Wiimote/Extension Controllers

The Wiimote includes a 6-pin expansion port that allows external peripherals to be connected to it. Communications are bidirectional synchronous serial (the protocol is unknown), and the devices provide a virtual register block of length 0x100 that is mapped at 0xa40000 in the Wiimote's address space. Communications are encrypted, as detailed in Wiimote#Extension Controllers. Nintendo has currently released two extensions, the Nunchuk and the Classic Controller. In addition, Guitar Hero guitars also act as extension controllers. The Balance board acts like a dummy Wiimote with its own type of extension controller.

Peripheral Protocol is 400kHz "fast" I2C, with slave address 0x52. It should be possible to make homebrew peripherals; see the Tenkey project (japanese) or the Twiidler project

Nunchuk

The Nunchuk is identified by the 16-bit constant 0x0000 (0xFEFE encrypted) at register address 0xa400fe. It provides three-axis acceleration data, two digital buttons, and an X-Y analog stick.

Data Format

The Nunchuk reports its information as 6 bytes of data, readable at 0xa40008 and streamable using Data Reporting Modes that include Extension bytes (unused bytes are filled with 0x00). The data is packed into the six bytes as follows (after decryption):

	Bit
Byte	7	6	5	4	3	2	1	0
0	SX<7:0>
1	SY<7:0>
2	AX<7:0>
3	AY<7:0>
4	AZ<7:0>
5	Unknown						BC	BZ

SX,SY are the Analog Stick X and Y positions, while AX, AY, and AZ are the accelerometer data (in the same format as described in Wiimote#Accelerometer). BC and BZ are the state of the C and Z buttons (0=pressed).

Nintendo games calibrate the center position of the Analog Stick upon power-up or insertion of the Nunchuk.

Wireless Nunchuk

It looks like Wireless Nunchuks operate differently than the original Nunchuk-Extension. Anyone have a clue?

Nyko Kama

The Nyko Kama is just a simple wireless Nunchuk, with a Sync and Power button. It uses two AAA batteries.

The Nyko Kama does not work with current homebrew or PC Wiimote software. It is unknown how to make it work.

Datel Blade-FX

This wireless Nunchuk can emulate either a Nunchuk or a Classic Controller. At startup it behaves like a Nunchuk, but pressing the "Classic" button puts it into Classic Controller mode. While in Classic Controller mode, the FUNCTION LED will be solidly lit (red). Classic controller emulation allows it to be used in the Wii system menu, with the joystick controlling the cursor, and the Z button selecting, and the C button having no visible effect. It also allows it to work (according to the instructions) with some Virtual Console games.

This wireless Nunchuk also has a cheat feature that remembers a motion that you do and repeats it continuously without you having to keep doing the motion. That is done with the "FX" button.

There is also a "SYNC" button where the cord would be. Pressing it once connects the wireless nunchuk. While connected, the STATUS LED will slowly flash.

When the wireless adapter is plugged in, but the wireless nunchuk has not been synced or turned on, then it behaves as though nothing was plugged in. No status report is generated when the wireless adapter is plugged in or unplugged, unless the nunchuk is synced. Querying the status report returns 0 for the extension flag (instead of 2).

But when the wireless nunchuk is synced, then it behaves strangely. It sends a status report indicating that an extension is connected, but trying to read the 16 bytes from 0xF0 of the expansion (to identify the expansion) successfully returns "FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF". Trying to read the 16 bytes from 0x20 (to read the calibration) has the same effect.

Then it sends a status report saying no expansion is connected (possibly in response to something GlovePIE does). And GlovePIE's subsequent attempt to read the 16 bytes at 0x30 (more calibration) fails with error code 7.

0.5 seconds later it sends another status report saying that an expansion IS connected. And the process is repeated. Note that it stays connected for only a few milliseconds, then stays disconnected for 0.5 seconds.

Expansion data in the input reports is all 0xFF.

It is not yet known how to make the Datel Blade-FX work, although it could currently theoretically be detected when it is synced, due to its strange behaviour.

CarlKenner 07:47, 20 November 2008 (UTC)

Classic Controller

The Classic Controller is identified by the 16-bit constant 0x0101 (0xFDFD encrypted) at register address 0xa400fe. It provides 15 buttons, two of which are analog triggers and provide both "clicked" status and a distance pressed measurement, and two X-Y analog sticks.

Data Format

The Classic Controller reports its information as 6 bytes of data, readable at 0xa40008 and streamable using Data Reporting Modes that include Extension bytes (unused bytes are filled with 0x00). The data is packed into the six bytes as follows (after decryption):

	Bit
Byte	7	6	5	4	3	2	1	0
0	RX<4:3>		LX<5:0>
1	RX<2:1>		LY<5:0>
2	RX<0>	LT<4:3>		RY<4:0>
3	LT<2:0>			RT<4:0>
4	BDR	BDD	BLT	B-	BH	B+	BRT	1
5	BZL	BB	BY	BA	BX	BZR	BDL	BDU

LX,LY are the left Analog Stick X and Y (0-61), RX and RY are the right Analog Stick X and Y (0-31), and LT and RT are the Left and Right Triggers (0-31). The left Analog Stick has twice the precision of the other analog values.

BD{L,R,U,D} are the D-Pad direction buttons. B{ZR,ZL,A,B,X,Y,+,H,-} are the discrete buttons. B{LT,RT} are the digital button click of LT and RT. All buttons are 0 when pressed.

Nintendo games calibrate the center position of the Analog Sticks upon power-up or insertion of the Classic Controller.

Guitar Hero Guitar

The Guitar is identified by the 16-bit constant 0x0103 (0xFDFB encrypted) at register address 0xa400fe. It a two-axis analog thumbstick, a one-axis analog "whammy bar" and 9 buttons.

Data Format

The Guitar reports its information as 6 bytes of data, readable at 0xa40008 and streamable using Data Reporting Modes that include Extension bytes (unused bytes are filled with 0x00). The data is packed into the six bytes as follows (after decryption):

	Bit
Byte	7	6	5	4	3	2	1	0
0	SX<7:0>
1	SY<7:0>
2	Unknown
3	WB<7:0>
4	?	BD	?	B-	?	B+	?	?
5	BO	BR	BB	BG	BY	?	?	BU

SX,SY are the Analog Stick X and Y positions. BG,BR,BY,BB,BO are the fret buttons by color (Green, Red, Yellow, Blue, Orange). B-,B+ are the + and - buttons at the base of the controller. BU and BD are up and down on the strum bar, respectively. WB is the analog whammy bar.

Balance Board

The Balance Board extension is identified by the 16-bit constant 0x2A2C (0x0402 encrypted) at register address 0xa400fe. This extension is only found connected to the Wii Balance Board device, and is documented on that page.