[Coco] Proto CoCo

[jdaggett at gate.net]

On 28 Aug 2006 at 21:03, Phill Harvey-Smith wrote:

> jdaggett at gate.net wrote:
> > On 28 Aug 2006 at 14:34, Roger Merchberger wrote:
> > 
> >> That's one of the main things that's been stopping me from a pet project I
> >> started about 5 years ago... The other thing was drilling *all* those
> >> holes for a fair amount of TTL to do the buffering/latching/address
> >> decoding for.
> 
> You could of course use a CPLD for some of this, I tend to use Xilinx 
> XC9572s for this sort of thing, plus you can do address decoding & 
> latching inside them also :)
> 
*******************

9572/9572XL would be nice. The 84 pin PLCC package would be needed at minimum.  


> > Who drills holes?????
> 
> Well you would have to for some things on the CoCo, as the expansion 
> connector is double sided, so some signals will be on the wrong side of 
> the board :)
>

Any holes would be done by the PCB manufacturer and would be plated through holes. 

> > SMT is the way to go!!!!
> 
> Possibly, though through hole does have the advantage that it can be 
> socketed, and so if you screw up your board (as I have done a couple of 
> times :) )then it's easy to re-use components :)
> 
> Also some of the old chips that people are playing with are only 
> available in through hole :(
> 
That maybe true. But large amounts of dip packages would mean the board would have to 
grow in length. Width is somewhat fixed.