RE: RE: 1541IDE and 1541IDE-S -- and 8250IDE?

From: Jack Rubin (
Date: 2007-12-12 00:17:25

> Hi Jack,
> that's actually a nice idea considering the simplicity of the 
> interface. The problem is the PET memory map First you can 
> simply plug the schematics under the PET CPU, but it needs a 
> chip select line.
> I see those options:
> 1) decode the I/O are $e800-$e80f (other parts of the I/O area
>   have mirrors of the original ICs, so won't work
> 2) use the $9xxx or the $Axxx expansion ROM select line
>   would only work if those are asserted even on write, but I
>   don't think they are
> 3) add an own address decoder (maybe like 2 74ALS688 comparators)
>   to decode an open address space (like $e80x as above, 
>   behind the video RAM, or in the expansion area)
> IMHO the 3rd version is always feasible, but needs an 
> extension of the schematics as it is now

I'm not very capable on the software side but if there was interest, I
could probably prototype a PET version of the hardware interface for
more development, either based on Ruud's original or even better on
Jim's PC board.


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