From: Marko Mäkelä (Marko.Makela_at_HUT.FI)
Date: 2002-04-08 08:33:44
On Sun, 7 Apr 2002, Richard Atkinson wrote: > The "hardware modification" you speak of can be done entirely externally - > it's just a lead going between the monitor connector (and SYNC pin > thereof) to the cassette connector (IIRC). And the VIA's own timers can > then be used once synchronisation is achieved. Yes, similar to the raster interrupts on the VIC-20. You only need to read the raster beam's position in order to determine when to start the timer. I wonder if the position could be determined by reading open address space (like $de00-$dfff on a C64). I wonder if the same could be done on the ZX Spectrum. That'd probably break all Spectrum emulators. :-) > I haven't got a reference handy of which lines (if any) the cassette > shares with the PSG, but it sounds like simple power supply noise > issues to me. Or adjacent signal lines interfering each other. I remember that the Soundblaster card installed to a 286 PC of my friend made quite some noise when the hard disk was accessed. Marko Message was sent through the cbm-hackers mailing list
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