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

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

SNES Buttons

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 right

NES mode 1
SNES	Gamecube
Start	Start
Select	Z
DPAD	DPAD
Y,B	B,A
Y+B+Select+left	Cstick to the right
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 right
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.

NES Buttons

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

NES mode 2
SNES	Gamecube
Start	Start
Select	Z
DPAD	DPAD
A,B	B,A
A+B+Select+left	Cstick to the right
A+B+Select+up	L+R

Enabling a mapping:

NES mode 1: Default mode.
NES mode 2: Hold A and B down when connecting the adapter.

N64 Buttons

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

The atmega88 (or atmega8 for older releases) must be programmed with one of these firmwares:

Controller type	Version	File	Target MCU	Comments
Nes/Snes	1.3	snes2wii-1.3.hex	Atmega8	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.
Nintendo 64	1.6	n64_to_wii-1.6.hex	Atmega88	First release for Atmega88 (replaces discontinued Atmega8) Support for the Rumble Pack (since 1.5)
Nes/Snes	1.1	snes2wii-1.1.hex	Atmega8	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.
Nes and Snes	1.0	snes2wii-1.0.hex	Atmega8	This was the first version. Nes or Snes mode selected with jumper.
Nintendo 64	1.4	n64_to_wii-1.4.hex	Atmega8	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 .
Nintendo 64	1.3	n64_to_wii-1.3.hex	Atmega8	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.
Nintendo 64	1.2	n64_to_wii-1.2.hex	Atmega8	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.

For this project, the appropriate fuse values are:

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

Source code

For those who are interested, here is the source code. It is released under the GPL license:

Nes and Snes version 1.3: snes2wii-1.3.tar.gz
Nes and Snes version 1.1: snes2wii-1.1.tar.gz
Nes and Snes version 1.0: snes2wii-1.0.tar.gz
Nintendo 64 version 1.2: n64_to_wii-1.2.tar.gz
Nintendo 64 version 1.3: n64_to_wii-1.3.tar.gz
Nintendo 64 version 1.4: n64_to_wii-1.4.tar.gz
Nintendo 64 version 1.6: n64_to_wii-1.6.tar.gz

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 has built:

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 :)

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Last update: June 08, 2013