HLA timeout using async serial

1

My issue: the last message is not rejected/recognized after a timeout

Using an async serial HLA decoder to decode bytes into messages. If a timeout after some bytes occur, there is no way to signal an improper message because there is no timeout (yes, there is, if after the timeout a new byte is on the line, but not if the capture is stopped before a byte arrives).

For example: message is 10 byte, but only 9 are received. The HLA has no way to detect a timeout condition without a byte after the timeout occurred? I canā€™t find anything I could set to signal a timeout occurred.

For example: is it possible to assign a timeout value to a HighLevelAnalyzer class? So the decode function is called with a timeout frame?

2

Perhaps what is needed is some form of signalling mechanism? One way to do this would be for class Hlaā€™s decode method to handle event frame types and to opt in for events through something like the settings system.

Interesting events might be TriggerEvent, TriggerMatch (fired anywhere a trigger event match is detected), Babble (ā€œfastā€ signal transitions for an extended period), Timeout (no signal transitions for an extended period), Glitch and so on.

3

Hi Herwin,

We do not currently support that use-case, but I agree itā€™s something we should look into supporting. We have a feature suggestion board at https://saleae.upvoty.com/b/feature-requests/, but I donā€™t think that one is in there. If youā€™d like, you can add it, otherwise Iā€™d be happy to.

Weā€™ve talked about adding an event for when the capture ends, so any pending state can be flushed, but this is a slightly different use-case. Do you have any thoughts on that?

Thanks!

Ryan

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4

I think that would also solve it. itā€™s just because the decode function is not called anymore that the frame does not get the possibility to publish the frame.

5

The addition of more events that would trigger the decode function in the HLA could also be a solution, and could be a pretty good addition to the software, but I guess itā€™s easier to implement (quick) to have the decode called at the end of a capture (event = ā€˜end of captureā€™).

6

Added an feature request at https://saleae.upvoty.com/b/feature-requests/hla-timeout-feature