> > Yeah loads of them -- about 8 months ago. It wouldn't work, due to > > the way I have to keep copying stuff to and from the memory. Also, > > it'd mean stealing about 1/3rd of the Z80X's clock cycles to run the > > Z80B -- the Z80B would run at full speed (with ASIC contention), the > > Z80X at about 12Mhz, with lots of contention that wasn't there > > before. Also, it plays havoc with I/O -- which processor wants memory > > paging and where? > > Well, if the Z80B only could address ONE 64K 'bank' of memory (eg. bank 0-1 > plus eg. the current screen, ie. it addresses those banks only, no matter > what else is paged in, and what the Z80X is using, ie. the Z80B has it's > paging ports disabled :)), you could choose whether to use those pages > as Z80B or Z80X memory, and when wanting to use the Z80B, you just do a > i/o which performs a reset on the Z80B (assuming the code starts at > adr. 0).
Hmmmm... nawww... rigging the two together in tandem would be a bitch. Besides, think carefully: the Z80x uses the *same* address bus as the Z80b... result: screwups. If we had direct access to the memory via the expansion bus, then maybe we could do it, but the ASIC is in the way... So we have to go via paging, and the ASIC has to know which is paged in where at any time. TRUST ME. I've looked at the possibility of slaving the z80b lots of times when working on this -- it just ain't feasible. > > Plus, with the current design, you can plug in *any* existing SAM > > Coupe' software and speed it up -- it's totally SAM Compatible > > Yeah, well...how about the time-critical stuff, like borderscrolls, > sample-players (that does not use line-int) :) Hmmm...no, just > kidding. I'll be delighted to be able to speed things up! *grins* welll..... I've put in the option to switch to a 6Mhz clock and use the ASIC waits, so it'll work the same as a SAM in that configuration. Si +------------------INTERNET: [EMAIL PROTECTED] | "You know... you can tell someone's vain when they quote themselves | | in their own .sig file..." -- Simon Cooke | +--------------------JANET: [EMAIL PROTECTED]
