ble data sequence out of order

[lemon]

Hi,

I have a device that throughout the uart data to ble,recently I find a problem that in  the case of weak signals,the data sequence is out of order.

Here is the question:

The data sequence is 03-A7,03-A8 ...each packet add one,but as the picture shows,03-A8 and 03-A9 is behind of the 03-AA and 03-AB

Why is this happening?

BRs,

Lemon

[run_ar]

Hi,

Assuming you are sending notifications, when a notification is queued, it will stay in the queue until it is sent to the peer. So if the order is wrong it is more likely they are not placed in the tx queue in the correct order or that the log is buffered, and not printed in the correct order.

Could you capture a sniffer trace and check if the data is transmitted in the correct order? That would show us on which side the packet order is changed.

[lemon]

Hi，run_ar，

Attach is the sniffer log.

Here we can see:

The packet is 4C F0,4C F4,4C FF,and 4C F1,4C F2 and others are losed.

Then we scroll down to see the record:

Here we can see the 4C F1 and 4C F2 and others after 4F05.

If you need more information,you can ask me and I will send to you as soon as possible.

Thanks for your reply.

BRs,

Lemon

1021.btt

[run_ar]

Hi,

Seems the sniffer is not able to capture all the master packets. Did you place it inbetween the master and the slave?

Regardless it seems that something goes wrong in the application sending the packets. How do you buffer these in the application? how do you empty the buffer? And how do you handle the error messages from sd_ble_gatts_hvx?

The SD itself operates in a "first in, first out" manner, so the first packet that is placed in the tx buffer will be sent first on air.

[lemon]

Hi，

Attach is the log which use the nrf_connect get,and is same as the sniffer log.

The sniffer is nearby the salve device and the master (a phone) is in the pkace where the RSSI is between -95 to -100 dB.

I will check the software if there is any problem.

If there is any progress, I will inform you immediately.

7ba992c671b85b98d34780a19ce50dd3.txt

[lemon]

Hi,

I have found the issues.

Thanks for your reply.

[run_ar]

Thanks for letting us know. Glad you figured it out.