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 - Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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