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UARTE STOPRX on exact byte

Hi there,

I'm issuing a STOPRX at a specific time but I'm noticing that more bytes are being put into the buffer from after the STOPRX was issued.

Is there a way to stop the UARTE on the exact byte and process, and receive all bytes from that point on to a different buffer?

Please advise.

UPDATE

After triggering a STOPRX, the UARTE will hang around for a few more bytes, placing them in the same buffer and then calling ENDRX. This is problematic since these new bytes are part of a different message.

image description

Here you can see that STOPRX is triggered during some small idle times, yet the ENDRX doesn't happen till much later.

This results in ENDRX being called with 11, 6 and 1 bytes read (when it should be 6, 6 and 6 bytes read)

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  • No. The documentation addresses this. if you're using nRF52 (UARTE so I assume so) up to 4 bytes can be received after the STOPRX task. How many actually are depends on what's on the other end transmitting data to you, if it's slow stopping after the RTS signal is deactivated and keeps sending more data, the UARTE is going to receive it. I assume you're using hardware flow control.

    Those bytes however go into the RX FIFO so you can update the memory buffer pointer after you get the ENDRX event and then flush to start those bytes off in your new buffer.

  • I think the confusion here is that the delay between STOPRX and ENDRX event is because of the 4 bytes reception ability !!?? which I think is not correct. The ability to receive 4 bytes after STOPRX has nothing to do with the delay for ENDRX. As you said, the incoming bytes after STOPRX should stay in FIFO and I think that is how it will be. Otherwise FLUSHRX task would not make any sense to me. Do you agree?

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  • I think the confusion here is that the delay between STOPRX and ENDRX event is because of the 4 bytes reception ability !!?? which I think is not correct. The ability to receive 4 bytes after STOPRX has nothing to do with the delay for ENDRX. As you said, the incoming bytes after STOPRX should stay in FIFO and I think that is how it will be. Otherwise FLUSHRX task would not make any sense to me. Do you agree?

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