Posted By
crock
on 2016-02-04
19:03:56
 |  Re: Blank cartridge boards
On a normal 264 cart, the /OE on the ROM's is attached to pin B (C1 low) and pin 6 (C1 high) respectively, meaning the cartridge is made addressable by accessing $fdd2. C2 low and C2 high are also available on pins 7 & 8 respectively, but not used on any 264 cart I have ever seen, which is made addressable by accessing $fdd3.
The easy addition would be jumpers to map the ROM's to C1 or C2. The deluxe option would be the ability to take a pair of 32k x 8 EPROMS addressable as bank 2 and 3, meaning 64k of ROM on the cart.
Not sure you could do this without additional gates on the board though, as a combination of C1 and C2 would need to drive A14 and /OE.
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