8-bit acorn hardware • Re: Z80 Protocol Decoder

I've set my HP to capture all those signals in that order, then edited the capture to take out all extraneous spaces and end up with this:

I've tried to post-process the "binary ascii" file into something the decoder should handle, but it doesn't make much sense.

Let me clarify that a bit...

The control bits make perfect sense, but the data bits look like they might be permuted somehow (and not simply reversed).

Do you think you could confirm they are connected as intended.

A couple of further thoughts...

To make sense of a capture from a suspect/possibly broken machine, it helps enormously if the capture starts from the "held in reset" state. So use reset as a trigger, but making sure the capture includes the 0->1 edge of reset.

It would also be less error prone if you can produce a raw binary file, which is what the decoder consumes. That file would ideally contain pairs alternating data and control bytes:I had to try to mangle your text file into this binary format and it was painful.

Dave

Statistics: Posted by hoglet — Thu May 22, 2025 11:55 pm

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