how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

ovrebekk — Tue, 14 Jan 2020 15:03:22 GMT

You should post unrelated questions like this in a new case, rather than adding it to an old one.

Then you get a quicker response, and avoid adding clutter to the existing case.

The device family packs we publish are added here:
https://developer.nordicsemi.com/nRF5_SDK/pieces/nRF_DeviceFamilyPack/

I see that 8.27.0 is not available, but you should be able to use 8.27.1 instead.

Best regards
Torbjørn

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

TODOALL — Wed, 08 Jan 2020 06:54:01 GMT

Hello, I used SDK 16.0.0, but compiled in keil and found that nRF_DeviceFamilyPack_NordicLicense.8.27.0 is missing, but the official website did not find the download link for this

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

ovrebekk — Thu, 05 Dec 2019 14:13:58 GMT

I will let Jørgen handle your case, but with the double buffer implementation used in the nrf_libuarte driver this should not be an issue.

All you have to do is make sure the buffer size is scaled according to how long the UART interrupts could be delayed by higher priority interrupts.

Best regards
Torbjørn

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

thefool — Tue, 03 Dec 2019 17:19:38 GMT

Hi,
I just found this thread after posting this question:
https://devzone.nordicsemi.com/f/nordic-q-a/55117/safe-uart-line-idle-detection-with-dma

about 2 years ago, in the solution proposed at that time, there was a chance of losing some bytes.

Is the solution, as implemented in the new driver 100% safe to use?

Lets say the DMA size is 32 bytes, and the timeout is 5ms
We then receive packet A with 25 bytes, then there is a pause of just over 5ms and another packet (B) with 25 bytes comes in.

The timer should fire after 5ms, and we get to handle the data. but immediately following the timer, the next set of data comes in.

Is there a chance we lose any of that data?

(in the solution proposed last time we asked, the timer would send the STOPRX event, which would then cause a timeout, the length of 4 bytes to start, then fire the RXTO event, in which one should call FLUSHRX, which would cause the EasyDMA to copy the data and send the ENDRX event (which might restart STARTRX, depending on your configuration). in that timeout of 4 bytes, any new incoming data might overwrite the old data before FLUSHRX could copy it.

Is that problem solved?

Do you ahve a diagram similar to this one for the the inactivity handling?
https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf52832.ps.v1.1/uarte.html#concept_uzb_p2m_wr__fig.stoprx

Thank you!

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

Taoo — Thu, 28 Nov 2019 13:14:15 GMT

Oh！Thank you very much!Help me a lot!

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

ovrebekk — Wed, 27 Nov 2019 10:32:46 GMT

If you need to stay on SDK v15.0.0 it should still be possible to copy the lib_uarte driver from SDK v16.0.0, so that you can take advantage of the latest version of this driver.

Also, I would strongly recommend migrating to SDK v15.3.0 even if you find it too much work to go all the way to SDK v16.0.0.

SDK v15.3.0 should be compatible with SDK v15.0.0, but contains a number of improvements and additions compared to v15.0.0.

Best regards
Torbjørn

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

Taoo — Tue, 26 Nov 2019 09:41:21 GMT

but could i easly to achieve in SDK v15.0.0?because many user codes had exist in my project.It maybe cost more time for me to migrate to SDK v16.0.0?

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

Taoo — Tue, 26 Nov 2019 09:35:21 GMT

Oh!I seen in SDK v16.0.0,thank you very much!

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

ovrebekk — Tue, 26 Nov 2019 07:59:20 GMT

This problem is solved by the nrf_libuarte_async driver. It uses a timer to detect inactivity on the UART, and generates an interrupt even if the UART buffers are not full.

Then you can define a timeout period, and if no more data is received during this time you will still get an event from the driver with the currently received data.

Best regards
Torbjørn

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

Taoo — Mon, 25 Nov 2019 13:47:24 GMT

Thank you very much for your answer, but I don't think it can solve my doubts very well.

My problem is——only until dma buffer fill up, can i get event and read data from buffer?what the suitable size of RXD.MAXCNT should be setted?if setting 5 bytes,a frame with 6 bytes will not completely received?because when received 5 bytes,buffer fill up,switch to another buffered for received.but there remain 1byte,so the dma buffered will not fill up.Upper layer could not get a complete frame.

RE: how to use uarte in 1M baud. RXD.AMOUNT will not update until fill up rxbuffer?

ovrebekk — Mon, 25 Nov 2019 12:56:54 GMT

I would strongly suggest using the nrf_libuarte driver available in the SDK. It is designed to allow efficient use of the DMA buffers with the UART, and is double buffered to ensure that you don't drop any data when the buffers fill up.

You can read more about this driver here.

I would also recommend migrating to SDK v16.0.0 if you can, to get the latest version of the driver.

Best regards
Torbjørn