Dongle in server mode with connect needs 100-400 ms to answer Read or Write response

[jean-marc]

Using a Peripheral set in Central mode and write then read data back in the Dongle nRF5240 set in Server Mode.

Once connected and exchange MTU (extended) I write and then read my data. The read response or the write response are very long up to 400 ms for the read response.

Sending 1 byte or 240 bytes does not make any differences.

Why is this delay for?

My Interval connection is set to the minimum 7.5 ms.

Are this timing correct? Can I made then shorter?

Thank for helping.

Jean-Marc

[Edvin]

Hello Jean-Marc,

I am a little confused. Can you clear up for me whether the dongle is a central or peripheral, and what is the other device? A cellphone or another chip?

Do you use notification or indication? And which device is writing(central or peripheral), and which device is reading(peripheral or central)?

Best regards,

Edvin

[jean-marc]

Thank you...

The Nordic dongle is used as peripheral/server, I setup my server parameters and used another device as central to read/write it.

The central is a CC2640R2 and I deal without any problems with both units. The only problem is the time for a response after the writerequest or the readrequest, it is about 100-400ms and I have no idea what the dongle is doing to answer with such delay.

Is this part of the BLE that the server needs a turnaround time to answer?

Both device are close each other.

jean-marc

[Edvin]

Hello Jean-Marc,

Is it possible to provide a sniffer trace? If you have a spare nRF DK you can use the nRF Sniffer. 

Please see this blog post.

The delay that you describe seems a bit long. A sniffer log would probably tell us what the devices are waiting for.

Is this something you use to send a lot of data, or something you typically use in the start of the connection?

BR,

Edvin

[jean-marc]

I will try the Sniffer.

I am testing the throughput, because I will have to transfer a lots of data and it has to be BLE.

Thank you for the hint, I will come back if I found a solution.