SNES Controller IC Pinout

Kurt_ · Post by **Kurt_** » Thu May 04, 2006 7:14 pm

Thanks guys. One more question.

Is this any easier than wiring the controller by the book? As I'm sure some of you are aware it's not working well at all for me. This is a nice alternative, but then I'd have to undo waht I did with the 4021's.

shmagoogin77 · Post by **shmagoogin77** » Thu May 04, 2006 7:22 pm

i tried soldering directly to the snes controller chip but it just frustrated me so i decided to do it the way in the book
just ordered my 4021 decoder chips and resistors from mouser

Turbo Tax 1.0 · Post by **Turbo Tax 1.0** » Thu May 04, 2006 7:54 pm

i think its easier to do but make sure to use flux and cover your work in hotglue once you give it a quick test

shmagoogin77 · Post by **shmagoogin77** » Thu May 04, 2006 8:28 pm

im not that good at soldering

Kurt_ · Post by **Kurt_** » Fri May 05, 2006 12:14 pm

Well I'll try it. I'll let you know how it works out.

joevennix · Post by **joevennix** » Fri May 05, 2006 3:08 pm

Someone should make a breakout board for this IC out of breadboard and a few header pins, by soldering a short wire from each lead on the IC to a header on the outside of the board. Like this:

This should make it easier to interface with.

Post by **marshallh** » Fri May 05, 2006 3:33 pm

Search Digikey for "Surfboards"

That's exactly what you're talking about.

joevennix · Post by **joevennix** » Fri May 05, 2006 4:32 pm

I always knew them as "Breakout boards," not surfboards. That probably explains why they never showed up in my searches. Oh well, my way works the same, just requires some soldering skill

MM007 · Post by **MM007** » Sat May 06, 2006 9:29 pm

The IC may be different...but I wouldn't be surprised if something similar applied to the NES. It's the same basic wire conficuration and setup, simply with 8 buttons instead of 12. Heck, it may be possible to use an SNES chip in an NES controller...

*Considers a "parted" or "button" connector for use in NES and SNES controller ports, and maybe a switch between NES w/Turbo and SNES configuration or something...*

Anyone have a logic gate diagram of the IC?

Edit:
Apparently, the NES IC is a 4021 CMOS 8-bit Shift register, and the SNES uses a 16-bit Shift Register, with 12 enabled.

It may be possible to make 4 extra buttons on the SNES...assuming the hardware supported it, and the game was programme)d to use them.

Here is a like to a page with the NES's control chip's spreadsheet, which contains a logic gate schematic. Still looking for the 16-bit one.
http://www.standardics.philips.com/prod ... ters/4021/

Here is a simple pin-out with more official names for the 8-bit version, still looking for 16-bit version.

http://www.xs4all.nl/~ganswijk/chipdir/giicm/4021.txt

Here's even more data, and the NES controller chip's price, and the chance to buy it... $0.26 US.
http://focus.ti.com/docs/military/catal ... ionId=8921

Anyone who knows the 16-bit equivalent chip the SNES uses to the NES's 4021 is humbly asked to divulge the information. This has got me curious. ^^

Edit 2: Apparently, the SNES uses two 4021 cascaded together into one chip.

http://cgfm2.emuviews.com/txt/snestech.txt

Also, adding four buttons, given the SNES configuration is impossible...but a NES/SNES hybrid controller IS possible.

shmagoogin77 · Post by **shmagoogin77** » Sun May 07, 2006 6:03 pm

nice research

MM007 · Post by **MM007** » Sun May 07, 2006 6:39 pm

There's more. ^^

According to:

http://www.neshq.com/hardmods/snes_to_n ... roller.txt

It is possible to use the SNES controllers on the NES.

It gives the wires that correspond to each connector on the plug, the plug numbering, and other tips, including what buttons on an SNES controller work on an NES.

When using the SNES controller to play NES games, the D-pad, Start and Select
buttons function as you would expect. SNES button Y is equivalent to NES
button B, and SNES button B is equivalent to NES button A. The other buttons
(A, X, L and R) have no function on the NES.

This sounds funky, but SNES Y and B map physically to NES B and A anyway. and it is possible to use a timer IC and two more gates to make the SNES X and A buttons act as NES B Turbo and A Turbo when in NES mode by attacking a timer's clock and the button pressed to the chip. This could all be toggled by a switch, using the power for the timer IC and the gates.

If you just want an SNES controller for your NES and no turbo, it'll work fine on it's own...if you don't screw up the rewiring of the connector connector. The SNES controller is fully reverse compatible with the NES, though I can't guarrantee forward compatibility.

While rewiring the connector may be fun, this also means that an SNES/NES/Famicom combo system is plausible, using the same internal controller design(modded to offer turbo in NES/Famicom mode, perhaps), standard SNES controllers, and a player 2 NES controller port, split right off of the SNES port, for a Zapper or Power Pad. It may also be possible to map Start and Select through R and L in NES mode, though they wouldn't be directly jumpered. A four-inverter 74-series chip could do the trick, toggled on and off by the main power.

Before I make any sort of schematic for this, I need to know if the SNES chip registers a button press on a LOW, or on a HIGH. Can anyone tell me which is the case?

blackbox_dev · Post by **blackbox_dev** » Sun May 07, 2006 6:56 pm

Wikified it.

Post by **Gamelver** » Sun May 07, 2006 7:16 pm

oh yeah, I remember someone (gannon, perhaps) mentioning this before....

nice find, though, MM007

. and I think that the SNES registers a button press on a LOW....I know for sure that when you push the button down, it causes the previously open switch between ground and the pin to have some resistance across it...so...wouldn't that mean it'd have to be at some higher voltage, and then brought down because of the resistance?

if not, then I blame a lack of sleep for my ignorance! if I was right...then, well, I told you so

.

timmeh87 · Post by **timmeh87** » Thu May 11, 2006 8:35 pm

you should probably have the 200 ohm resistors. i think the purpose is to control the current flow through the chip. theoretically it could eventually fry because its going to have 200 times more current running through it than it was designed for (or something of that nature)

anyways, at 4 cents a piece off digikey, i really dont see why you wouldnt just put them there.

Kurt_ · Post by **Kurt_** » Fri May 12, 2006 5:58 am

And the capacitor? Decoupling capacitor I'd assume.

Anyways I can say that the brown wire can NOT attatch to pin 10 and work. I mighta just messed something up with that, but I'm pretty sure it can't.