Error: (0x22): GATT CONN LMP TIMEOUT

[xiang san]

Hi,

Every 40 seconds after successful connection，the  connection lost, The interval is very fixed. What's the reason？

thanks!

[Edvin]

Hello,

Are you using the nRF5 SDK or NCS for your nRF Application?

40 seconds sounds like something is timing out. I suspect it is the peripheral not being satisfied with the connection parameters (mainly the connection interval). Does the log on the nRF say anything when disconnecting?

If you are using the nRF5 SDK, look in your nRF application for something like this:

    cp_init.disconnect_on_fail             = true;

used in combination with ble_conn_params_init().

The disconnect_on_fail parameter is used to decide whether the peripheral will disconnect if it doesn't get the connection interval between min_conn_interval and max_conn_interval, after three attempts. 

If the disconnect_on_fail is already set to false, can you please capture a sniffer trace of the connection, in addition to attaching the log from the nRF52840? Perhaps there is some other request that the nRF does not respond to properly.

Best regards,

Edvin

[xiang san]

I found that this problem is related to the mobile phone brand. Huawei mobile phones do not have this problem, while Xiaomi mobile phones have this problem. If I guess correctly, it is related to the adjustment of Bluetooth parameters in the mobile phone system.

Thanks!