nunchuck_funcs.h

   1 /*
   2  * Nunchuck functions  -- Talk to a Wii Nunchuck
   3  *
   4  * This library is from the Bionic Arduino course :
   5  *                          http://todbot.com/blog/bionicarduino/
   6  *
   7  * 2007 Tod E. Kurt, http://todbot.com/blog/
   8  *
   9  * The Wii Nunchuck reading code originally from Windmeadow Labs
  10  *   http://www.windmeadow.com/node/42
  11  */
  12
  13 #include <WProgram.h>
  14
  15 static uint8_t nunchuck_buf[6];   // array to store nunchuck data,
  16
  17 // Uses port C (analog in) pins as power & ground for Nunchuck
  18 static void nunchuck_setpowerpins()
  19 {
  20 #define pwrpin PORTC3
  21 #define gndpin PORTC2
  22     DDRC |= _BV(pwrpin) | _BV(gndpin);
  23     PORTC &=~ _BV(gndpin);
  24     PORTC |=  _BV(pwrpin);
  25     delay(100);  // wait for things to stabilize
  26 }
  27
  28 // initialize the I2C system, join the I2C bus,
  29 // and tell the nunchuck we're talking to it
  30 static void nunchuck_init()
  31 {
  32     Wire.begin();                // join i2c bus as master
  33     Wire.beginTransmission(0x52);// transmit to device 0x52
  34     Wire.send(0x40);// sends memory address
  35     Wire.send(0x00);// sends sent a zero.
  36     Wire.endTransmission();// stop transmitting
  37 }
  38
  39 // Send a request for data to the nunchuck
  40 // was "send_zero()"
  41 static void nunchuck_send_request()
  42 {
  43     Wire.beginTransmission(0x52);// transmit to device 0x52
  44     Wire.send(0x00);// sends one byte
  45     Wire.endTransmission();// stop transmitting
  46 }
  47
  48 // Encode data to format that most wiimote drivers except
  49 // only needed if you use one of the regular wiimote drivers
  50 static char nunchuk_decode_byte (char x)
  51 {
  52     x = (x ^ 0x17) + 0x17;
  53     return x;
  54 }
  55
  56 // Receive data back from the nunchuck,
  57 // returns 1 on successful read. returns 0 on failure
  58 static int nunchuck_get_data()
  59 {
  60     int cnt=0;
  61     Wire.requestFrom (0x52, 6);// request data from nunchuck
  62     while (Wire.available ()) {
  63         // receive byte as an integer
  64         nunchuck_buf[cnt] = nunchuk_decode_byte(Wire.receive());
  65         cnt++;
  66     }
  67     nunchuck_send_request();  // send request for next data payload
  68     // If we recieved the 6 bytes, then go print them
  69     if (cnt >= 5) {
  70         return 1;   // success
  71     }
  72     return 0; //failure
  73 }
  74
  75 // Print the input data we have recieved
  76 // accel data is 10 bits long
  77 // so we read 8 bits, then we have to add
  78 // on the last 2 bits.  That is why I
  79 // multiply them by 2 * 2
  80 static void nunchuck_print_data()
  81 {
  82     static int i=0;
  83     int joy_x_axis = nunchuck_buf[0];
  84     int joy_y_axis = nunchuck_buf[1];
  85     int accel_x_axis = nunchuck_buf[2]; // * 2 * 2;
  86     int accel_y_axis = nunchuck_buf[3]; // * 2 * 2;
  87     int accel_z_axis = nunchuck_buf[4]; // * 2 * 2;
  88
  89     int z_button = 0;
  90     int c_button = 0;
  91
  92     // byte nunchuck_buf[5] contains bits for z and c buttons
  93     // it also contains the least significant bits for the accelerometer data
  94     // so we have to check each bit of byte outbuf[5]
  95     if ((nunchuck_buf[5] >> 0) & 1)
  96         z_button = 1;
  97     if ((nunchuck_buf[5] >> 1) & 1)
  98         c_button = 1;
  99
 100     if ((nunchuck_buf[5] >> 2) & 1)
 101         accel_x_axis += 2;
 102     if ((nunchuck_buf[5] >> 3) & 1)
 103         accel_x_axis += 1;
 104
 105     if ((nunchuck_buf[5] >> 4) & 1)
 106         accel_y_axis += 2;
 107     if ((nunchuck_buf[5] >> 5) & 1)
 108         accel_y_axis += 1;
 109
 110     if ((nunchuck_buf[5] >> 6) & 1)
 111         accel_z_axis += 2;
 112     if ((nunchuck_buf[5] >> 7) & 1)
 113         accel_z_axis += 1;
 114
 115     Serial.print(i,DEC);
 116     Serial.print("\t");
 117
 118     Serial.print("joy:");
 119     Serial.print(joy_x_axis,DEC);
 120     Serial.print(",");
 121     Serial.print(joy_y_axis, DEC);
 122     Serial.print("  \t");
 123
 124     Serial.print("acc:");
 125     Serial.print(accel_x_axis, DEC);
 126     Serial.print(",");
 127     Serial.print(accel_y_axis, DEC);
 128     Serial.print(",");
 129     Serial.print(accel_z_axis, DEC);
 130     Serial.print("\t");
 131
 132     Serial.print("but:");
 133     Serial.print(z_button, DEC);
 134     Serial.print(",");
 135     Serial.print(c_button, DEC);
 136
 137     Serial.print("\r\n");  // newline
 138     i++;
 139 }
 140
 141 // returns zbutton state: 1=pressed, 0=notpressed
 142 static int nunchuck_zbutton()
 143 {
 144     return ((nunchuck_buf[5] >> 0) & 1) ? 0 : 1;  // voodoo
 145 }
 146
 147 // returns zbutton state: 1=pressed, 0=notpressed
 148 static int nunchuck_cbutton()
 149 {
 150     return ((nunchuck_buf[5] >> 1) & 1) ? 0 : 1;  // voodoo
 151 }
 152
 153 // returns value of x-axis joystick
 154 static int nunchuck_joyx()
 155 {
 156     return nunchuck_buf[0];
 157 }
 158
 159 // returns value of y-axis joystick
 160 static int nunchuck_joyy()
 161 {
 162     return nunchuck_buf[1];
 163 }
 164
 165 // returns value of x-axis accelerometer
 166 static int nunchuck_accelx()
 167 {
 168     return nunchuck_buf[2];   // FIXME: this leaves out 2-bits of the data
 169 }
 170
 171 // returns value of y-axis accelerometer
 172 static int nunchuck_accely()
 173 {
 174     return nunchuck_buf[3];   // FIXME: this leaves out 2-bits of the data
 175 }
 176
 177 // returns value of z-axis accelerometer
 178 static int nunchuck_accelz()
 179 {
 180     return nunchuck_buf[4];   // FIXME: this leaves out 2-bits of the data
 181 }