Re: [stella] baubles.bin v0.001, was Re: Stella Photoshop colorpalette and question

Subject: Re: [stella] baubles.bin v0.001, was Re: Stella Photoshop colorpalette and question
From: Chris Wilkson <ecwilkso@xxxxxxx>
Date: Mon, 10 Sep 2001 12:49:25 -0400 (EDT)
On Sun, 9 Sep 2001, B. Watson wrote:

> I've now got a cart board (made of a dead Pitfall cart) that I can plug a 27256

> The thing looks awful, it's a patchwork of jumper wires and hot glue, I think
> I'll call it FrankenCart...

Hmmm...that's what I called my first attempt.  Must be a common name.  :)

> For the bank-switched version... I don't know the standard way to do this, but
> I have a few 13-input AND gate ICs, and lots of invertors, so I should be able
> to wire all the address lines to the inputs of the AND gate (and the unused
> input to Vcc), and invert the appropriate ones, until I have a gate that will
> trigger when the magic memory location is accessed. Then I need a what, a
> flip-flop or something, to control the A12 line of the chip?

This is basically correct.  You'll need some form of register (it doesn't have
to be a flipflop).  You'll also find (maybe) that you'll need a glitch filter
for the output of your detector, to avoid false switches caused by asynchronous
(reletive to each other) address line transitions.  This will be a parts
intensive board, even for dev purposes.  You might want to consider using
programmable logic, if you're able.  It will simplify things a lot.

-Chris



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