nrf52 fails to transmit 20bytes data at 100Hz

RE: nrf52 fails to transmit 20bytes data at 100Hz

jpo38 — Thu, 28 Feb 2019 10:26:53 GMT

Hello Kenneth.

The problem is still present for us. Some time ago we tried to replace the dongle by a dev board but we never succeeded to make it work.

However, I worked again on this issue and could isolate something very wierd. Windows activity has apparently an impact on the actual data rate at which data can be retrieved. Please have a look at :

stackoverflow.com/.../using-a-qt-vista-style-widget-makes-my-ble-data-acquisition-faster-why

If this inspires you....

RE: nrf52 fails to transmit 20bytes data at 100Hz

Kenneth — Mon, 09 Apr 2018 15:21:15 GMT

I should mention that in addition to downgrade the driver, you also need to downgrade (roll-back) the firmware. This can be done by open "J-Link Configurator" and replace firmware.

RE: nrf52 fails to transmit 20bytes data at 100Hz

jpo38 — Fri, 06 Apr 2018 12:08:24 GMT

Just tried that, but it also uses driver 6.0.2601.5. I even downgraded to the oldest version (5.00), it also uses driver 6.0.2601.5 and has the same issue...

RE: nrf52 fails to transmit 20bytes data at 100Hz

Kenneth — Thu, 05 Apr 2018 15:01:20 GMT

Can you try to downgrade to an older SEGGER driver, such as 6.16c, and see if there is any difference:

https://www.segger.com/downloads/jlink/JLink_Windows_V616c.exe

RE: nrf52 fails to transmit 20bytes data at 100Hz

jpo38 — Thu, 05 Apr 2018 07:20:32 GMT

Thanks for your help, we can try to swap, but it's hard to say how hard this will be. I checked and we use the latest SEGGER driver, so we can't expect a potential driver issue to be fixed.

RE: nrf52 fails to transmit 20bytes data at 100Hz

Kenneth — Wed, 04 Apr 2018 19:12:45 GMT

I can see from the logs that the central starts nacking packets, which may indicate it is not able to push data through the UART fast enough for unknown reason. Could be an issue in the SEGGER driver, it could help if you can either create a logic analyzer trace of the UART pins (e.g. using https://www.saleae.com/), alternatively you can swap out the SEGGER chip with another USB to UART bridge (e.g. ftdi chip). Are you able to do either?

RE: nrf52 fails to transmit 20bytes data at 100Hz

jpo38 — Tue, 27 Mar 2018 06:04:15 GMT

Just tried that and updated my original post. I get surprising results (seeing more notifications from wireshark when nrf_heart_rate_collector reports less data received). I m' not familiar with those protocol layers, so I can't tell if some "extra notifications" were actually errors being reported. So I attached the wireshark output files, I counted the events during the 7's second of log.

RE: nrf52 fails to transmit 20bytes data at 100Hz

Kenneth — Mon, 26 Mar 2018 18:18:42 GMT

Then my suggestion is to do an on-air sniffer log to compare the two cases:

http://www.nordicsemi.com/eng/Products/Bluetooth-low-energy/nRF-Sniffer/(language)/eng-GB

RE: nrf52 fails to transmit 20bytes data at 100Hz

jpo38 — Mon, 26 Mar 2018 12:20:29 GMT

Hello Kenneth, no it does not make any difference. They are always very close, 10cm to 20cm, not more.

RE: nrf52 fails to transmit 20bytes data at 100Hz

Kenneth — Mon, 26 Mar 2018 12:05:13 GMT

Hi, is there any difference if you place the dongle and peripheral very close together?