nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

nefen — Wed, 13 Dec 2023 17:29:28 GMT

I had the same issue with nrf52832.

I used two buffers for swapping.

I had 2 buffers of size 4 and I was expecting a message with 6 bytes.

After the buffer was full I received the first 4 bytes (as expected) and the buffer was full.

I got the UART_RX_BUF_RELEASED and UART_RX_BUF_REQUEST and handling the last event I swapped the buffers.

Then I got the UART_RX_RDY, but instead of receiving the 2 remaining bytes, I received only one.

The 6th byte wasn't lost. It just didn't raise the UART_RX_RDY event.

After I requested the next bunch of 6 bytes, the first byte that arrived was the one missing from the previous message. Nothing was lost, but I couldn't find any way to overcome this bug, as I had to initiate the next exchange of data to get the last bytes from the previous...

The problem has been solved after including in prj.conf the following (asHåkon Alseth suggested):

CONFIG_UART_0_NRF_HW_ASYNC=y

CONFIG_UART_0_NRF_HW_ASYNC_TIMER=1

#CONFIG_NRFX_TIMER=y (this was not accepted for nrf52832, it was by default activated and I had no access)

CONFIG_NRFX_TIMER1=y

I post this just to thank WaStefan and Håkon Alseth !

And, for anyone else that runs on the same issue.

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

Håkon Alseth — Wed, 17 Mar 2021 12:19:33 GMT

Hi,

[quote user="WaStefan"]

Thank you very much, it builds now with this configuration.

Everything works now, when using Hardware RX byte counting. I don't loose any bytes.

Thank you again for your help!

I will use this configuration from now on.

[/quote]

This is great to hear! I'm happy to help and glad to hear that the issue has disappeared!

Kind regards,

Håkon

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

WaStefan — Wed, 17 Mar 2021 12:11:45 GMT

Hello Håkon,

Thank you very much, it builds now with this configuration.

Everything works now, when using Hardware RX byte counting. I don't loose any bytes.

Thank you again for your help!

I will use this configuration from now on.

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

Håkon Alseth — Wed, 17 Mar 2021 11:34:55 GMT

Hi,

[quote user="WaStefan"]

CONFIG_UART_0_NRF_HW_ASYNC=y

to my prj.conf file, but I can't build my application anymore.

In Kconfig.nrfx it says that Hardware RX byte counting requires a timer instance and one PPI channel.
What do I have to do, to properly enable this feature?

[/quote]

Try setting this in your prj.conf to get it to build properly:

# Async
CONFIG_UART_0_ASYNC=y
CONFIG_UART_0_NRF_HW_ASYNC=y
CONFIG_UART_0_NRF_HW_ASYNC_TIMER=1
CONFIG_NRFX_TIMER=y
CONFIG_NRFX_TIMER1=y

Kind regards,

Håkon

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

WaStefan — Wed, 17 Mar 2021 08:09:05 GMT

I have seen the option of using hardware rx counting with the UART_0_NRF_HW_ASYNC kconfig option. How do I use this properly?

I tried to just add

CONFIG_UART_0_NRF_HW_ASYNC=y

to my prj.conf file, but I can't build my application anymore.

In Kconfig.nrfx it says that Hardware RX byte counting requires a timer instance and one PPI channel.
What do I have to do, to properly enable this feature?

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

WaStefan — Wed, 17 Mar 2021 07:44:20 GMT

With the changes to the code in uart_nrfx_uarte.c according to the PR, the UART driver doesn't really work anymore.

I only get a RX_RDY event when the first buffer is full and not as I want for every data paket I receive.

Right after the first RX_RDY event I get a second RX_RDY event for the second buffer, but it says this second buffer is also full, which is not true.

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

Håkon Alseth — Tue, 16 Mar 2021 13:38:21 GMT

Hi,

I am having issues reproducing your behavior consistently at my end. after extending the rx-timeout window; the issue went away at my end.

The issue you're seeing more consistently might be related to this one:

https://github.com/zephyrproject-rtos/zephyr/pull/25975

which has the corresponding issue report:

https://github.com/zephyrproject-rtos/zephyr/issues/33280

Could you try the proposed fix in the PR, and see if this has an impact on your end?

Kind regards,

Håkon

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

WaStefan — Mon, 15 Mar 2021 07:39:03 GMT

Hi Hakon,

I tried it with 10ms, 50ms and 100ms now, but still the same behaviour...

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

Håkon Alseth — Fri, 12 Mar 2021 15:19:05 GMT

Hi,

Could you try increasing the timeout here?

ret = uart_rx_enable(uart_dev, rx_buf0, 64, 10);

For instance to 50 ms.

I suspect that the PC sends with a small delay between each byte, causing the timeout to occur.

Kind regards,

Håkon

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

WaStefan — Fri, 12 Mar 2021 08:06:57 GMT

Yes I am sure. I know that I have sent "abcdefghi\r" and you can see in the memory window that "abcd" is in buffer0 and "efghi\r" is in buffer1.
Also the buffers are initialized with Zeros and this was the first time receiving in those buffers, so there is no "old data" in the buffers.

RE: nRF9160 UART: Loosing data when RxData is split into 2 buffers (Async API)

Håkon Alseth — Fri, 12 Mar 2021 08:00:25 GMT

Hi,

[quote user=""]So all the data is received and correctly stored in the memory, but the second RX_RDY event for the second buffer only gives me 1 byte, even though there are more…[/quote]

Are you sure that this is "new" data, and not the old value of the buffer?

Kind regards,

Håkon