[Coco] [Color Computer] Re: Coco flash cartridge

[James Diffendaffer]

> I have also done a 1st draft of the CPLD (which I've made available on 
> my web page) and it fits within the smaller of the 2 devices - an 
> EPM3032. The limiting factor on the design atm is the pushbutton 
> debounce which really isn't critical IMHO as long as it's a few 
> E-clocks long. So there's a little
> register space left and no doubt plenty of combinatorial logic. 

If you use a counter timing the reset to do the reset internally you
shouldn't need to worry about debounce or the switch since reset only
takes place after the reset is held for a period.  Based on CoCo3 high
speed timing you should be able to use a 24 bit register for the
counter and handle at least 5 seconds.

1.7Mhz = 1,700,000 clocks / sec.
* 5 = 8,500,000 clock ticks
8500000 = $81B320 (Hex)

If the clock reverts to normal on reset WHILE the reset button is held
then it's half that but still requires a 24 bit counter.  If the clock
to the expansion port doesn't run while reset is pressed then using a
counter to time how long reset is held won't work.