How to dynamically change the connection interval

[Kc Owen]

Why do I use this function bt_conn_le_param_update( ), only after the power on the first time to work, then do not work

[Einar Thorsrud]

Hi,

There should not be any limitations on how often you can call bt_conn_le_param_update(), and updating the connection parameters several times during a connection is common. In what way does it not work?

[Kc Owen]

Is there no requirement for the interval between the first call to bt_conn_le_param_update() and the second call？

[Einar Thorsrud]

No. This is static. But note that this only delays connection parameter update after connection establishment. It doe snot delay subsequent connection parameter updates.

One other thing, is CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS enabled? If so, it will automatically appen after the configured delay after the connection is established.

[yuxuan.cai]

Sorry for chiming in. Are you using LLPM your application? In other words, are you using a connection interval less than 7.5ms in the first connection update call? If so, keep in mind that LLPM is only supported on 2M PHY. See https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/samples/bluetooth/llpm/README.html for more details

[Kc Owen]

Thank you for your reply. LLPM was not enabled, and the connection interval was set at 30ms. I feel that the two calls to update connection parameters were too short, resulting in the failure of the first call

[Kc Owen]

CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS is not enabled because I need to manually update the connection parameters

[yuxuan.cai]

That is odd, because it is the only condition that SDC_HCI_OPCODE_CMD_LE_CONN_UPDATE would return error code 0x0C. Could you confirm you are using Softdevice Controller? You could check if  CONFIG_BT_LL_SOFTDEVICE is set to y

[Kc Owen]

My conf file does not use CONFIG_BT_LL_SOFTDEVICE=y because my program is modified based on routines from the nRF connect SDK

[Einar Thorsrud]

Hi,

You need to check the generated .config file in your build folder to see what you actually use, as there his a hiarachy of configs, and they also have default values. If you are building for a nRF devices, you will have CONFIG_BT_LL_SOFTDEVICE=y by default unless you explicitly picked the Zephyr LL instead.