On Tuesday 30 June 2015, 11:41:54 Marko Mäkelä <msmakela@gmail.com> wrote: > What you could do is that you could improve the keyboard scanning. Some > 20 years ago, I made some experiments on the C128. I found that making > the outputs to all-1 between each scan iteration would reduce the > shadowing. > > Another idea that you could do is to read the matrix from ‘both > directions’ (first driving the columns and reading the rows, then > driving the rows and reading the columns). Remember that you have a > dedicated CPU for the keyboard, and not just a few hundred 6502 clock > cycles in a timer interrupt. > > Also, did you check the article in the C=Hacking Issue #6 about keyboard > scanning: http://codebase64.org/doku.php?id=magazines:chacking6 i made some more tests a while ago when trying to improve VICE a bit, see here: https://sourceforge.net/p/vice-emu/code/HEAD/tree/testprogs/CIA/ciaports/ (also contains more tech babble in the readme :)) -- http://www.hitmen-console.org http://magicdisk.untergrund.net http://www.pokefinder.org http://ar.pokefinder.org Egal ob sich Elefanten lieben oder bekaempfen, Gras wird immer zertrampelt. <Indisches Sprichwort> Message was sent through the cbm-hackers mailing listReceived on 2015-06-30 09:01:19
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