Re: Several answers

From: Andre Fachat (
Date: 1998-03-27 11:27:48 wrote:
> Hallo Andre,
> > I once made an IEEE488 cartridge for the Atari ST ROM port, without
> > tapping R/W. reading from a block of 256 addresses is outputting data
> > on the address lines :-)
> Smart, but costly. But this triggered my mind to produce the following idea
> but based on your original concept. Replace the 6510 by a board with the
> 6510, a 74LS610/2, buffers, some glue logic and a bus to connect even more
> hardware. In this way you can use your C64 as you use your CS/65 a pod for
> your 1541. One question remains: how do you handle the clock signal? Is it
> possible to use the 1541 wih a "processor" which is running asynchrone with
> the onboard 16MHz. clock.

Hm. This idea is quite nice actually. Why didn't I have it :-)
I think the 6510 with 2 MHz (because of the MMU 74ls610 delay you 
need a faster CPU - it puts the addresses on the bus earlier, even 
if clocked with 1Mhz) is not available, and I would have to build
the CPU port myself. And then you can also take 65sc816 or such a beast
for it - although the MMU solution is _much_ more elegant :-)

> > .... Remember, the PET has _no_ NMI source.
> ?????? What do you mena with this?

That was a comment on something I don't remember...

The NMI line of the CPU is only connected to the expansion port of the 
8032 (see your schematics on funet - BTW could you please upload a version
where the drawing color is not transparent? Netscape prints transparent
on white -> completely white :-( The 3008 schematics is ok.)


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Andre Fachat, Institute of physics, Technische Universitšt Chemnitz, FRG

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