NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

youngwallaby — Tue, 03 Sep 2019 16:46:17 GMT

Jared,

I wanted to share what I found to be the problem. It looks like the sleep mode for this unit was not configured properly. Of the two sleep modes, Constant latency and low power, neither were explicitly chosen. Once the sleep mode constant latency was chosen and the boards were reprogrammed the issue with the bluetooth connection dropping went away.

Thank you for all of your help,

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

Jared — Mon, 12 Aug 2019 11:35:42 GMT

Hi,

Thank you for the sniffer trace. I can't see that the slave doesn't respond to packages with eventually causes a timeout. Did you try changing the LFCLK source? What PPM value do you use in the sdk config file? Are you able to replicate the issue with an example from the SDK, such as ble_app_uart example?

regards

Jared

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

youngwallaby — Thu, 08 Aug 2019 14:58:41 GMT

Jared,

I have captured a sniffer trance with the NRF Sniffer as described in the nRF Sniffer user Guide v2.2 document. That file is attached here: devzone.nordicsemi.com/.../NRF-Sniffer-Trace.pcapng

I will try changing teh LFCLK source to the LFCLK to the RC oscillator and let you know if that fixes the problem.

Thanks,

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

Jared — Wed, 31 Jul 2019 15:07:44 GMT

Hi,

Please provide a sniffer trace with the nRF Sniffer if possible. Could you try changing the LFCLK source to the RC oscillator and see if the problem persist?

Jared

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

youngwallaby — Tue, 30 Jul 2019 14:12:48 GMT

Jared,

Attached are the datasheets for the crystals.

I used the Bluetooth snoop hci log feature of androids development tools. We currently do not have a nRF sniffer but can acquire one if that is necessary.

devzone.nordicsemi.com/.../ABS06_2D00_107_2D00_32.768kHz_2D00_T.pdf devzone.nordicsemi.com/.../c_5F00_NX2520SA_2D00_STD_2D00_CSW_2D00_4_5F00_e.pdf

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

Jared — Tue, 30 Jul 2019 13:38:27 GMT

Hi,

Could you provide the datasheet for the crystals that you're using? What sniffer have you used? Could you provide a sniffer trace that uses the nRF sniffer? The sniffer log you attached doesn't showcase the issue, and the connection in the log is disconnected after a disconnect is sent by the host.

regards

Jared

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

youngwallaby — Fri, 26 Jul 2019 16:32:04 GMT

Here is the Bluetooth log file:

devzone.nordicsemi.com/.../6740.btsnoop_5F00_hci.log

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

youngwallaby — Fri, 26 Jul 2019 13:40:53 GMT

Hello Jared,

I will capture the sniffer trace of the connection shortly. In the mean time I have the schematic attached below. The 32kHz crystal being used is a Abracon Corporation ABS06-107-32.768KHZ-T. The 16MHz crystal being used is a NDK NX2520SA-16MHZ-STD-CSW-4. I will request the layout files and get those to you as well.

Thanks,

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

Jared — Thu, 25 Jul 2019 12:23:49 GMT

Hi,

Are you able to provide a sniffer trace of the connection between the faulty unit and the Iphone? Could you share the schematics and layout files of the custom board, and also specify which crystal that you're using.

regards

Jared

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

youngwallaby — Wed, 24 Jul 2019 16:24:03 GMT

Awneil,

The soft reset is described in the nrfjprog command line toolkit:

nrfjprog -r : performs a soft reset by setting the SysResetReq bit of the AIRCR register of the core. The core will run after the operation.

device connected is an IPhone application. The system does recover the connection after a span of 1-3 seconds. This problem does not exist in the other 95% of the product. A bluetooth signal strength application was installed on an Android device. The signal strength does not appear to be any less than the 95% of units that do not present this problem.

The oscillator was probed on a "bad" unit and it appeared to be operating normally. Could it be that the oscillator is the issue? We could try replacing the component.

Thank you for your feedback

RE: NRF51822 boards with bluetooth connection issues are fixed with soft reset but not pin reset

awneil — Wed, 24 Jul 2019 16:14:25 GMT

To find a solution, you first need to find what the actual problem is!

Instrument you code, and look for what's different between the two situations.

[quote userid="81953" url="~/f/nordic-q-a/50208/nrf51822-boards-with-bluetooth-connection-issues-are-fixed-with-soft-reset-but-not-pin-reset"]perform a "soft reset" using the nrfjprog[/quote]

What, exactly, do you mean by that?

[quote userid="81953" url="~/f/nordic-q-a/50208/nrf51822-boards-with-bluetooth-connection-issues-are-fixed-with-soft-reset-but-not-pin-reset"]a dropping of the Bluetooth connection randomly[/quote]

And what, exactly, is going on there?

Are there any other issues with these units - such as low received and/or transmitted power? Oscillator stability/accuracy? etc ...

With any radio link, you have to be prepared for it to drop "randomly" - is your real problem that it doesn't recover after dropping?