From: Jim Brain (brain_at_jbrain.com)
Date: 2008-11-22 05:59:51
I was working on creating a schematic for the WarpSpeed cart, and I am
struggling to figure out how the cart works. My schematic is at:
www.jimbrain.com/incoming/WarpSpeed
I've placed the original pictures I received in the dir as well. Since
the original bare PCB scans were not great, I've asked for someone to
mail me a PCB so I can scan it.
That said, I don't understand the 74LS109 operation. Any thoughts are
appreciated. I don't need to know per se, but I am very curious.
On the reverse engineering, the designer did a bit of obfuscation in
order to make board layout easier. The ROM is a 16kB one, with data
lines and address lines crossed.
64 ROM
A0 A0
A1 A1
A2 A10
A3 A2
A4 A3
A5 A11
A6 A4
A7 A9
A8 A5
A9 A8
A10 A6
A11 A7
A12 A13
A13 A12
D0 D3
D1 D2
D2 D4
D3 D1
D4 D0
D5 D5
D6 D6
D7 D7
Jim
--
Jim Brain, Brain Innovations (X)
brain@jbrain.com
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!
Home: http://www.jbrain.com
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