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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 unfortunately do not have the ability to use hardware flow control on the peer device. Is it possible to set up some fake RTS CTS on the nrf chip that will force ENDRX to fire early?

    Also, you're saying the ENDRX is being delayed because the peer transmitter is still sending data, yet on the last STOPRX task no data is being transmitted and it is taking just as long for ENDRX.

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  • I unfortunately do not have the ability to use hardware flow control on the peer device. Is it possible to set up some fake RTS CTS on the nrf chip that will force ENDRX to fire early?

    Also, you're saying the ENDRX is being delayed because the peer transmitter is still sending data, yet on the last STOPRX task no data is being transmitted and it is taking just as long for ENDRX.

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