look for the BLE_GAP_EVT_CONN_PARAM_UPDATE events on the peripheral.

RE: Connection Interval update issue

masterLee — Mon, 08 Nov 2021 09:42:44 GMT

Hi, is there some way to check if the connection interval request from the peripheral to the mobile is accepted or not? Like a flag or something?

RE: Connection Interval update issue

masterLee — Fri, 05 Nov 2021 14:46:48 GMT

It seems that I will need an adapter between the windows application and the peripheral devices where I can modify the connection Interval the way I want. Maybe an nRF52840 as central would be the solution here

RE: Connection Interval update issue

Edvin — Fri, 05 Nov 2021 14:20:16 GMT

If the central is a mobile phone or a computer, it may not be that easy to actually change the connection interval. Although I am not exactly sure how it is set on computers. It may be adjustable in some app for peripherals with custom BLE Services, but I think that with e.g. HID over BLE, the computer want to keep the connection interval low, to reduce latency. In this case slave_latency can be applied in order to reduce current consumption. Perhaps you can look into that.

Best regards,

Edvin

RE: Connection Interval update issue

masterLee — Fri, 05 Nov 2021 13:17:26 GMT

Hi,

The application that wrote the logs comes from the peripheral device (nRF52840) debugger.

The central is not nRF device. It is a custom windows 10 desktop application with an external BLE 5.0 usb adapter.

I have already contacted the app developer and he is trying to find the configuration for the connection parameters.

RE: Connection Interval update issue

Edvin — Fri, 05 Nov 2021 13:08:00 GMT

The application that wrote these logs, is that a peripheral or a central?

It is always the central that has the final saying on the connection parameters. I guess that this is the peripheral. Are you developing the central as well? Or do you have access to the central source code? What is the preferred connection parameters on the central? I suspect it is maximum 12. If the central is another nRF, can you try to change the preferred connection interval to something else?

BR,
Edvin

RE: Connection Interval update issue

masterLee — Fri, 05 Nov 2021 10:20:48 GMT

Hi Edvin,

Good news and bad news. The good news are that the values now make

Bad news are that, after the first update event with the agreed connection interval value (30) which is inside the min max limits I have set , a second update event takes place automatically with another value (12) outside the defined limits, as displayed next

<info> app: BLE GAP Connected
<info> app: Conn.Interval is initialized. Max: 0x24, Min: 0x24, Max: 36, Min: 36
<info> app: Data len is set to 0xF4(244)
<info> app: Data len is set to 0xF4(244)
<info> app: Request Bytes = 5
<info> app: Conn.Interval in function. Max: 0x20, Min: 0x18, Max: 32, Min: 24
<info> app: Conn.Interval is updated. Max: 0x1E, Min: 0x1E, Max: 30, Min: 30
<info> app: Conn.Interval is updated. Max: 0xC, Min: 0xC, Max: 12, Min: 12

How is it possible a second connection interval update event to take place and change the value by its own?

By repeating the process with different min max values for the connection interval, the first update event takes the values correctly and the agreed value is within the set limits and the second update that occurs automatically returns the set value back to 12.

RE: Connection Interval update issue

masterLee — Thu, 04 Nov 2021 17:45:50 GMT

Hi Edvin, I will try it out first thing tomorrow morning and I will come back.
Thank you for your time!

RE: Connection Interval update issue

Edvin — Thu, 04 Nov 2021 14:22:44 GMT

Hello,

In your last snippet (before the log snippet), you use the parameters from the connected event, while the event type is actually BLE_GAP_EVT_CONN_PARAM_UPDATE, so they will not be correctly populated.

Try replacing:

case BLE_GAP_EVT_CONN_PARAM_UPDATE:
            if(userRequest == UR_CONNINUPDT)
            {
              uint16_t max =  p_ble_evt->evt.gap_evt.params.connected.conn_params.max_conn_interval;
              uint16_t min =  p_ble_evt->evt.gap_evt.params.connected.conn_params.min_conn_interval;
              NRF_LOG_INFO("Conn.Interval is updated. Max: 0x%X, Min: 0x%X, Max: %d, Min: %d", max, min, max, min);
              conn_params_updated = true;
            }
            break;

with:

case BLE_GAP_EVT_CONN_PARAM_UPDATE:
            if(userRequest == UR_CONNINUPDT)
            {
              uint16_t max =  p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.max_conn_interval;
              uint16_t min =  p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.min_conn_interval;
              NRF_LOG_INFO("Conn.Interval is updated. Max: 0x%X, Min: 0x%X, Max: %d, Min: %d", max, min, max, min);
              conn_params_updated = true;
            }
            break;

And see if that solves it.

Best regards,

Edvin