Central and Peripheral disconnect error!

RE: Central and Peripheral disconnect error!

Einar Thorsrud — Mon, 02 Nov 2020 14:18:55 GMT

Hi,

You will get BLE_HCI_CONNECTION_TIMEOUT if there is a supervision timeout. However, if there was never any packets successfully transferred after the connection request, the timeout is shorter, and the reason will be BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED. This post describes it well. More details form the BT spec (4.2):

The Connection Failed to be Established error code indicates that the LL
initiated a connection but the connection has failed to be established.

If you only see this when doing a lot of(?) flash operations, it could be that the SoftDevices schedules flash writes so that ble events are missed.

RE: Central and Peripheral disconnect error!

srac — Mon, 02 Nov 2020 08:28:55 GMT

Thank you

RE: Central and Peripheral disconnect error!

srac — Mon, 02 Nov 2020 08:24:40 GMT

[quote userid="7377" url="~/f/nordic-q-a/67839/central-and-peripheral-disconnect-error/277873#277873"]This is not clear to me. Can you clarify if the nRF acts as a central or peripheral when this error occurs?[/quote]

Both devices are nrf52832. I am doing some flash operations and changing advertising data after the connection after the disconnection. When i am doing with nrf uart app Peripheral is making all flash operations and other processes but if i use the central nrf52832 i am transfering data perfectly after i call

 uint8_t err_code = sd_ble_gap_disconnect(m_ble_nus_c.conn_handle,
                        BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION);

Then Peripheral does not changing the advertising data and pheripheral's disconnection reason is 0x3E BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED (in uart app disconnection reason is 0x13 which is BLE_HCI_REMOTE_USER_TERMINATED_CONNECTION).

On the otherhand if I dont use sd_ble_gap_disconnect and somehow manage to timeout the connection, then pheripheral gets 0x08 BLE_HCI_CONNECTION_TIMEOUT as a disconnect reason and pheripheral doing all flash operations and changing advertising data.

RE: Central and Peripheral disconnect error!

Einar Thorsrud — Fri, 30 Oct 2020 15:42:32 GMT

Hi,

[quote user=""]ıt works fluently on the central side. But at the Peripheral side disconnection reason become[/quote]

This is not clear to me. Can you clarify if the nRF acts as a central or peripheral when this error occurs?

If the nRF acts as a central that connects to a peripheral, then you would typically get this reason if the peripheral ignores the connection request, for instance if it uses a whitelist and the initiator is not in the whitelist.

There could also be other problems you could see in either role, where no packets are exchanged after the connection request due to some other error (clock drift, interference, etc.)

RE: Central and Peripheral disconnect error!

awneil — Fri, 30 Oct 2020 14:44:28 GMT

Usually a "beacon" is taken to mean something that just advertises - it does not connect.