N64/Snes/Nes controller to gamecube/Wii conversion project

Project overview
Compatibilty
SNES Support
NES Support
N64 Support
Schematic
Printed circuit board (PCB)
Firmware
Pictures
User pictures
Links
Disclaimer

Project overview

Nintendo's idea of implementing support for NES, SNES and N64 games in their new console, the Wii, is in my opinion one of their greatest ideas. As soon as I learned that it would be possible to use Gamecube controllers to play those games, I started thinking about designing an Snes/Nes controllers to Gamecube adapter which would be compatible with the Wii.

Update!: Since the Wii U and new Wii models are built without gamecube ports, I have created a new project that works via the Wiimote, making it possible to continue enjoying the classics with proper controllers.

As soon as I got access to a Wii (I still dont have mine), I started testing my code which I had prepared in advance. I started by doing the NES and SNES adapter. Later, since a friend kept insisting that I should also design a N64 to Gamecube/Wii adapter, I implemented such an adapter.

Because of the complexity of the Gamecube's controller protocol, it's not possible to build a simple conversion circuit without using programmable components. For this project, I used an atmel Atmega8 microcontroller. Maybe it's a little overkill, but using this chip allowed me to use my Multiuse tiny 1 PCB. Given the small size of this circuit, it's possible to fit it inside an original controller.

Here are a few example of what can be done with this circuit:

An Snes controller clone converted to Gamecube/Wii

A NES controller converted to Gamecube/Wii

N64 controller to Gamecube/Wii adapter cable

Snes controller to Gamecube/Wii adapter cable

(for more pictures, visit the pictures section)

Preassembled N64 to Gc/Wii adapters available

Preassembled SNES to Gc/Wii adapters available

Compatibilty

2015-12-26: As I have been asked many times if the adpater is compatible with something, I decided to create this table. The adapter should work with all games or systems supporting Gamecube controllers, but there are exceptions.

Game/system/controller	Compatible?
Virtual console games on Wii	Yes
Not64 emulator	Yes
Mario Kart Wii	Yes
Hori mini 64 controller	Yes
Homebrew browser	Yes
Wii U	No as there are no Gamecube ports.
Gamecube adapter for Wii U	No^[1]
Gameboy player and SNES adapter	Yes
Gameboy player and N64 adapter	No^[1]

^[1] Adapters, games or system polling the controller (in fact, the adapter) at high frequency (i.e. More than 60Hz) prevent the adapter from working correctly.

SNES Support

SNES mode
SNES	Gamecube
Start	Start
Select	Z
DPAD	DPAD
Y,X,B,A,L,R	Y,X,B,A,L,R
L+R+Select+left	Cstick to the left^[1]

NES mode 1
SNES	Gamecube
Start	Start
Select	Z
DPAD	DPAD
Y,B	B,A
Y+B+Select+left	Cstick to the left^[1]
Y+B+Select+up	L+R

NES mode 2
SNES	Gamecube
Start	Start
Select	Z
DPAD	DPAD
Y,B	A,B
Y+B+Select+left	Cstick to the left^[1]
Y+B+Select+up	L+R

Enabling a mapping:

SNES mode: Default mapping.
NES mode 1: Hold START at power up.
NES mode 2: Hold START, Y and B at power up.

Supported controllers:

Official Nintendo controllers (North america, Europe and Japan)
Most, if not all, third party controllers.
The "Hori Super Game Boy Controller"

Please let me know of any special controllers you use with this adapter!

^[1]Before firmware version 1.4, this combo sent the C-Stick to the right

NES Support

NES mode 1
NES	Gamecube
Start	Start
Select	Z
DPAD	DPAD
A,B	A,B
A+B+Select+left	Cstick to the left^[1]
A+B+Select+up	L+R

NES mode 2
NES	Gamecube
Start	Start
Select	Z
DPAD	DPAD
A,B	B,A
A+B+Select+left	Cstick to the left^[1]
A+B+Select+up	L+R

NES mode 3
NES	Gamecube
Start	Start
Select	Y
DPAD	DPAD
A,B	A,B
A+B+Select+left	Z
A+B+Select+up	X

Enabling a mapping:

NES mode 1: Default mode.
NES mode 2: Hold A and B down when connecting the adapter.
NES mode 3: Not implemented yet.

^[1]Before firmware version 1.4, this combo sent the C-Stick to the right

N64 Support

N64 version:
The adapter supports many different mappings, which are appropriate for a wide range of Wii virtual console and Gamecube games. Here's a file containing a table of the different mappings supported:
n64_mapping_table1.4.pdf

Schematic

Here is a picture of the schematic. Click for bigger version:

Nes/Snes version:	N64 version:

Comments and explainations:
The microcontroller is powered with 5 volts for three reasons:

Snes and Nes controllers work at 5 volts. This means that it's better to use 5 volts for a logic 1 when driving the controller's CLock and Latch pins. (As I dont have the official controller specifications, I cannot know for sure what is the voltage threshold for a logic 1.
The data signal from the controller is at 5 volts when high. To prevent exposing the microcontroller input to voltages higher than it's own, it would have been necessary to use a voltage divider which would have required two additional resistors.
If I had powered the MCU with only 3.3 volts, I would have had to use an ATmega8L which cannot run at clock rates above 8 mhz.

On the gamecube side, the data signal is held at 3.43 volts via a pullup resistor inside the Gamecube. When someone (gamecube or controller) wishes to set the signal to 0, it just has to pull the signal to ground. Otherwise, it just leave-it as-is. I acheive this by playing with the Atmega8 pin direction. To send a 0, I configure it as output-low. Otherwise, I configure it as input-no_pullup. Activating the internal pullup or sending a 1 in output mode must not be done since this would put 5 volts on the data line. Who knows if this could damage the console port? (In fact, I have a cheap wireless controller which drives the bus with 5 volts! Nothing seems to have been damaged though...)

The N64 version uses the same technique to control the controller's data line. The only difference is that we have to provide the 3.43 volts pullup resistor. (From the controller's point of view, we're the console!)

FAQ:
Q: Why did'nt you use the Wiimote accessory connector instead of doing a Gamecube adapter?
A: I considered it, but I decided that using the Gamecube ports was better. Here are a few reasons:

NES and SNES controllers use 5 volts. If I remember correctly, there is no 5 volts in the Wiimote connector. This means that I would need to build a step-up switching voltage regulator. Higher cost, Higher complexity.
NES and SNES controllers were designed to be wired controllers. This means that they probably did not have low power consumption in mind when the designed it. But I did not take the time to very that because of point #1
The Connector is proprietary. Gamecube connectors are too, but they can be easily obtained from extension cables, which are cheap and easy to find. At the time, I failed to find wiimote extension cables
NES/SNES (and other consoles) emulators on Wii are (or were, I have not checked recently) in fact Gamecube based. Since Gamecube games only support Gamecube accessory, implementing the adapter via the Wiimote would be useless.
I'm not a big fan of wireless things. Besides, the NES/SNES controller cables never bothered me.

Printed circuit board (PCB)

As I said in the overview, I used my Multiuse tiny1 PCB. Refer to the Multiuse tiny1 page for more information. If you dont feel like building it yourself, I sell fully assembled PCBs with the MCU pre-programmed in my online shop.

Here are pictures and wiring diagrams:

Very small PCB

(S)NES Wiring diagram

N64 Wiring diagram

When using the Multiuse tiny1 PCB for this project, only the following components are needed. Suggested Digikey part numbers are included:

Reference	Description	Comments	Digikey part #
C1	10uf capacitor	1uf is enough too. And smaller value capacitors are slimmer.	490-1835-1-ND
C2,C3	18pf capacitor	Change as appropriate for crystal.	311-1102-1-ND
Y1	16mhz crystal	Suggested part number is for a surface mount crystal. Can be easily soldered on the thru-hole footprint.	644-1037-1-ND
R3,R5,R6	0 ohms resistor	You can do a solder bridge instead.	N/A
U2	Atmega8 microcontroller	It is important that you use the family supporting a 16 mhz speed. The Atmega8L-* family does not go above 8mhz.	ATMEGA8-16AU-ND

Pre-assembled NES/SNES to Gamecube/Wii circuits available

Pre-assembled N64 to Gamecube/Wii circuits available

Firmware

NES/SNES to GC/Wii releases

Version v1.5.1 March 26, 2016 (Saturday)
Small corrections: Fixed a long standing bug where random button press would occur when no controller (NES/SNES) was present. Corrected fuse values in Atmega168 makefile
File(s): snes2wii-1.5.1.m8.hex (3.3 KB) snes2wii-1.5.1.m168.hex (3.5 KB) snes2wii-1.5.1.tar.gz (16.1 KB)

Show previous releases...

Version v1.5 February 9, 2016 (Tuesday)
Add ATmega168 support (Build .m8 = Atmega8, Build .m168 = Atmega168)
File(s): snes2wii-1.5.m8.hex (3.3 KB) snes2wii-1.5.m168.hex (3.5 KB) snes2wii-1.5.tar.gz (15.8 KB)

Version v1.4.1 April 25, 2014 (Friday)
Changes in this version: NES/SNES controller polling frequency increased from 60Hz to 200Hz to reduce latency.
File(s): snes2wii-1.4.1.hex (3.3 KB) snes2wii-1.4.1.tar.gz (16.9 KB)

Version v1.4 April 25, 2014 (Friday)
Changes in this version: Button combos used to simulate the C-Stick moving towards the right: Modified to send a movement to the left. (For SNES9xGX and FCE Ultra GX) Source code updates for modern avr-libc.
File(s): snes2wii-1.4.hex (3.2 KB) snes2wii-1.4.tar.gz (16.7 KB)

Version v1.3 May 22, 2013 (Wednesday)
Changes in this version: Added a feature to swap the NES A and B buttons. Hold A and B at power up to use it.
File(s): snes2wii-1.1.hex (3.1 KB) snes2wii-1.1.tar.gz (16.5 KB)

Version v1.1 September 15, 2007 (Saturday)
Changes in this version: NES mode can be forced on by holding the Start button at power-up. Without this, in my opinion, NES games are almost unplayable with an SNES controller. Implemented button combinations which can affect how unaccessible Gamecube buttons and sticks are reported. eg: Sending L+R pressed with a NES controller, and sending CStick towards the right. Mostly useful to summon some emulator's menu while playing. Implemented new Gamecube commands for better compatibility, eg: GCLinux.
File(s): snes2wii-1.1.hex (3.1 KB) snes2wii-1.1.tar.gz (16.5 KB)

Version v1.1
September 15, 2007 (Saturday)

Changes in this version:

NES mode can be forced on by holding the Start button at power-up. Without this, in my opinion, NES games are almost unplayable with an SNES controller.
Implemented button combinations which can affect how unaccessible Gamecube buttons and sticks are reported. eg: Sending L+R pressed with a NES controller, and sending CStick towards the right. Mostly useful to summon some emulator's menu while playing.
Implemented new Gamecube commands for better compatibility, eg: GCLinux.

File(s):
snes2wii-1.1.hex (3.1 KB)
snes2wii-1.1.tar.gz (16.5 KB)

Version v1.0 February 28, 2007 (Wednesday)
This was the first version. Nes or Snes mode selected with jumper.
File(s): snes2wii-1.0.hex (2 KB) snes2wii-1.0.tar.gz (13.2 KB)

This project is also available on GitHub!
To request features, report issues or contribute, you may send me an email or use the GitHub repository:
https://github.com/raphnet/snes2wii

N64 to GC/Wii releases

Version v1.7 February 11, 2016 (Thursday)
Compatiblity fix for Gameboy player: When a very high poll frequency is detected, disables rumble. ATmega168 MCU support
File(s): n64_to_wii-1.7.tar.gz (85.3 KB) n64_to_wii-1.7.m8.hex (5.7 KB) n64_to_wii-1.7.m88.hex (5.7 KB) n64_to_wii-1.7.m168.hex (5.9 KB)

Show previous releases...

Version v1.6 June 8, 2010 (Tuesday)
For Atmega88 Support for the Rumble Pack (since 1.5)
File(s): n64_to_wii-1.6.hex (5.7 KB) n64_to_wii-1.6.tar.gz (88.2 KB)

Version v1.5 December 18, 2008 (Thursday)
Implemented the rumble feature
File(s): n64_to_wii-1.5.hex (5.6 KB) n64_to_wii-1.5.tar.gz (99.6 KB)

Version v1.4 March 16, 2008 (Sunday)
New in this version: Added 4 new button mappings, accessible by holding a C button for each mapping. These are reported to be useful for Super Smash bros Melee and Brawl. Created a single page PDF documenting the supported mappings .
File(s): n64_to_wii-1.4.hex (5.2 KB) n64_to_wii-1.4.tar.gz (84.7 KB)

Version v1.3 October 16, 2007 (Tuesday)
New in this version: It is now possible to disable the feature where the L and Z buttons are swapped by holding the 'L' button down when plugging the adapter in the console. If the R button is held down when plugging the adapter into the console, the N64 C-left and C-right buttons are mapped to the Gamecube Y and X buttons. This makes it possible to play the virtual console game Sin and Punishment. The joystick sensitivity can be increased by holding the Dpad right button when plugging the adapter into the console. The joystick sensitivity can be decreased by holding the Dpad left button when plugging the adapter into the console.
File(s): n64_to_wii-1.3.hex (3.6 KB) n64_to_wii-1.3.tar.gz (17.7 KB)

Version v1.3
October 16, 2007 (Tuesday)

New in this version:

It is now possible to disable the feature where the L and Z buttons are swapped by holding the 'L' button down when plugging the adapter in the console.
If the R button is held down when plugging the adapter into the console, the N64 C-left and C-right buttons are mapped to the Gamecube Y and X buttons. This makes it possible to play the virtual console game Sin and Punishment.
The joystick sensitivity can be increased by holding the Dpad right button when plugging the adapter into the console.
The joystick sensitivity can be decreased by holding the Dpad left button when plugging the adapter into the console.

File(s):
n64_to_wii-1.3.hex (3.6 KB)
n64_to_wii-1.3.tar.gz (17.7 KB)

Version v1.2 August 15, 2007 (Wednesday)
Version 1.1 for N64 had a reliability bug which caused some controllers to randomly reset and recalibrate during play. This is fixed in version 1.2. It is recommended that you upgrade even if version 1.1 is working for you.
File(s): n64_to_wii-1.2.hex (2.9 KB) n64_to_wii-1.2.tar.gz (14.6 KB)

This project is also available on GitHub!
To request features, report issues or contribute, you may send me an email or use the GitHub repository:
https://github.com/raphnet/n64_to_wii

For this project, the appropriate fuse values are:

ATMEGA168 builds: high byte = 0xdc, low byte = 0xd7, extended byte = 0x01
ATMEGA88 builds: high byte = 0xd9, low byte = 0xdf, extended byte = 0x07
ATMEGA8 builds: high byte = 0xc9, low byte = 0x9f

For details about how to program an AVR, visit my AVR programming page.

Pre-programmed Atmega8 (DIP package) available

The source code (.tar.gz files above) is released under the GPL license.

I coded the project in avr-as (gnu) assembler. A makefile is included. Why I used assembly language? Mostly for speed and timing control. The smallest time unit in the gamecube controller protocol is of 1us, which corresponds to only 16 cpu cycles at 16 mhz. Not much time to waste at that speed. Because I used assembly, many optimisations tricks were possible.

Pictures

Converting a NES controller: (Beware: Clone controllers use different colors)

Inside an original NES controller

Result

Next to the Wii

Super mario bros

Converting an SNES controller: (Beware: Clone controllers use different colors)

Inside an SNES controller clone

Result

Next to the Wii

Super mario world

Nintendo 64 version:

Pictures taken during the development and debugging:

The development was done at my Lucky-Wii-owner friend's place...

Analysing the protocol with an home-made tool.

Reprogramming the adapter

It almost works... The Wii recognizes the controller!

Pictures taken during tests, when it was finally working:

The prototype:

Overview

Closer view

Pre-converted Original NES controllers available

User pictures

I like to see how others build my projects. It also makes good assembly examples. Please send me your pictures and I'll add them here.

Andrew Jalics has posted pictures of the NES to Wii box he build using my PCB on his web site.:

Declan Williams, from Autralia, built the Nes/Snes and N64 versions. He used pre-programmed chips from my store and created his own PCBs. He also built his own SNES style connector ( details visible on his 4nes4snes pictures):

June 5, 2009: Andrew Kay sent me the following pictures of the adapter he built:

July 19, 2014 (Saturday)
TALENTO from Bulgaria sent me pictures of the SNES to Wii/Gamecube adapter he built using a generic board bought on eBay.

July 19, 2014 (Saturday)
Jonathan sent me the following pictures of a controller he converted:

July 31, 2020 (Friday)
Jonh built the circuit and put together this nice little SNES to Gamecube adapter:

Links

This document clearly explains the low level communication of the gamecube controllers:
Nintendo Gamecube Controller Protocol

This document contains a section (#9) with information on the bit significations of the controller replies to various commands:
Yet Another Gamecube Documentation

This page contains documentation about the snes controller 'protocol':
Sci.Electronics FAQ: Super Nintendo Entertainment System: pinouts & protocol

Disclaimer

I cannot be held responsible for any damages that could occur to you or your equipment while following the procedures present on this page. Also, I GIVE ABSOLUTELY NO WARRANTY on the correctness and usability of the informations on this page. Please note, however, that the procedures above have worked in my case without any damages or problems.

Now you cannot say that I did not warn you :)