BLE peripheral is not getting disconnected

Vishal Nandanwar

Other Parts Discussed in Thread: CC2650MODA

Hello,

I am developing one gateway in which I have used BLE. This gateway is playing central role. I am using module CC2650MODA with Host test firmware.

I am observing that disconnection with the peripheral device is not proper. I am using GAP_TerminateLinkReq (0xFE0A) command with 0x13 as reason. 0x13 description is - Remote User Terminated Connection.
Irrespective of sending this command it is observed that peripheral device is not getting disconnected in correct way. It takes longer duration to disconnect or peripheral gets timed out.

Do I need to do any other thing to while disconnecting? is reason 0x13 is correct to disconnect from central device?

Vishal N

over 7 years ago

0 Christin Lee over 7 years ago

TI__Guru 56215 points

Hi,

It's correct reason to receive when Central terminates the link.

Regarding peripheral device timedout or takes long time to disconnect, can you provide sniffer log? What's the slave latency in your connection setup?

0 Vishal Nandanwar over 7 years ago in reply to Christin Lee

Intellectual 550 points

Hi Christin,

Slave latency = 0

Min Con Interval 16 msec

Max Con interval 16msec

Attached are the sniffer logs for successful connection as well failure case.

"Failure log.psd" contains the sniff for connection failed attempt.

"Successful read log.psd" contains the sniff for connection success attempt.

Successful read log.psd Failure log.psd

Vishal N

0 Christin Lee over 7 years ago in reply to Vishal Nandanwar

TI__Guru 56215 points

Hi,

In the failed log, before sending the link termination command, there are lots missing packets and master missed the packets that slave sent(lots of retry). Are you in an noisy environment?

The reason that it took long time to disconnect is that because master did not ACK on that link termination packet. (It's very likely that master miss that packet since it has been like this since P.nbr 2450)

0 Vishal Nandanwar over 7 years ago in reply to Christin Lee

Intellectual 550 points

So is this because of noisy environment?

My understanding is this retries happenings at BLE protocol level and application is not playing any role in it. Can I do anything in my application to avoid such situation?

Vishal N

0 Christin Lee over 7 years ago in reply to Vishal Nandanwar

TI__Guru 56215 points

I am guessing it's because of noisy environment, but it could also be the HW design(if you are using custom HW) is not giving you the best performance.

You can't avoid retrying since it's part of BLE protocol.

0 Vishal Nandanwar over 7 years ago in reply to Christin Lee

Intellectual 550 points

I am using CC2650MODA with host test.

Is there any suggestions/recommendations for default connection parameters at central side?

Vishal N

0 Christin Lee over 7 years ago in reply to Vishal Nandanwar

TI__Guru 56215 points

There is no one set of value that's recommended for central. You need to evaluate your end application and use case to decide the connection parameters.

Ex: If you are streaming audio, then you need to use short connection interval with 0 slave latency. However, if it's temperature reporting system, then you don't need frequent update. Thus you can use longer connection interval with high slave latency to save battery.

Again, you need to decide those parameters yourself.

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BLE peripheral is not getting disconnected