nRF58232 UARTE RX EasyDMA Pointer

RE: nRF58232 UARTE RX EasyDMA Pointer

ovrebekk — Fri, 27 Apr 2018 12:49:45 GMT

I am happy to help, the best of luck with your project 🙂

RE: nRF58232 UARTE RX EasyDMA Pointer

MPS — Fri, 27 Apr 2018 09:37:02 GMT

Many thanks for your answer. So I will do with what there is. probably with the PPI.

RE: nRF58232 UARTE RX EasyDMA Pointer

ovrebekk — Fri, 27 Apr 2018 07:49:44 GMT

The PPI controller is a very useful peripheral that allows you to pass various control signals (events) from one peripheral to another without requiring any processor activity. For more information I would suggest you read the PPI chapter in the product specification.

[quote user="Mickael P."]But I don't understand that we can't get the next address where will be stored the next byte received. The Processor knows it, so why is it not feasible to get this information ? I find it really bad ...[/quote]

This is just the way the UARTE peripheral is designed unfortunately. The processor doesn't know the next address, this is stored internally in the UARTE peripheral, and the UARTE peripheral doesn't expose any registers that would allow the processor to read this information while the UART RX is running.

Best regards
Torbjørn

RE: nRF58232 UARTE RX EasyDMA Pointer

MPS — Thu, 26 Apr 2018 15:36:21 GMT

Hi Torbjorn,

Thanks for your answer.

I didn't know PPI controller, I'll see that, if I've enough timer.

But I don't understand that we can't get the next address where will be stored the next byte received. The Processor knows it, so why is it not feasible to get this information ? I find it really bad ...

RE: nRF58232 UARTE RX EasyDMA Pointer

ovrebekk — Thu, 26 Apr 2018 14:59:52 GMT

There are basically two ways to know how many bytes have been written to the buffer:

a) Stop the RX by activating the STOPRX task, wait for the ENDRX event to occur, and read the number of bytes read in the RXD.AMOUNT register.
Since the RX pointer is double buffered you can pre-load the next buffer to be used, and use the ENDRX_STARTRX shortcut to start the RX immediately following the ENDRX event.

b) Count the number of RXDRDY events using a timer in counter mode and the PPI controller.

If b) is not an option you would have to go for a)

For more information on the UART receive mechanism, you can look here.

Best regards
Torbjørn