Windmeadow Labs

I'm using a bit-banged i2c driver (found here: http://homepage.hispeed.ch/peterfleury/group__pfleury__ic2master.html#ga4 ) with an STK500 running an Atmega5815, but it doesn't seem to work. Using a logic analyzer, I can see that the Atmega is putting out the right bit pattern, according to my understanding of the i2c docs, but the Wiichuck never responds. Not even with an 'ack' (pulling the data line to low after the master finishes speaking) after sending 0x52. I've tried varying the speed of the data transmission, but to no avail.

I had the same problem using both the internal pull-up resistors in the wiichuck and external 4.7kOhm resistors. It seems that the wiichuck is dead to my i2c world. Except it still works just fine with the wiimote (i.e. I didn't fry nuttin').

Anyone have any ideas? This is really driving me crazy.

Im using a blackfin evaluation system at present and connected to nunchuck through I2C. I noticed that there maybe errors in the code or posts on your site and was wondering could someone check and see if they are experiencing same issue:

when decoding buttons:

On osccilloscope i get the below truth table for Z and C buttons.

When not active the lsbs of the 6th register read 11.
When Z active the lsbs of the 6th register read 00.
When C active the lsbs of the 6th register read 01.
When Z.C active the lsbs of the 6th register read 10.

therefore the above coding will not give you correct button presses.

Also i would like to know has anyone correctly decoded the acceleration bits. is the 6th register made up to msbs or lsbs and in what order as the outputs dont match what is posted.

kelly

I got this working, and have outputted the code to be interfaced with Visual Basic. If anyone is interested, I'll post a tutorial on my website.

Great write-up Chad, and it gave me all I needed to use the Nunchuk in my own project. I can control leaning in Call of Duty 4 using the Nunchuk (on my head). You can see a write-up on it here if you're interested. I reference this page a fair bit.

Thanks again!

Thank you for your code. It is great.

I am doing a project which need to have two wiimotes at the same time. Data and clock wire of one wiimotes are attach to analog pin 4 and 5 respectively. However, data and clock wire of another wiimotes need to attach to another analog pin.

I would like to ask how to change the code for the data and clock wire which are not attached to analog pin 4 and 5.

Thanks

little optimization of the print() function would be something like this :

int joy_x_axis = outbuf[0];
int joy_y_axis = outbuf[1];
int accel_x_axis = (outbuf[2] << 2) + ((outbuf[5] >> 2) & 0x03);
int accel_y_axis = (outbuf[3] << 2) + ((outbuf[5] >> 4) & 0x03);
int accel_z_axis = (outbuf[4] << 2) + ((outbuf[5] >> 6) & 0x03);
int z_button = outbuf[5] & 1;
int c_button = outbuf[5] & 2;

geting a nunchuck tomorrow and write some plain avrlibc examples :D

So, this means that somebody could manufacture adaptors that connect the nunchuk or the classic controller to usb as a gamepad, right? Or maybe an adaptor that connects the classic controller directly to the gamecube port on the wii? Are such devices availible comercially?

I have a project that I would like to use the Wiimote on however, I would like to use the Wiimote without a PC, using a microcontroller instead.

Has anyone tested the I2C port on the Wiimote to see if you can get the IR camera information directly? Or does anyone have any other ideas on how to interface the Wiimote with a microcontroller? I know you can directly interface the Nunchuck to a microcontroller, but I have not found anything that allows me to receive the IR camera data via I2C.

I've been able to run Chad's code on the Arduino but have had no success duplicating it on the SX28. The SX28 is very fast and has incredibly-tight timing so I'm wondering if the device needs some kind of timing between bytes. Any suggestions or comments in this regard are appreciated.

0xa4 write f0 55
0xa4 write fb 00
0xa4 write fa
0xa4 read 00 00 a4 20 00 00
0xa4 write f0 aa
0xa4 write 40 7a f7 1b 99 03 a2
0xa4 write 46 ab f9 44 3d e7 68
0xa4 write 4c 8a 75 5c fa
0xa4 write 20
0xa4 read 0x80,0xd4,0xa2,0x70,0xa1,0xd8,0x29,0x30
0xa4 read 0x2d,0x79,0x98,0x56,0x32,0x8d,0xeb,0x4d
0xa4 write 30
0xa4 read 0x80,0xd4,0xa2,0x70,0xa1,0xd8,0x29,0x30
0xa4 read 0x2d,0x79,0x98,0x56,0x32,0x8d,0xeb,0x4d

0xa4 write 0x00
0xa4 read 0x8f,0xd0,0xcc,0xeb,0x9c,0x13

Hi. Dear All. Above is the data what I get the nunchuk and wiimote I2C. I don't know the relation between the 0x40(wii sent 16byte key) and the return 0x20(nunchuk return 16 bytes). Below is the 0x00-0xff data what use the logic analyse write the nunchuk 00-ff data. Who know this relation? Let's discuss together! cokeliu@ev-sparkle.com

0x 0---0x81, 0x81, 0xad, 0x7f, 0x7b, 0xbf, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0,
0x10---0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7c,
0x20---0x7c, 0x7d, 0x7b, 0x 9, 0xaf, 0xae, 0xad, 0x13, 0xdf, 0x18, 0x81, 0xe3, 0x20, 0x81, 0xeb, 0x40,
0x30---0x7c, 0x7d, 0x7b, 0x 9, 0xaf, 0xae, 0xad, 0x13, 0xdf, 0x18, 0x81, 0xe3, 0x20, 0x81, 0xeb, 0x40,
0x40---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0x50---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0x60---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0x70---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0x80---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0x90---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xa0---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xb0---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xc0---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xd0---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xe0---0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xf0---0x55, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0x 0, 0xa4, 0x20, 0x 0, 0x 0,

I found a pinout here http://www.hardwarebook.info/Wiimote_Expansion_Port so rather than cut the cable I plugged jumper wires into the connector.

Depending on how I wire it, it either hangs, or returns the following values
46 46 187 185 184 0 1
over and over

I'm using arduino decimilia, arduino alpha 0010

I got the code to work on a PIC 18F2550 running at 48MHz on 3.3V and 300kHz I2C. I used Microchip's Student Edition C18 compiler and its library (the documentation is horrible) for controlling the hardware I2C on the chip. At 3.3V (I'm using a PICKit 2 programmer, which provides power from USB at 2.5V to 5.0V), the highest speed I got was 300kHz. Any higher and it would begin to output garbage. Also, I used only 1900 cycles, or about 158 microseconds, of delay between sending the 0x00 and reading data. 1800 cycles would not work.

Huge thanks to chad for the wiring, protocol, and sample code and Edward for the required delays and the lower-level code I needed for the PIC's MMSP module.

I can not post my code; I apologize in advance for anyone who needs it.

-Xo W.

I'm a bit of a newbie to all this, however I've successfully got this hack to work and am now keen on sending out the nunchuck's sensor data via midi. Tod Kurt did some great work with his recent 'Bionic Arduino' class and so I contacted him and he graciously replied. The probelm is that I may not have made it clear enough how much of a beginner I am. Anyway, I've begun modifying his version of the above code but I was wondering if anyone else has tried to send MIDI data from the nunchuck? and if so would they like to help me achieve results?

/* Nunchuck to MIDI
*
* Based upon:
* NunchuckServo 2007 Tod E. Kurt, http://todbot.com/blog/
*
* The Wii Nunchuck reading code is taken from Windmeadow Labs
* http://www.windmeadow.com/node/42
*/

#include

#define middleC 60
#define LEDpin 13

//Variables
int ledPin = 13;

void setup()
{
Serial.begin(31250); //baud rate for MIDI

nunchuck_init(); // send the initilization handshake
Serial.print ("Finished setup\n");
}

void loop()
{

//THIS IS WHERE I NEED TO 'CAPTURE' THE NUNCHUCK VALUES

nunchuck_get_data();
nunchuck_print_data();
delay(100);
}

//
// Nunchuck functions
//

static uint8_t nunchuck_buf[6]; // array to store nunchuck data,

// initialize the I2C system, join the I2C bus,
// and tell the nunchuck we're talking to it
void nunchuck_init()
{
Wire.begin(); // join i2c bus as master
Wire.beginTransmission(0x52); // transmit to device 0x52
Wire.send(0x40); // sends memory address
Wire.send(0x00); // sends sent a zero.
Wire.endTransmission(); // stop transmitting
}

// Send a request for data to the nunchuck
// was "send_zero()"
void nunchuck_send_request()
{
Wire.beginTransmission(0x52); // transmit to device 0x52
Wire.send(0x00); // sends one byte
Wire.endTransmission(); // stop transmitting
}

// Receive data back from the nunchuck,
int nunchuck_get_data()
{
int cnt=0;
Wire.requestFrom (0x52, 6); // request data from nunchuck
while (Wire.available ()) {
// receive byte as an integer
nunchuck_buf[cnt] = nunchuk_decode_byte(Wire.receive());
cnt++;
}
nunchuck_send_request(); // send request for next data payload
// If we recieved the 6 bytes, then go print them
if (cnt >= 5) {
return 1; // success
}
return 0; //failure
}

// Print the input data we have recieved
// accel data is 10 bits long
// so we read 8 bits, then we have to add
// on the last 2 bits. That is why I
// multiply them by 2 * 2
void nunchuck_print_data()
{
static int i=0;
int joy_x_axis = nunchuck_buf[0];
int joy_y_axis = nunchuck_buf[1];
int accel_x_axis = nunchuck_buf[2]; // * 2 * 2;
int accel_y_axis = nunchuck_buf[3]; // * 2 * 2;
int accel_z_axis = nunchuck_buf[4]; // * 2 * 2;

int z_button = 0;
int c_button = 0;

// byte nunchuck_buf[5] contains bits for z and c buttons
// it also contains the least significant bits for the accelerometer data
// so we have to check each bit of byte outbuf[5]
if ((nunchuck_buf[5] >> 0) & 1)
z_button = 1;
if ((nunchuck_buf[5] >> 1) & 1)
c_button = 1;

if ((nunchuck_buf[5] >> 2) & 1)
accel_x_axis += 2;
if ((nunchuck_buf[5] >> 3) & 1)
accel_x_axis += 1;

if ((nunchuck_buf[5] >> 4) & 1)
accel_y_axis += 2;
if ((nunchuck_buf[5] >> 5) & 1)
accel_y_axis += 1;

if ((nunchuck_buf[5] >> 6) & 1)
accel_z_axis += 2;
if ((nunchuck_buf[5] >> 7) & 1)
accel_z_axis += 1;

Serial.print(i,DEC);
Serial.print("\t");

Serial.print("joy:"); //tag
Serial.print(joy_x_axis,DEC); //x axis value
Serial.print(","); //next value
Serial.print(joy_y_axis, DEC); //y axis value
Serial.print(" \t");

Serial.print("acc:");
Serial.print(accel_x_axis, DEC);
Serial.print(",");
Serial.print(accel_y_axis, DEC);
Serial.print(",");
Serial.print(accel_z_axis, DEC);
Serial.print("\t");

Serial.print("but:");
Serial.print(z_button, DEC);
Serial.print(",");
Serial.print(c_button, DEC);

Serial.print("\r\n"); // newline
i++;
}

// Encode data to format that most wiimote drivers except
// only needed if you use one of the regular wiimote drivers
char nunchuk_decode_byte (char x)
{
x = (x ^ 0x17) + 0x17;
return x;
}

// returns zbutton state: 1=pressed, 0=notpressed
int nunchuck_zbutton()
{
return ((nunchuck_buf[5] >> 0) & 1) ? 0 : 1; // voodoo
}

// returns zbutton state: 1=pressed, 0=notpressed
int nunchuck_cbutton()
{
return ((nunchuck_buf[5] >> 1) & 1) ? 0 : 1; // voodoo
}

// returns value of x-axis joystick
int nunchuck_joyx()
{
return nunchuck_buf[0];
}

// returns value of y-axis joystick
int nunchuck_joyy()
{
return nunchuck_buf[1];
}

// returns value of x-axis accelerometer
int nunchuck_accelx()
{
return nunchuck_buf[2]; // FIXME: this leaves out 2-bits of the data
}

// returns value of y-axis accelerometer
int nunchuck_accely()
{
return nunchuck_buf[3]; // FIXME: this leaves out 2-bits of the data
}

// returns value of z-axis accelerometer
int nunchuck_accelz()
{
return nunchuck_buf[4]; // FIXME: this leaves out 2-bits of the data
}

So I just finished getting this hack working on a PIC24F. Thanks a lot chad and everyone else for sharing your knowledge!

For a while I was having the same problem others have reported here with the nunchuck always replying with 0xFF. The solution was a ~20ms delay prior to sending the initialization request (0x40, 0x00), and then a ~1 ms delay between sending the request byte (0x00) and reading the data was required. Those times may be high, as I haven't spent much time trying to find the true minimums. The Arduino code probably runs slow enough between those routines that it fulfills the timing requirements w/o extra delay.

Anyways, I wanted to share that, in case it helps someone avoid hours of needless debuggin. Also, I will post my sample code later today or tomorrow in case anyone is interested.

Anyone get this to work on a PIC? I'm on the CCS forums trying to get the I2C stuff to work (http://www.ccsinfo.com/forum/viewtopic.php?t=32753)

If anyone has suggestions please post them!
-Daniel