Oop, straight out the blocks, an epic fail on this one!
so to generate a lookup table, I need my digipot's 256 linear step converted to log.
So I use the Excel log function to log 256 number & then charted it within Excel, the problem is, I get a plot like the No4 trace in the first chart/diagram about halfway down this page (ie a reverse log characteristic), whereas what I want is a trace like no2 on that same diagram
http://www.geofex.com/article_folder...s/potscret.htm
How can I generate my LUT values for a 256 pot & have it look like trace 2?!!! (now I'm sure this is embarrasingly simple ....but I now realise that I shouldn't have tried so hard to pull Mary Harbottle during maths lessons)






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