[Coco] vacant ramblings....

[Steven Hirsch]

On Thu, 11 Jul 2013, Simon Jonassen wrote:

> Hi again...
>
> I have hooked my 1541-II up to an old dos based pc via a passive cable and
> some clever software...
>
> It works a treat, I have transferred disk images to and from the PC no
> problem at all....

Yes, that works - barely.  I have one of those XM1541 interfaces and it is 
very sensitive to the behavior of the parallel port.  As I recall, the 
diodes in the interface had to be Schottky types in order to provide 
sufficient margins.  It used some obscure BC... part number that I never 
heard of before.

> AFAICR the 1541 works with 1 bit serial transfer... (I made an interrupt
> driven load routine many moons ago that utilised the ACK line so as to
> provide 2 bit transfer....)
>
> We have to remember that the 1541 is an intelligent drive with it's own 6502
> processor.... So it can handle alot of the overhead.....

And so it can, but the overall signal managment has some very tight 
requirements.  I'm not saying it's impossible to do with a Coco, but may 
be challenging.  And, what you'd end up with would make DriveWire look 
like an SATA RAID array by comparison.

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