Can I use two 27c512 chips on a donor cart that has 64k for PRG and 32k for CHR without rewiring? I'm making a cart that has 64k for PRG and CHR and using 27c512 eproms. All donor carts use the same mapper, just some have less ROM size.
Thanks
What mapper is this? And what's the donor cart?
It's possible that the chips will work without rewiring, but if the original CHR-ROM was smaller than the new chip, it might be necessary to connect some address lines from the mapper to it.
tokumaru wrote:
What mapper is this? And what's the donor cart?
It's possible that the chips will work without rewiring, but if the original CHR-ROM was smaller than the new chip, it might be necessary to connect some address lines from the mapper to it.
Mapper 11, Raid 2020 for example
http://bootgod.dyndns.org:7777/profile.php?id=735
I should have figured it was mapper 11, considering the ROM sizes. Since these aren't licensed games, we con forget about the pinouts of Nintendo Mask ROMs. I imagine that the chances of these chips having the same pinouts as EPROMs are fairly high.
If I were you, I'd try to replace the chips without rewiring anything. If the programs runs but the graphics are scrambled I'd check the highest CHR address lines, which might not be connected from the mapper to the CHR chip.