SNES controllers on Famicom

[saimen10]

Hello,

I have unplugged the standard Famicom controllers from the mainboard and directly solderd SNES controllers to controller port 1 and controller port 2.

SNES controller for player 1 works fine. Up, down, left, right, start, select, A (mapped to B on SNES controller) and B (mapped to Y on SNES contoller).

But the SNES controller for player 2 does not work as expected. It produces permanent, automatically, incorrect inputs. In fact it is not possible to control anything.

I have double checked the connections, I am pretty confident that everything is correct. I also tested with another SNES controller for player 2.

Does anybody has experience with this setup or has it done before? Could it be that the missing start and select button on the original Famicom P2 controller and the existing start and select buttons on the SNES controller are causing this behaviour?

Thank you for any hints!

[P]

No, I believe the missing START and SELECT buttons is only missing hardware in the controller II itself. If you hook up a second controller I, a NES controller or a SNES controller like in your case, the second set of START and SELECT buttons should work even on old Famicoms.

That said, I don't know what to tell you except for checking the connections again. And I don't have the experience in doing this kind of mod either.

What did you do with the microphone pin though?

[saimen10]

I just left the microphone pin unconnected. Personally I do not need the microphone, as only a few games support it at all. To my understanding this should not cause any issues. Correct me if I am wrong.

I found this on nesdev link (see section "Famicom")
From reading this (though not sure if I understand it correctly), I thought maybe the problem is that start and select could possibly return 1 instead of 0. Causing problems.

Best regards!

[P]

You are right, the microphone shouldn't affect the controller. Link will be crying though.


No, that wiki section just says that the hardware in the controller II always reports START and SELECT as "0" (not pressed). If you connect a controller with START and SELECT buttons it will instead report the state of those buttons ("0" or "1" depending on if they are pressed or not), it will not cause a problem.
Since your controllers permanently reports some buttons as pressed or not, it sounds to me like you made a mistake in the wiring after all. What schematic did  you use? Could it be possible that you looked at the pinout of the port and wired it for the cable connector instead (which would be reverse of the port)?


I made a controller test program here. It comes in both ROM cartridge and FDS image versions so if you have either a flashcart or a FDSStick (or similar device) you can run it. It does not test SNES buttons and it has a bug, but it might be helpful when determining the problem as it tests both the microphone and START/SELECT. Here are a number of other programs that simply displays raw input port data (long enough reports to test the extra SNES buttons). They are ROM only though.

[saimen10]

I hope Link will forgive me. But I never could get used to the small square design of the Famicom/NES controllers. Even the controller models available for the extension port are not very comfortable compared to SNES controllers (my opinion).

Thank you very much for your input! This was my motivation to check the connections/pins for P2 again. In the end I found out that I "simply" connected the pin row shifted by one pin. As soon as I corrected this P2 now works too!

I also tested your really cool program with my FDSStick. I showed that all buttons except Select were permanently pressed. Now as everything is fixed, every button press for P2 (even Start and Select) gets recognized correctly.

Thanks again!

Best regards!

[P]

I remember when the SNES came out, the controllers were SO smooth compared to the NES controllers. And NES controllers are even less ergonomic than Famicom controllers, despite having a better placed cord.

Permanently pressed buttons is usually a sign that the signals are wired incorrectly or there is a short somewhere or something.

I'm glad my program was useful. The reason I made an FDS version of it was so that non-working controllers could be tested more easily. On a flashcart like Everdrive or Powerpak there is usually a menu that you need to navigate first, requiring a working controller just to start the program. FDSStick on the other hand doesn't have that (on newer versions you need to put only one game on it to bypass the menu).
Another reason is that people that doesn't have a flashcart might still have an FDSStick, which is much cheaper.


Also thanks for confirming my belief that the missing START and SELECT is a feature of the Controller II itself and not of the Famicom, and modding the Famicom with new controller ports easily adds those buttons.