Cartridge Slot

Hi,

I am working on a multi platform gaming system. For the NES part i buy (some years ago) A31721-ND slot.I read on this forum that i can't work because of a pitch problem but it seems that some people use it (here).

Some one as the right answer ?

Thks

The "best" answer we've found is two card-edge connectors (one 30-34 pin, one 34 pin), with a slot cut out of the end, facing each other, spaced such that the "metric inch" (of the actual connector) vs "real inch" (of purchasable card-edge sockets) difference is consumed in the unused EXP pins.

Do you have a P/N of this kind of slot ?

You says that some pins are unused, it's really unuse or just useless ?

http://wiki.nesdev.com/w/index.php/Cartridge_connector

The EXPx pins only go to the expansion port on the bottom of the NES. A very small number of PCBs connect anything to them at all, such as the MMC5 boards.

The US toploading NES doesn't include metal contacts for most of the EXP pins.

Ok thks. So i need to buy new parts and rewrite my pcb schematic

What do the MMC5 boards connect to the expansion pins?

oh.. so if i don't map this pin, some game will not work ? if yes i need all pin so the 2 slot method will not work ?

No, no games require anything from the expansion ports. If anything is ever connected to them, it was unused and not required by the game.

EXP5: for MMC5 carts with PRG RAM, connected to PRG RAM /OE, pulled down on-cart with a resistor. I have absolutely no idea why they thought this was useful or interesting.
EXP6: ultimately connected to MMC5 audio, if all audio mixing parts (R1, R2, R4, R9, C2, C3) are populated.

[quote="lidnariq"
EXP6: ultimately connected to MMC5 audio, if all audio mixing parts (R1, R2, R4, R9, C2, C3) are populated.[/quote]

It happen on some cartridge ?

No, no US/EU MMC5 cartridges were ever shipped with the audio mixing hardware populated. Correspondingly, no US/EU MMC5 games use the audio generation hardware.

Some people may have populated the parts and put on EEPROMs to play music and/or homebrew or romhacks, but that's it.

ok cool, it's fine for me. But i have to found small slot. Do you have a website and a P/N that you already test ?

I've installed an A31721-ND part on my NES (bent the leads and sorta made it into a top-loader), and have been using that without any notable problems. With PCBs of my own design, and Game Genies, I've found that I can make it short if I purposely slide it to one side (I haven't tried this a whole lot with Nintendo's carts, I think they shorted also but it was fewer pins shorted, though PCBs will vary). Sliding the other way is fine. 99% of the time, when I put a cart in like normal, it just works. Surprisingly.

If you really need a perfect pitch connector, you can get one from a Game Genie. From what I've heard (haven't seen it in person myself), NES clones, and that "Blinking Light Win" connector all use that same A31721-ND (or similar) part. The concerns are understandable, but maybe a bit overblown.

And simultaneously integrate the Game Genie functionality into the console. That would be cool.

It would be, but the Game Genie does have some bugs. It causes the intro to be skipped on a lot of games because it doesn't wait for start to be released, and it messes up the sound in maybe most Capcom games. I actually made a build of ROM that fixes those bugs, if anyone wants it. I haven't released it because I haven't yet tested blargg's bootloader that I put into it, not sure if I can duplicate his setup, so it's been put off until I write some PC-side software for it.

Does it also restore the pulse sweep registers to power-on default, so that it doesn't do the weird thing with e.g. Megaman mumblemumble ?
What's there to test? The original 256-byte bootloader schema seemed awfully bulletproof.

Yeah, I fixed that. I also changed $0D in the palette to $0F, though that hardly seems to affect anyone. I also shortened the time that it waits after it initializes the chip, I'm not sure why it waits so long, like 10 frames, it doesn't even touch the ASIC again until you press start (or rather, release start, in this version).



The untested part is how best to determine whether to run the bootloader (which has no time-out or way to escape), or the Game Genie. Initially I wanted to use the break condition (transmit state opposite of idle), but I found out that's not universally supported among USB adapters. Using the CTS line would be ideal, but I'm having trouble sourcing cheap USB adapters that break out the flow control signals. I found one that I like, but I don't know where to get them now.. suppliers that sold it before now just have ones that only have TX and RX. Plus I know at least a small number of people have built adapters using NES controller cables, that don't have wiring for the extra signals. So the method I have in there now, which is completely untested, sets OUT0 high (so it repeatedly reads the A button if there's a controller) and waits for some time while checking D0 to see if it's state ever changes. When that times out, it runs the usual Game Genie program. So in theory, the PC-side program when you trigger an upload, would continually send a $55 byte or something and hope the NES sees the bits coming in, then would send the actual bootload program after it hears something back from the NES (was hoping the bootloader's CRC error response is enough). Or the user can press the A button during that time and hose everything up, but that's a small trade-off. There very little memory left to play with, I optimized the original program to barely fit all that in, and any additional optimizations will be hard-won.

I don't want tu use game genie so i need to use my own slot. But i'm lost, one says that A31721-ND works other say snot

What I originally meant by bringing the Game Genie into this, is that you could remove the connector from the GG board and use it alone. It's 2.5mm pitch, while everything else is 2.54mm.

You said you bought one of the Digikey ones a while back, you can try it yourself by plugging a cart into it and use a multimeter to check to see if any adjacent pins shorted or not. In my experience, when it does short, it was always the pins nearest to the lockout chip.

The Digikey one is surprisingly safe. Everything from those cheap Yobo clones, to those ridiculously high-end $400-$500 NES clones are using 2.54mm pitch connectors.

edit: It does seem weird to me that I can make it short if I try, but during normal use, it seems to work fine. So the mixed-messages are understandable.

Are these systems using a 2.54 mm pitch slot with or without the .7 mm cut out of the expansion area? The .7 mm compensates for much of the cumulative difference from one side to another, allowing PRG and CHR+CIC to be aligned separately. In theory, it can make shorting more difficult.

I doubt it, for production if they were going to customize the body of the connector like that, I wouldn't think there would be much advantage to doing that vs just making it 2.5mm all around. I should note too, that I don't have any of these clone systems myself, I'm just going by what I've heard.

I've thought about getting a quote from a connector manufacturer about getting some made for some of the project ideas I've had, but I seriously doubt it would be economical without getting into some impossibly huge quantities.

Byuu tried to ask around for SNES expansion slot connectors and couldn't even get anyone to give him a quote. The only person I know of that's ever been successful with something like that is the guy that made the Retrode, though now that I say that, I'm not even 100% sure he actually did get a 2.5mm connector made, maybe he used a 2.54mm one. I know TE Connectivity makes a 2.54mm one the right size for SNES (overall slot size-wise, obviously it's still iffy getting the pitch lined up right, but you can do it if you're reeeeeally careful, and if you ignore the expansion pins, the normal carts line up pretty easily).