Re: A new pseudo-disk for Apple 2.

["Alex Freed" <alexf@mirrow.com>]

"Linards Ticmanis" <ticmanis@gmx.de> wrote in message
news:44c2b95a$0$24891$9b4e6d93@newsread4.arcor-online.net...
> I don't have the data sheet for NMOS 6502 around.. what exactly is the
> effect when you don't assert READY? The processor will fetch a byte but
> will still stay stuck at the instruction it's at?

Yes, that's pretty much it.

6502 is/was not static so you could not disable the clock for a long time.
The idea od a READY signal is that if the
data is not ready, the CPU should waste a cycle and try again. This was the
mechanism used by the z80 SoftCard.
z80 does a memory refresh cycle on every insruction fetch. So z80 had "DMA"
access to the bus all the time except
during these memory refresh intervals when the 6502 was given a clock cycle
but RDY was not asserted. So the
1 uS cycle was "wasted" but the 6502 registers were preserved.

-Alex.