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UARTE STOPRX on exact byte

parco

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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  • 0

    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.

  • 0 in reply to RK

    As I said, there are some thing which need clarification, and that's one of them. However I think that delay is just the uart waiting for another character, they don't have to be entirely back-to-back, there is a timeout. So you've started a transfer asking for n bytes and it's doing its best to fulfil that.

    I think your use case, now you've described it, is something you just can't really do like this, stopping it at a random time and hoping to get the exact number of bytes left in the buffer. I wondered about setting the byte count to '1' and updating the pointer every byte, that might make it stop instantly after the STOP task as it has nothing else to do, not sure that would work either however.

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  • 0 in reply to RK

    As I said, there are some thing which need clarification, and that's one of them. However I think that delay is just the uart waiting for another character, they don't have to be entirely back-to-back, there is a timeout. So you've started a transfer asking for n bytes and it's doing its best to fulfil that.

    I think your use case, now you've described it, is something you just can't really do like this, stopping it at a random time and hoping to get the exact number of bytes left in the buffer. I wondered about setting the byte count to '1' and updating the pointer every byte, that might make it stop instantly after the STOP task as it has nothing else to do, not sure that would work either however.

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