Wiring Issues: 32Pin Eprom, in 28 Pin CHR slot on SNROM

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Funky Charms

Wiring Issues: 32Pin Eprom, in 28 Pin CHR slot on SNROM

Post by Funky Charms »

I am having a difficult time figuring this one out. Any information you have would help alot. I have compared and compared until I am blue in the face, and I can not figure this one out. Every SNROM board that I have found that contains a battery, Uses a 28 pin CHR Slot, there is not even a pinhole for Pins 1/2 and 31/32. I can not find anywhere a 28 Pin 1meg eprom anywhere or I would do that. Any Ideas on how I could wire a 32 pin eprom with this? I looked in the doc's on here, eprom pinouts, eprom conversion's ect ect, but they do not contain this. Thanks Alot!
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Memblers
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Post by Memblers »

SNROM doesn't use a ROM for CHR, it uses an 8kbyte RAM. Should say "CHR-RAM" right there on the board. So if it's SNROM you're going for, you only need to replace the PRG-ROM.

But, it's true that Nintendo's 128kbyte ROMs are 28-pin, while 128kB EPROMs are 32-pin. Doesn't affect SNROM though.
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Post by Guest »

Memblers wrote:SNROM doesn't use a ROM for CHR, it uses an 8kbyte RAM. Should say "CHR-RAM" right there on the board. So if it's SNROM you're going for, you only need to replace the PRG-ROM.

But, it's true that Nintendo's 128kbyte ROMs are 28-pin, while 128kB EPROMs are 32-pin. Doesn't affect SNROM though.
Ahh okie. Are there any SLROM boards with batterys then? The game im trying require's MMC1 (according to cajones), battery, and it splits into PRG and CHR
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Post by Memblers »

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Post by Guest »

Lol thanks, I didnt even know there was a SKROM. Looking at the doc's here, http://www.nesdev.com/NES%20EPROM%20Conversions.txt, SKROM is not even listed....is it wired the same as ... ? Thanks
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Post by Memblers »

Heh, yeah I keep neglecting to add those docs to the site.

You should be able to follow the directions for UNROM, same for both chips.

But if the chips sit close together on the board, it might not fit. Because of the 28-32 pin difference.
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Post by Guest »

Memblers wrote:Heh, yeah I keep neglecting to add those docs to the site.

You should be able to follow the directions for UNROM, same for both chips.

But if the chips sit close together on the board, it might not fit. Because of the 28-32 pin difference.

So Follow UNROM wiring for the SKROM board?
Funky Charms

Post by Funky Charms »

Memblers wrote:Heh, yeah I keep neglecting to add those docs to the site.

You should be able to follow the directions for UNROM, same for both chips.

But if the chips sit close together on the board, it might not fit. Because of the 28-32 pin difference.
Ok, I tried it like the unrom listed in the doc's, and I got a bunch of garbage on the screen, but I could hear the music ect ect...I tried 2 boards, and several burns of the chips. I also got the same results as below, which are the one's that I use personally on another game.


Bend up pins 1, 2, 24, 31 and 32
Solder pin 1 to pins 30, 31 and 32
Solder pin 2 to hole 24
Solder pin 24 to pin 16
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Post by Memblers »

Hmm.. I looked again at the the NES ROM Pinouts doc (http://nesdev.com/NES%20ROM%20Pinouts.txt) and just noticed the 128kB CHR-ROM is 32-pins. So I guess the CHR socket is 32 pins on SKROM? Sorry, I didn't know about that. I figured it was the same type as the PRG. :?

The directions for the SLROM CHR socket should work, I think.
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Post by Memblers »

Off-topic posts deleted. ::sigh::
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