> > > On 29 Apr 94 11:39:41 GMT, Simon Cooke said: > > > The SAM's own processor doesn't know a thing -- it's quite nicely > > kept busy with a well placed 0v on the BUSRQ line :) > > I haven't had the time to study the specs in detail, but it > seems to me that suspening the Z80B is a terrible waste of > resources. What about letting the Z80X use the Z80B as a > co-processor? Fix it up with a separate ram-block, or a way > to pass PC to it, and then enable it with an I/O command? > > Any thoughts?
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? Plus, with the current design, you can plug in *any* existing SAM Coupe' software and speed it up -- it's totally SAM Compatible (although we may be looking into putting extra wait states in when the disc drives are used). 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]
