Re: [stella] 8K Cart question

Subject: Re: [stella] 8K Cart question
From: Chad Schell <gamer@xxxxxxxxxxx>
Date: Fri, 03 Nov 2000 18:18:05 -0800

Thanks for the reply. I'm doing this for educational purposes at the moment. (VHDL tinkering.)

I've already thrown together a quick test version, and sure enough, it's glitchy. In fact it was those glitches that brought me to this list. I was pretty sure "slow" transitions on the address bus were the problem, but I wanted to make sure I was understanding the basic bankswitch method first.

Any good suggestions on protecting against glitches? Preferably without using clocked logic.


At 06:25 PM 11/3/2000, you wrote:
In message <>, Chad Schell w
>I have a quick sanity check I'd like to ask the list concerning building 8K
>carts using the F8 bankswitching scheme.

Hi Chad,

Hrm...your setup might work.  Be sure to do some kind of glitch filtering...
those address lines are nasty!  What I mean by this is best shown by example:

Say I have a 2 bit bus (no pun intended!), which I'm watching for "01".  If
the bus changes from "00" to "11", and bit 0 changes first, I'll see "01" for
an instant.  Just be aware that the address transitions aren't instantaneous.

One other thing:  if you're doing this for a one-off project that's good.
But if you're trying to do something large scale, you're probably better
off just ordering boards from someone else.  8K and 16K boards are readily
available...from me, for instance.  (they also work with 2K and 4K images)


Good luck!

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