UARTE/Zephyr ASYNC API

RE: UARTE/Zephyr ASYNC API

lanwer — Tue, 04 Jun 2024 07:23:59 GMT

I can recommend you this lesson from the DebAcademy. I was able to use the Async Api successfully following it: Link

I also found this youtube video super helpful: UARTE Async

RE: UARTE/Zephyr ASYNC API

Einarh — Fri, 10 Mar 2023 14:38:16 GMT

Ok, then I will close this ticket.

If you need more support for the callback in the future, please open a new ticket where you describe your current situation.

Best regards, Einar

RE: UARTE/Zephyr ASYNC API

Martin Thompson — Thu, 09 Mar 2023 16:49:30 GMT

I have successfully used the blocking uart RX function from the nrfx_uarte drivers :) This is sufficient for my current work. I may have to return in future as I still cannot get the DMA driven callback to work :(

RE: UARTE/Zephyr ASYNC API

Martin Thompson — Thu, 09 Mar 2023 11:01:33 GMT

Hi again,

Thanks for clarifying further on the various driver options. Yes, I may be using the wrong end of the driver! It was not clear to me that prj.conf applies outside of the Zephyr context as well - I will try that later today 🙂

Any thoughts on why I do not get any READY events in my handler would be gratefully received!

Thanks

Martin

RE: UARTE/Zephyr ASYNC API

Einarh — Thu, 09 Mar 2023 10:08:56 GMT

Hi again

I agree the Zephyr drivers *should* work, I was suggesting to try the nrfx driver mostly to see if you got any more helpful debug/error messages out of them.

[quote user="Martin Thompson"]It does not link, presumably I have to tell the tools I need another library.[/quote]

I would suspect that perhaps you'll have to enable your nrfx_uarte peripheral in prj.conf for it to link?

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/kconfig/index.html#CONFIG_NRFX_UARTE0

Or it could be that you're seemingly using the hardware access layer driver instead of the actual uarte driver, which can be found at /v2.2.0/zephyr/drivers/serial/uart_nrfx_uarte.c

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfx/drivers/uarte/index.html

[quote user="Martin Thompson"]Some progress with the original problem using the Zephyr API: don't make your Rx buffer too big... 256 bytes does not work[/quote]

Glad to see you made progress with the Zephyr API, the 8-bit limitation comes from the maximum size of the uarte receive buffer:

https://infocenter.nordicsemi.com/index.jsp?topic=%2Fcom.nordic.infocenter.nrf52832.ps.v1.1%2Fuarte.html&cp=5_2_0_34_9_12&anchor=register.RXD.MAXCNT

I'm not sure off the top of my head why you wouldn't get the READY events through to your handler, but I'll look into it.

[quote user="Martin Thompson"]the combination of confusions between SDK/rfconnect, Zephyr/non-zephyr, new/old UART, UARTE/UART drivers makes it *incredibly* difficult to find answers for yourself.[/quote]

I agree this is intimidating when getting into this environment, but I think it mostly comes down to the documentation not always making it obvious what is new/old or common/fringe.

SDK/nRFConnect: The nRF5 SDK is old and outdated, don't use it. NCS (nRF Connect SDK) with Zephyr is what our developers are working on these days and will always be more up to date.

Zephyr/non-Zephyr: I would recommend always using Zephyr's drivers, and would only suggest using our drivers by themselves for debugging as they are being used under the hood when using Zephyr.

UARTE/UART: UARTE is simply UART with EasyDMA, meaning data is sent directly from/to ram without cpu intervention. UART is normal good old UART. UARTE is default, and I would recommend using it, especially if you're using BLE, as using EasyDMA can help you avoid BLE and UART fighting for CPU priority.

Best regards,

Einar

RE: UARTE/Zephyr ASYNC API

Martin Thompson — Wed, 08 Mar 2023 20:12:43 GMT

Some progress with the original problem using the Zephyr API: don't make your Rx buffer too big... 256 bytes does not work (I think because the hardware only has an 8-bit counter - an error for this from the driver would be... helpful!) . Now I don't get the extra END event. but the READY events are now not getting through to my handler...

RE: UARTE/Zephyr ASYNC API

Martin Thompson — Wed, 08 Mar 2023 19:54:17 GMT

I'm pretty sure there should be a 'correct' way to do this, but my hacky workaround for now is:

target_sources(app PRIVATE src/main.c c:/app/ncs/v2.2.0/modules/hal/nordic/nrfx/drivers/src/nrfx_uarte.c)

in CMakeLists.c 😞

RE: UARTE/Zephyr ASYNC API

Martin Thompson — Wed, 08 Mar 2023 19:40:29 GMT

So, i have tried to use nrfx_uarte* directly. It does not link, presumably I have to tell the tools I need another library. So now I have a different problem. After scouring the documentation for another hour, I can't find what I need to there either. I really felt that as an experienced embedded engineer I would be able to make something this straightforward work, but the combination of confusions between SDK/rfconnect, Zephyr/non-zephyr, new/old UART, UARTE/UART drivers makes it *incredibly* difficult to find answers for yourself. So I am at the mercy of whoever reads this and might offer me a ray of light! Simple examples which demonstrate (in a reusable way) how to operate the peripherals are also tricky to find - everything seems to depend on starting from a working sample, but then adding features to that is a shot in the dark (as far as I can see)...

Thanks,

Martin

RE: UARTE/Zephyr ASYNC API

Martin Thompson — Wed, 08 Mar 2023 14:59:40 GMT

Hi Einar, no I haven't. It seemed to me that as I was using an RTOS (Zephyr) I should expect its features & APIs to work (given that they appear to be integrated with the nrf drivers) and that therefore would be the best way. I didn't want to get into everything at the driver level.

Perhaps *that* is where I made a mistake! Is this not recommended?

Thanks
Martin

RE: UARTE/Zephyr ASYNC API

Einarh — Wed, 08 Mar 2023 14:55:01 GMT

Hello!

Have you tried using the nrfx_uarte_rx function directly?

Best regards,

Einar