nrf52840 slow rx characteristic time

[_maibi]

The nRF52840 has a longer rx characteristic reception time than the nRF51822.

 --> android terminal log

first and second line nRF52840 , It takes almost 1.2 seconds to get the rx characteristic.

below nRF51822, It takes almost 0.4 seconds.

why It happens? What should I do to improve the performance?

NRF52840 -

SDK 15.3.0, with buttonless dfu service

NRF51822 - 

SDK 12.3.0 - w/o buttonless dfu service

Other application layer are almost same.

[Simonr]

Hi

I believe this might be due to different connection parameters (intervals, etc.) in the two SDKs. I think this was done to minimize the current consumption, which causes events to be a bit longer. You can try setting the same connection parameters for both devices and compare, to see if this is correct.

Best regards,

Simon

[_maibi]

... I did double check. connection parameter is same.... and I tested ble app uart example in sdk. It also takes 1 sec. I think that there are big different nrf51 and nrf52. for now I dont have idea. parameter... or etc...

[_maibi]

galaxy note 4

It takes almost 1.1 sec.

It takes almost 0.3 sec.

*different phone, More recent model. galaxy note 10

It takes almost 0.5 sec.

It takes almost 0.8 sec.

note10 is faster than note4 in average time, but the pair of galaxy note 4 & nrf51 is fastest speed to discover service.

and nrf52 is slow for all. Is it normal?

[Simonr]

Hi

Okay, it seems I misunderstood the initial question. Sorry about that. This delay happens after the devices have connected, right? Can you provide a sniffer log so we can take a look at what happens? You can do this either by using an Ellisys sniffer (if you have one available) or by using an extra nRF52 DK and the nRF Sniffer to sniff the connection.

You can also try setting NRF_LOG_DEFERRED to 0 in order to minimize the delay from an event until it is printed, as the terminal log might not be the most reliable way to measure the time it takes to get a service.

Best regards,

Simon

[_maibi]

thanks to reply!

here are the logs.

nrf51822-galaxy-note10.pcapngnrf52840-galaxy-note4.pcapngnrf52840-galaxy-note10.pcapngnrf51822-galaxy-note4.pcapng