Strikes me $D7xx is the best place for an internal SID modification, being as that is spare in the C128 and actually decoded. No idea who decided $D420 was a good idea, that takes way more in the way of address decoding. Obviously easier in this day of programmable logic devices, but what about a good old 74LS139 for decoding $D400 further? External hardware expansions are likely to use $DExx and $DFxx, including SID cartridges. What I'd really, really, really like to see attached to a C64 is an Ensoniq 5503 DOC. Rainer, you probably know more about this chip than anyone else on this list. It's designed for 6809 bus accesses isn't it? Might be possible to add to a C64 in $DFxx or wherever with minimal extra hardware. Imagine having a 24 bit phase accumulator and 16 bit frequency registers, but instead of sending 12 bits to a DAC, having an 8 bit memory access for every step and outputting the result on a DAC. Then multiplex that phase accumulator up to 32 times for up to 32 channel sound. That's basically what the Ensoniq DOC is. It really is the spiritual successor of SID. Richard -------------------------------------------------- From: "Rainer Buchty" <firstname.lastname@example.org> Sent: Thursday, December 01, 2011 2:51 PM To: <email@example.com> Subject: Re: Additional SIDs > On Wed, 30 Nov 2011, Groepaz wrote: > >> actually most "older software" uses DE00 or DF00, ie whats available at >> the cartridge port. D700 i havent seen in the wild, i think =) > > Although DE00 is a particularly bad choice for SIDs, as MIDI interfaces > like to reside here (DE04-DE07). > > Rainer > > > Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2011-12-01 18:00:25
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