Homebrew STG card

[Paul Corner <Paul.Corner-at-tesco.net>]

Hi Ray, Matt

I've spent a few hours just doing some rough layouts - checking to see if
everything will fit.

Matt asked :
> I'd like to add two 8254 ICs to provide high frequency stepper outputs as
> well.

Would you want the timer outputs brought out to a connector. Or would an
interrupt need to be generated from at least one timer ? - Subject to space, a
small scratch pad area with access to the IRQ and timer outputs could be
included.
I have a target length of 160mm for this card, 200mm is the most I really want
to go.

Ray suggested :
> I'd like to see some socketed chips or other protection for some of the
> critical i/o. 
> I'd also like to see more than 24 i/o points.

I was planning on using sockets for all the chips - those PLCC pakages are a
real *** to rework, and socketing them does make life easier.
How does two 8255 PLCC chips sound - they won't take up much more space than a
40 pin DIL package.
Your comment about Mazak blowing a board is just the reason why I want to stick
to 'off the shelf' components. FPGA's are useful - but I have reservations
about their use. The RAM based FPGA's are fine, but if expensive programmers
are required, then I will shy away from them.

Regards, Paul.