peripherials fail to connect to central (nrf5340) if another central (nrf5340) is scanning nearby

RE: peripherials fail to connect to central (nrf5340) if another central (nrf5340) is scanning nearby

Vidar Berg — Mon, 24 Feb 2025 08:26:55 GMT

If it keeps failing, then I think it would make sense to verify whether the peripheral is still doing connectable advertisements at that time. You can use a BLE sniffer or check the peripheral's debug logs for this.

RE: peripherials fail to connect to central (nrf5340) if another central (nrf5340) is scanning nearby

Aravibala — Sun, 23 Feb 2025 06:07:27 GMT

hi,

thank you for the mail sorry for the delay, if you see in the debugging log you can notice that we are trying to connection again by enabling the filters and the device also gets discivered but it fails to connect.

RE: peripherials fail to connect to central (nrf5340) if another central (nrf5340) is scanning nearby

Vidar Berg — Thu, 20 Feb 2025 07:04:00 GMT

Hi,

If the device in pairing mode (observer?) is scanning aggressively and sending a scan request for every advertisement event, you may frequently encounter collisions between the scan request and the connection request. The solution is to attempt the connection again.

RE: peripherials fail to connect to central (nrf5340) if another central (nrf5340) is scanning nearby

Aravibala — Wed, 19 Feb 2025 05:56:33 GMT

hi vidar, thanks for the reply, the central can switch between two different mode;

pairing mode: that filters peripherals based on uuid and extract mac and store them;

connection mode: that filters based on the stored mac and gets connected to the peripherals that matches the mac addr and gets the data from the peripherals.

lets say two central are place next to each other and if one central device is in connection mode and gets data from the perhiperial that is already connected with the central.

Meanwhile if the other central device is in pairing mode and is near by, it affects the peripherial from sending the data to the central which it is already in connection with. we get this error in the debug log of the central .

Function connected (callback) called with conn_err: 2; Failed to connect to 50:33:8B:26:C5:30 (public)
Failure reason 2: connection create timeout
Refreshing scanning
Setting new scan filters for connecting mode based on target addresses and current active connections
Setting new scan filters for connecting mode based on target addresses and current active connections

Starting scanning

Filters matched. Address: 50:33:8B:26:C5:30 (public) connectable: 0
Therm discovered
Scanning stopped
Initiating connection with Thermometer

Function connected (callback) called with conn_err: 2; Failed to connect to 50:33:8B:26:C5:30 (public)
Failure reason 2: connection create timeout
Refreshing scanning

RE: peripherials fail to connect to central (nrf5340) if another central (nrf5340) is scanning nearby

Vidar Berg — Mon, 17 Feb 2025 14:49:26 GMT

Hi,

Are both centrals trying to connect the same peripheral? I assume the peripheral stops the connectable advertiser as soon as it has established a connection with one of them.

Best regards,

Vidar