[MD/Gen] Multi EPROMs

Discussion of development of software for any "obsolete" computer or video game system. See the WSdev wiki and ObscureDev wiki for more information on certain platforms.
Post Reply
Ice Man
Posts: 547
Joined: Fri Jul 04, 2014 2:34 pm

[MD/Gen] Multi EPROMs

Post by Ice Man »

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.
lidnariq
Posts: 11432
Joined: Sun Apr 13, 2008 11:12 am

Re: [MD/Gen] Multi EPROMs

Post by lidnariq »

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.
darknezz19
Posts: 73
Joined: Wed Aug 26, 2009 8:28 am

Re: [MD/Gen] Multi EPROMs

Post by darknezz19 »

Have been wondering the same thing Ice Man. A 12MB Ultimate Mortal Kombat Trilogy reproduction would be fun to wire up.
User avatar
MaarioS
Posts: 149
Joined: Wed Jul 22, 2009 8:53 am

Re: [MD/Gen] Multi EPROMs

Post by MaarioS »

Post Reply