From: Nicolas Welte; address is valid for replies (Re:) only! (welte_spam_at_freenet.de)
Date: 2002-09-01 00:32:21
Hallo Ruud,
> > Rossmöller 8MHz Z80 accellerator module for the C128,
some news about this: Of course it's GAL chip is read protected, so it can't
be cloned the easy way.
I also made my first own GAL for the PETRAM expansion. Everything works nicely
so far, now my 2001 has 32kB of RAM and 64kB of ROM :-) I put some pictures
onto my projects page.
> The moment the z80 initializes a transfer, a circuit puts the Z80 in
> waitstate and waits for the positive edge of PHI2. The negative edge
> releases the Z80 again. The 573 makes sure that the read data is still
> available for the Z80.
Hmm. I think the C128 already latches the data from the Z80 anyway, and the
waitstate idea is exactly what is used on the Rossmöller board. I saw that it
connects to the waitstate input on the Z80. I really must draw a schematic of
the little board.
Nicolas
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