updates to the nunchuck code, to support the arduino mega, and to sup…

…port the new initialization sequence for the cheap knock-off nunchucks from ebay

Nunchuck/README

@@ -3,6 +3,11 @@ This is an arduino library for using the Wii Nunchuck.
 It uses Peter Fleury's excellent i2c library instead of Wire.h,
 slightly modified to include a timeout feature on initialization.  
 
+Recent updates:
+    August 18, 2012 - Added support for the Arduino Mega, which has a different RBx pin for the nunchuck select.
+    August 11, 2012 - Changed initialization bytes to support knock-off nunchucks
+    January 18, 2012 - Arduino 1.0 compatability fix
+
 Adam Wolf and Matthew Beckler
 Wayne and Layne, LLC
 http://wayneandlayne.com/projects/video-game-shield/

Nunchuck/examples/nunchuck_demo/nunchuck_demo.pde → Nunchuck/examples/nunchuck_demo/nunchuck_demo.ino

@@ -1,8 +1,9 @@
 /*
-   Arduino sketch to demonstrate interfacing with a Nintendo Wii Nunchuck.
+   Arduino sketch to demonstrate interfacing with a Nintendo Wii Nunchuck. It will print the nunchuck information from P1 every second, to the serial terminal at 9600 baud.
    Created by Adam Wolf and Matthew Beckler
    Wayne and Layne, LLC - http://wayneandlayne.com/projects/video-game-shield/
-   Last updated: January 16, 2010
+   Recent updates:
+        August 18, 2012 - Changed file extension to .ino for Arduino 1.0
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by

Nunchuck/nunchuck.cpp

@@ -1,7 +1,10 @@
 /*
    Nunchuck.cpp - Library for Nintendo Wii Nunchuck
    Created by Adam Wolf and Matthew Beckler (Wayne and Layne, LLC)
-   Last updated: January 18, 2012 - Arduino 1.0 compatability fix
+   Recent updates:
+    August 18, 2012 - Added support for the Arduino Mega, which has a different RBx pin for the nunchuck select.
+    August 11, 2012 - Changed initialization bytes to support knock-off nunchucks
+    January 18, 2012 - Arduino 1.0 compatability fix
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -17,8 +20,6 @@
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
-http://www.arduino.cc/playground/Main/WiiClassicController
-
  */
 
 #if defined(ARDUINO) && ARDUINO >= 100
@@ -53,7 +54,7 @@ unsigned char Nunchuck::begin(unsigned char which_nunchuck)
     joy_y_scaled_min = NUNCHUCK_JOY_Y_SCALED_MIN;
     joy_y_scaled_max = NUNCHUCK_JOY_Y_SCALED_MAX;
 
-    DDRB |= 0x10; // set DDRB4 bit = make it an output (used for nunchuck select)
+    NUNCHUCK_SELECT_SET_OUTPUT_DIR;
     this_nunchuck = which_nunchuck;
 
     if (this_nunchuck == NUNCHUCK_PLAYER_2)
@@ -62,14 +63,25 @@ unsigned char Nunchuck::begin(unsigned char which_nunchuck)
         NUNCHUCK_SELECT_P1;
 
     i2cmaster::i2c_init(); // this is non-blocking, it just sets up the baud rate generator and internal pullups
+
     if (i2cmaster::i2c_start_wait(NUNCHUCK_I2C_ADDR + I2C_WRITE, 10) == 1)
     {
         // could not access device
         return 1;
     }
-    i2cmaster::i2c_write(0x40);
+
+    // this new init bytes come from this arduino.cc forum post:
+    // http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1264805255/4#4
+    i2cmaster::i2c_write(0xF0);
+    i2cmaster::i2c_write(0x55);
+    i2cmaster::i2c_stop();
+    delay(1);
+
+    i2cmaster::i2c_start_wait(NUNCHUCK_I2C_ADDR + I2C_WRITE, 10);
+    i2cmaster::i2c_write(0xFB);
     i2cmaster::i2c_write(0x00);
     i2cmaster::i2c_stop();
+    delay(1);
 
     return 0;
 }
@@ -90,9 +102,9 @@ void Nunchuck::update()
     i2cmaster::i2c_start_wait(NUNCHUCK_I2C_ADDR + I2C_READ, 0xFFFF);
     for (unsigned char i = 0; i < 5; i++)
     {
-        nunchuck_buf[i] = decode_byte(i2cmaster::i2c_readAck());
+        nunchuck_buf[i] = i2cmaster::i2c_readAck();
     }
-    nunchuck_buf[5] = decode_byte(i2cmaster::i2c_readNak());
+    nunchuck_buf[5] = i2cmaster::i2c_readNak();
     i2cmaster::i2c_stop();
 }
 
@@ -194,11 +206,3 @@ unsigned char Nunchuck::joy_y_scaled()
     return map(constrain(nunchuck_buf[1], joy_y_min, joy_y_max), joy_y_min, joy_y_max, joy_y_scaled_min, joy_y_scaled_max);
 }
 
-
-// Internal function to decode data from nunchuck
-unsigned char decode_byte (unsigned char x)
-{
-    x = (x ^ 0x17) + 0x17;
-    return x;
-}
-

Nunchuck/nunchuck.h

@@ -1,7 +1,10 @@
 /*
    Nunchuck.h - Library for the Nintendo Wii Nunchuck
    Created by: Adam Wolf and Matthew Beckler, Wayne and Layne, LLC
-   Last updated: January 18, 2012 - Arduino 1.0 compatability fixes
+   Recent updates:
+    August 18, 2012 - Added support for the Arduino Mega, which has a different RBx pin for the nunchuck select.
+    August 11, 2012 - Changed initialization bytes to support knock-off nunchucks
+    January 18, 2012 - Arduino 1.0 compatability fix
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -46,23 +49,36 @@
 #define NUNCHUCK_JOY_Y_SCALED_MIN       0
 #define NUNCHUCK_JOY_Y_SCALED_MAX       100
 
-#define NUNCHUCK_SELECT_P1              PORTB &= 0xEF // set PB4 = low
-#define NUNCHUCK_SELECT_P2              PORTB |= 0x10 // set PB4 = high
 #define NUNCHUCK_PLAYER_1               0
 #define NUNCHUCK_PLAYER_2               1
 
+// The VGS board has the nunchuck-select signal line connected to Arduino pin D12.
+// On the UNO and compatible (atmega328p et al) D12 is PB4.
+// On the MEGA 2560 and compatible (atmega2560 et al) D12 is PB6.
+// We use an ifdef here to make our NUNCHUCK_SELECT_P{1,2} macros be correct
+#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega1281__) || defined(__AVR_ATmega2560__) || defined(__AVR_ATmega2561__)
+    #define NUNCHUCK_SELECT_SET_OUTPUT_DIR  DDRB |= 0x40  // set DDRB4 bit = make it an output (used for nunchuck select)
+    #define NUNCHUCK_SELECT_P1              PORTB &= 0xBF // set PB6 = low
+    #define NUNCHUCK_SELECT_P2              PORTB |= 0x40 // set PB6 = high
+#else
+    #define NUNCHUCK_SELECT_SET_OUTPUT_DIR  DDRB |= 0x10  // set DDRB4 bit = make it an output (used for nunchuck select)
+    #define NUNCHUCK_SELECT_P1              PORTB &= 0xEF // set PB4 = low
+    #define NUNCHUCK_SELECT_P2              PORTB |= 0x10 // set PB4 = high
+#endif
+
+
 class Nunchuck
 {
     public:
-        // returns 0=success, 1=could not access device
-        // Provide a 0 or 1 to which_nunchuck to specify which player this is
-        //   0 means "Player 1", 1 means "Player 2"
+        // Returns 0=success, 1=could not access device
+        // Argument specifies which nunchuck to initialize
+        //   pass in either NUNCHUCK_PLAYER_1 or NUNCHUCK_PLAYER_2
         unsigned char begin(unsigned char which_nunchuck);
 
         // Call this function to query the Nunchuck and update the data
         void update();
 
-        // low level functions
+        // Low level functions
         unsigned char joy_x();
         unsigned char joy_y();
         unsigned char acc_x();
@@ -91,7 +107,7 @@ class Nunchuck
         unsigned char joy_y_scaled();
 
     private:
-        // This stores the raw data from the nunchuck, properly translated
+        // This stores the raw data from the nunchuck
         unsigned char nunchuck_buf[6]; 
 
         // Stores a 0 = player 1, 1 = player 2
@@ -116,6 +132,4 @@ class Nunchuck
         unsigned char joy_y_scaled_max;
 };
 
-unsigned char decode_byte(unsigned char);
-
 #endif