KW36: Read response takes ~2 seconds

[skalyan2]

Hello,

I have totally 8 attributes(5 - Custom attributes, 3 - Standard attributes) in my att database, when we try to read the charateristic value attribute by read request from my android app/any app, nxp host/controller stack almost takes ~1.5 - 2 seconds to give the read response of one characteristic from KW36 ATT stack.

Can you please provide analysis for the above ?

This is major blocker for us since it takes lot of time to read entire characteristic value attribute, please respond to this asap.

Please get back in case of any queries. 

Regards

Sai Kalyana Raman

[Xiang_Li]

Hi Sai Kalyana Raman,

Please provide your connection parameters, e.g. connection intervals etc.

If you have a BLE sniffer please take a sniffer log and post it. That would help a lot. Thanks!

Regards,

Xiang

[skalyan2]

Hi xiangli‌,

My connection parameters are :

Connection interval : 15ms, slave latency : 100 , supervision timeout :12500ms and for the remaining, please refer the attached airtrace. I have bookmarked the frames which has the issue, in this attached log , it takes ~1.5 seconds for reading one att value characteristics. Please provide your immediate support here as mentioned above.

Many thanks in advance.

Regards,

Sai Kalyana Raman

[Xiang_Li]

>> Please provide your immediate support here as mentioned above.

Please try to change slave latency from 100 to 1 and see if it make any difference. And let me know.

[Xiang_Li]

In fact, slave latency can be 0, so please change it from 100 to 0 and try again.

[skalyan2]

Hello xiangli‌,

Thanks for your instantaneous reply, this resolved my issue :smileyhappy: , 
Can you please lend your support by having a look at this ticket "https://community.nxp.com/message/1211832?commentID=1211832#comment-1211832 " also and provide us a solution as that is also very crucial for me.

Many thanks in advance.

Regards,

Sai Kalyana Raman

[Xiang_Li]

Hi Sai Kalyana Raman,

Slave latency is a parameter that allows a BLE slave device to skip N connection events. If you connection interval is 15ms, slave latency is 100, it means the slave device is allowed to sleep for 15ms * 100 = 1.5s. And then wakeup to exchange information with the master device.

If we change slave latency to 0, it means the slave device must stay active and response a packet every 15ms. The response time is reduced largely, in trade of power consumption. If your slave device is battery powered, please consider carefully about how to find best parameters for connection interval, slave latency, response time.

Regards,

Xiang

[skalyan2]

Hi nxa20520‌

Many Thanks :smileyhappy:

I am using LE 1M phy, i have set connection paramets currently as: 

Connection interval minimum: 30ms

Connection interval maximum:50ms

Slabe latency : 0

Supervision timeout: 5000ms

I have set this connecion parameters only in ppcp(peripheral preffered connection parameters) characteristics and i want to know if i want my controller by default to take this values in the boot time/after startup, where should i set this values in kw36 sdk? Why i ask this is apple ios does not read ppcp characterisitcs and it  will take default values which we set in gap, how to set the gap default parameters?? 

Is these are the only things i need to consider in connection parameters or is there anything i need to consider?

Also is the above values are preferred??

Thanks.

Regards,

Sai Kalyana Raman