> > Yeah! I am still wondering WHAT's so elegant about it :) I guess if > > I keep these postings coming, I'll never know. :) > > Ooooh.. well... > > Let's put it this way; it uses a 0.5Mb memory mirror with controlled > wait states and read-writes, and has a 20Mhz processor in it. > Basically, the Z84C0020 (20 Mhz z80, now called by me the Z80X), acts > on decision control logic: > > If reading from internal RAM, read only from mirror mem, and ignore [...]
This sounds very clever, a little bit like a CPU cache in fact... Right? > > If doing an I/O and control port is set to do so, ASIC WAITs will be > ignored. This is only in as a test feature -- both Bruce and myself > don't know if it'll work if I ignore the WAITs during I/O. > >From my own experiences in the lab here, WAITs for I/O are vital, but I'm no expert... > We were thinking of using a FIFO memory so that ports and memory > could be accessed that way, giving even more increased speed, but > decided against it. > How do you mean, exactly? > Current hardware details: > > Memory: 512kb > Processor: Z84C0020 > Logic: 3 octal latches *so far*, various gating and switching logic. > Will have a thru' connector, and sockets on the board for an > expansion to turn it into the SAM equivalent of a MultiFACE. > Presumbly snapshotting one lot of 512k in the other? > SAMBus will have to be connected *into* the thru'connector. Probably. > I remember trying to get all my Speccy add-ons in the right order, ie one that works! The NMI line for the Multiface was quietly ignored by some things, which was a real pain. > _____________________________________________________________ > PORT 238:| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0| > ------------------------------------------------------------- > |MFACE | CLOCK |I/OWAIT| ASICW | Mirror bank selection | > ------------------------------------------------------------- Of course, you could put other things besides a multiface thingy in there, just plug in the ROM you want, really... > > *grins* don't say I never tell you anything. > > > What about persuading him to adapt your *elegant* accelrator into > > a dream-computer, with pipelining and co-prosessors for EVERYTHING? > > Erm... problem: we want it to not cost too much money, and be an add- > on for the SAM. Any price estimates yet? Hopefully the 512k memory won't be as much as SAMCo (used to) & West Coast charge, which is crazy cash. > Si oops. Can't comment any more, as I've got a lecture to go it in about -2 minutes. Bye Nige
