Famicom PRG pinout different from NES?

[Ziggy587]

Hello. I hate having my first post on a new forum be a "help me" one, but I'm having a problem that I thought was kind of interesting.

So long story short, I'm trying to put Akumajou Dracula (Castlevania 1) onto a Famicom cart but I can't get it to work. I'm using Black Bass 2 as my "donor" cart, as it is a UNROM board. I played the Black Bass 2 cart on my Famicom to confirm that it was in working order.

After I couldn't get it to work I burned Castlevania, and later, Black Bass 2 to an EPROM and tried those and couldn't get them to work either. So then I took the EPROM that I burned Akumajou Dracula onto and put it on a NES UNROM board (Amagon, to be precise) and it worked perfectly fine.

So, this rules out the possibilities of bad ROM, bad burn, not wired correctly, etc. So since I now KNOW that the EPROM works on the NES cart, this leaves me to believe that the Famicom board has a different pinout.

I've searched high and low for the answer, but didn't come up with much. I found this page:

http://wiki.nesdev.com/w/index.php/Kona ... rom_pinout

So I know that the PRG pinout, apparently, isn't always the same. But I was also looking at this:

http://atariusa.com/Famicom_Schematics/ ... matics.png

...that I found from this thread...

http://nesdev.com/bbs/viewtopic.php?t=6950

which shows a Famicom UNROM board having the same PRG pinout as a NES board.


So is it possible that my Black Bass 2 cart has a weird PRG pinout? If I picked up a different UNROM Famicom game, should I expect it to have a normal PRG pinout?

I have a Final Fantays 3 Famicom cart that I put the English translation onto, it had a normal pinout. I recently picked up a Contra, Akumajou Densetsu and Kid Dracula Famicom carts and was planning on putting the English translations on them as well, should I expect them to have normal pinouts as well? Or possibly different since they're Konami games?

Thanks for any help on the matter.

[thefox]

Do you have a multimeter? If so, you can use it to find out the pinout by testing continuity from the cart edge pins to PRG/CHR.

E: Here's the cart edge pinout: http://nesdev.com/rom.txt

[Bregalad]

Nintendo's "custom" pinout is the same on FC and NES carts - even if the cartridge port is completely different.

[BootGod]

Did you do any rewiring on the board? A 128K EPROM is not pin-compatible with NES-UNROM or HVC-UNROM boards. Not sure why it would have worked in the Amagon cart, maybe it didn't try to access the upper half of the ROM. This doc details how to do the rewiring.

Some good news though, your Konami games should give you no trouble at all because Konami boards are EPROM pin-compatible, so you can just drop them right in without any rewiring. As long as you don't happen to get an epoxy board anyways :/

[Ziggy587]

Do you have a multimeter? If so, you can use it to find out the pinout by testing continuity from the cart edge pins to PRG/CHR.

E: Here's the cart edge pinout: http://nesdev.com/rom.txt

Yeah, I guess that's what I'm gonna have to do.

Nintendo's "custom" pinout is the same on FC and NES carts - even if the cartridge port is completely different.

Well like I said, I have a Final Fantasy 3 Famicom cart that I have already put an EPROM on with no problem (same pinout as NES). This Black Bass 2 Famicom cart, however, apparently does not have the same pinout.

Did you do any rewiring on the board? A 128K EPROM is not pin-compatible with NES-UNROM or HVC-UNROM boards. Not sure why it would have worked in the Amagon cart, maybe it didn't try to access the upper half of the ROM. This doc details how to do the rewiring.

I didn't mention, I thought it would be assumed (sorry), but I did in fact rewire it to accommodate the NES pinout. Amagon has a normal NES 28-pin PRG pinout. My EPROM worked on the Amagon cart, but not on the Black Bass 2 cart, even though I wired them exactly the same way.

Some good news though, your Konami games should give you no trouble at all because Konami boards are EPROM pin-compatible, so you can just drop them right in without any rewiring. As long as you don't happen to get an epoxy board anyways :/

That is good news, indeed. I was looking at the Konami pinouts and didn't even notice that it's the same pinout as EPROMs. Thanks for bringing that to my attention!


So as far as this Black Bass 2 cart goes, I guess I'm gonna have to trace all the connections and find out exactly what the pinout is. I'll report back with my findings.

Thanks every one for your help so far!


EDIT: I just checked the pinout of the Black Bass 2 PRG, comparing it to the Famicom cart connector, and it IS correct.

So what could be a possible reason that my EPROM worked on the Amagon cart but not on this Black Bass 2 cart. Is it possible that the ROM doesn't like the CHR RAM or something? But that wouldn't make sense, because I burned Black Bass 2 to an EPROM and couldn't get that to work either (which is what lead me to think it might have a different pinout).

And by the way, I tested the cart before I pulled the Black Bass 2 PRG mask ROM off, and that cart was working.

[blargg]

OK, so the EPROM works on a NES board in a NES, but not on the Famicom board in a Famicom? Could it be that it doesn't work on Famicom, period? If you have a Famicom-to-NES adaptor, try the Famicom cart in the NES, otherwise you can't rule out the Famicom itself. Or maybe you already tried this and I wasn't reading carefully. You mention another Famicom board you've put an EPROM on; can you try the problem case on that Famicom board?

[Ziggy587]

I think I might have just solved the problem (kinda).

Since I just confirmed the pinout, I figured I'd better put the mask ROM back on and make sure this cart still works. It does not work. I went over every inch of this board looking for problems over the past few days, and it appears perfectly fine. At this point I'm pretty sure there's just some voodoo stuff going on.


EDIT: Wow, I totally don't know what to think at all. The Black Bass 2 cart wasn't working at all, just a grey screen. I didn't touch ANYTHING, I just put it back inside the cart shell. Decided to pop it in the Famicom to test again... and now it works! Now I'm positive there's voodoo involved.

OK, so the EPROM works on a NES board in a NES, but not on the Famicom board in a Famicom? Could it be that it doesn't work on Famicom, period? If you have a Famicom-to-NES adaptor, try the Famicom cart in the NES, otherwise you can't rule out the Famicom itself. Or maybe you already tried this and I wasn't reading carefully. You mention another Famicom board you've put an EPROM on; can you try the problem case on that Famicom board?

Well the ROM I'm using is that of a Famicom game, so I would assume it should work on a Famicom. But that being said, I put two different ROMs onto an EPROM and couldn't get them to work on the Black Bass 2 cart either. I can't try it on a different Famicom cart right now because I don't have any that are UNROM. However, since this cart is being just straight up weird, I plan to pick up a different UNROM Famicom cart and try again.

[Ziggy587]

So I figured out EXACTLY what the problem was.

So whenever I put EPROMs on a cart I test out the bare PCB in the console before I put it back in the cart shell. I've done this countless times, and didn't think twice about doing it with Famicom games on a FC system.

So it just clicked for me today. Why I couldn't get the Black Bass cart to work, no matter what I tried, even when I put the mask ROM back on. Then the cart worked mysteriously after I put it back in the cart shell.

When the PCB is out of the cart shell, you're able to push it into the cart slot further than you would be able to if it was inside the cart shell. I found out the hard way that if you do this, the game will not be read. If you're putting a bare Famicom PCB into the cart slot, you cannot push it in all the way, you have to back it out 1/4" and then it'll work.

tl;dr version: The Black Bass cart worked perfectly fine the entire time, I was just pushing it too far into the cart slot. Thought it was pretty funny, thought I would share.

[Banshaku]

I put often cart in my famicom without the case and had no issue. I will try to test it someday if I can reproduce the same issue as you.

[BootGod]

Don't ya just love it when you spend countless hours trying to figure a problem and it turns out to be something so dumb!

I can't push a bare pcb all the way into my front-loader either and have it work.

[blargg]

Yep, I've encountered that. I mean, once you remove it from the cart, you have to be thinking about issues of how far it goes in. I know I did, but the frontloader's slot is really deep, so visually you immediately wonder whether you have to avoid going too far in.