nRF9160 BLE Gateway using nRF52820

RE: nRF9160 BLE Gateway using nRF52820

Albrecht Markus Schellenberger — Wed, 27 Apr 2022 11:28:50 GMT

[quote user="esisk"]I let my HW team know to possibly include two extra lines for UART communication in future board revisions, so we can utilize the low power UART driver. The software choice of the split BLE stack was not known to us at the time of HW design, so we didn't take it into account. [/quote]

Thanks a lot for your feedback, Ethan. Yes, that makes totally sense. But I’m glad to hear that you were able to find a solution that might work for you anyway :-)

Cheers,

Markus

RE: nRF9160 BLE Gateway using nRF52820

esisk — Tue, 26 Apr 2022 12:42:13 GMT

No worries Albrecht, I appreciate your help. I actually tested that yesterday, a baud rate of 115200, and the bug has not resurfaced. I'll keep an eye on it but I think the problem just boiled down to the baud rate I was using was too high. I let my HW team know to possibly include two extra lines for UART communication in future board revisions, so we can utilize the low power UART driver. The software choice of the split BLE stack was not known to us at the time of HW design, so we didn't take it into account. Thanks again for your suggestions Albrecht

RE: nRF9160 BLE Gateway using nRF52820

Albrecht Markus Schellenberger — Tue, 26 Apr 2022 10:28:47 GMT

Hello Ethan,

First of all, my apologies for the delayed reply.

[quote user="esisk"]The ticket I mentioned above states that HW flow control is not required for the hci_lpuart sample.[/quote]

Our development team has tested HCI over UART with baud rates up to 115200 kb/s and that seems to work fine. However, without flow control there is a bigger chance of loosing bytes, and HCI does not implement mechanisms to recover from this. So you can basically end up in any bad state, which might explain the error you are facing.

My recommendation would be to test with baud rates < 115200 kb/s and see if that works ok.

Regards,

Markus

RE: nRF9160 BLE Gateway using nRF52820

esisk — Fri, 22 Apr 2022 13:30:42 GMT

Hey Albrecht, unfortunately it's not possible for our production application to run on a board that supports HW flow control. Our PCB design has been finalized and we're going to start production soon. I do have some development kits at my office, it'd be quite the task getting the app to run on there though. The ticket I mentioned above states that HW flow control is not required for the hci_lpuart sample.

RE: nRF9160 BLE Gateway using nRF52820

Albrecht Markus Schellenberger — Fri, 22 Apr 2022 12:33:21 GMT

Hello Ethan,

[quote user=""]Any guidance would be appreciated[/quote]

I’m not sure if it is possible to run HCI via UART without HW flow control enabled. The HCI UART sample in Zephyr states clearly, that it has to be enabled. I will check with our development team and see if I can get any more input.

Do you have the possibility to run your application on a board that supports HW flow control? It would be interesting to see if you face the same sporadic error there as well.

Regards,

Markus