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utility to convert HP/Agilent logic analyzer captures to VCD


Eric Smith

Jan 1, 1970
I was very surprised to find that there didn't seem to be any software
to convert data captured from an HP/Agilent logic analyzer to VCD
format for use in a waveform viewer (e.g., GTKWave), so I wrote one:

I hope this may be useful to others.

I needed it because I was using a 16500B with a 16555A card, which can
capture 1M samples (2M in half-channel timing mode). But the poor
little 16500B doesn't have enough CPU power to process that many samples
reasonably in waveform display mode, so every time you turn the knob
to scroll or zoom, it takes a long time for a display update.

Maybe someday I'll be able to afford a newer logic analyzer, but for
now this helps a lot.

Just transferring the data out of the analyzer is really slow, even
with the optional Ethernet interface. The analyzer creates a separate
file for each signal. Although my converter will work with as many
separate signal files as you want, I've found that it's fastest to
add an extra signal to the analyzer that includes all of the bits of
interest, and display it as hexadecimal. Then you only have to extract
that one file from the analyzer (and optionally the time_abs.txt file).