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 Post subject: [MD/Gen] Multi EPROMs
PostPosted: Sun Jul 27, 2014 2:10 am 
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Joined: Fri Jul 04, 2014 2:34 pm
Posts: 296
Location: Germany
Hello,
I was wondering if it is possible to use more than one EPROM (namely 27c322) with the use of a 74LS139. If it is, how would it be connected? Pin 1 goes to /OE obviously but would I need to connect Pin 2 and 3 to A21/A22 or somewhere else? Help is appreciated, if someone knows how to do this.
I'm planning to put the BadApple Demo (which is 8MB btw) on a cart just to test how it works.


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PostPosted: Sun Jul 27, 2014 12:36 pm 
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Joined: Sun Apr 13, 2008 11:12 am
Posts: 6529
Location: Seattle
You should probably ask on a forum that knows more about the megadrive... my best guess is that you'll hook up 68000.A22 to 74139.A, 68000.A23 to 74139.B, 68000./AS to 74139./G, and 74139./Y0 and /Y1 to the two ROM's /CE pins.


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PostPosted: Wed Sep 03, 2014 3:43 am 
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Joined: Wed Aug 26, 2009 8:28 am
Posts: 71
Have been wondering the same thing Ice Man. A 12MB Ultimate Mortal Kombat Trilogy reproduction would be fun to wire up.


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PostPosted: Thu Sep 04, 2014 2:01 am 
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Joined: Wed Jul 22, 2009 8:53 am
Posts: 119
Isn't there anything interesting on http://nintendoallstars.w.interia.pl/romlab/romlab.htm ?? Check Sega Mega Drive/Genesis section and you can find this:
http://nintendoallstars.w.interia.pl/ro ... 4cart1.jpg
http://nintendoallstars.w.interia.pl/ro ... 4cart2.jpg


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