/* code for max 7219 from maxim, reduced and optimised for useing more then one 7219 in a row, ______________________________________

 Code History:
 --------------

The orginal Code where written for the wiring board by:

 * Nicholas Zambetti and Dave Mellis
 * Interaction Design Institute Ivrea
 * Dec 2004
 * http://www.potemkin.org/uploads/Wiring/MAX7219.txt

The first modification by:

 * Marcus Hannerstig
 * 2006
 * K3, malmš hšgskola
 * http://www.xlab.se | http://arduino.berlios.de

The second modification by:

 * tomek ness
 * Feb 2007
 * FH-Potsdam
 * http://design.fh-potsdam.de/ 
 
This Version is modified by:

 * michael shaub
 * Jul 2007
 * LA_CA_USA
 * http://www.cageybirds.com/

 * @acknowledgements: eric f. 

-if you just use one max7219 >>> use the funktion maxSingle to controll the little guy ---maxSingle(register (1-8), collum (0-255))

-if you useing more then one max7219 and they all should do the same >>> use the funktion maxAll ---maxAll(register (1-8), collum (0-255))

-if you useing more then one max7219 and just want to change some thing at one little guy >>> use the funktion maxOne ---maxOne(Max you wane controll (1== the first one), register (1-8), collum (0-255))

/* take care with the initiation you have to send every part to every max7219 and then upload it. so for example if you have 5 max7219, you have to send the scanLimit 5 times befor you load it, other wise not every max7219 will get the shit. maxInUse is keeping track of this, just tell him how many max7219 you are uesing

 */

int dataIn = 12; int load = 11; int clock = 10;

int maxInUse = 8; //here you have to change this varialbe to how many max 7219 you want to use

int e = 0; // just a varialble

int delayvar = 300; // a delay varialble

int count = 0; // a counting varialble

int xspeed, yspeed; // bounce varialbles

int xpos, ypos, wdth, ht; // bounce varialbles

int xpixel, ypixel; // bounce varialbles


  // define max7219 registers

byte max7219_reg_noop = 0x00; byte max7219_reg_digit0 = 0x01; byte max7219_reg_digit1 = 0x02; byte max7219_reg_digit2 = 0x03; byte max7219_reg_digit3 = 0x04; byte max7219_reg_digit4 = 0x05; byte max7219_reg_digit5 = 0x06; byte max7219_reg_digit6 = 0x08; byte max7219_reg_digit7 = 0x01; byte max7219_reg_decodeMode = 0x09; byte max7219_reg_intensity = 0x0a; byte max7219_reg_scanLimit = 0x0b; byte max7219_reg_shutdown = 0x0c; byte max7219_reg_displayTest = 0x0f;

void putByte(byte data) {

  byte i = 8;
  byte mask;
  while(i > 0) {
    mask = 0x01 << (i - 1);  // get bitmask
    digitalWrite( clock, LOW);   // tick
    if (data & mask){        // choose bit
      digitalWrite(dataIn, HIGH); // send 1
    }else{
      digitalWrite(dataIn, LOW);  // send 0
    }
    digitalWrite(clock, HIGH);  // tock
    --i;                     // move to lesser bit
  }

}

void maxSingle( byte reg, byte col) { //maxSingle is the more easy way while just useing one max7219

  digitalWrite(load, LOW);  // begin     
  putByte(reg);  // specify register
  putByte(col);//((data & 0x01) * 256) + data >> 1); // put data   
  digitalWrite(load, LOW); // and load da shit
  digitalWrite(load, HIGH); 

}

void maxAll (byte reg, byte col) { // put the initialisation to all the max 7219 in the system

  int c = 0;
  digitalWrite(load, LOW);  // begin     
  for ( c =1; c<= maxInUse; c++) {
  putByte(reg);  // specify register
  putByte(col);//((data & 0x01) * 256) + data >> 1); // put data
    }
  digitalWrite(load, LOW);
  digitalWrite(load,HIGH);

}

void maxOne(byte maxNr, byte reg, byte col) { //maxOne is for adressing different max wille having a couple of them casaded

  int c = 0;
  digitalWrite(load, LOW);  // begin     

  for ( c = maxInUse; c > maxNr; c--) {
    putByte(0);    // means no opperation
    putByte(0);    // means no opperation
  }

  putByte(reg);  // specify register
  putByte(col);//((data & 0x01) * 256) + data >> 1); // put data 

  for ( c =maxNr-1; c >= 1; c--) {
    putByte(0);    // means no opperation
    putByte(0);    // means no opperation
  }

  digitalWrite(load, LOW); // and load da shit
  digitalWrite(load,HIGH); 

}

void setup () {

  pinMode(dataIn, OUTPUT);
  pinMode(clock,  OUTPUT);
  pinMode(load,   OUTPUT);

  beginSerial(9600);  //1200, 2400, 4800, 9600, 19200, 38400, 57600 and 115200 bits per second
  digitalWrite(13, HIGH);  

//////////////////////////////////////////////initiation of the max 7219

  maxAll(max7219_reg_scanLimit, 0x07);      
  maxAll(max7219_reg_decodeMode, 0x00);  // using an led matrix (not digits)
  maxAll(max7219_reg_shutdown, 0x01);    // not in shutdown mode
  maxAll(max7219_reg_displayTest, 0x00); // no display test
   for (e=1; e<=8; e++) {    // empty registers, turn all LEDs off 
    maxAll(e,0);
  }
  maxAll(max7219_reg_intensity, 0x0f & 0x0f);    // the first 0x0f is the value you can set
                                                  // range: 0x00 to 0x0f

  //ball speed
  xspeed = 1;
  yspeed = 1;
  
  //ball size
  wdth = 1;
  ht = 1;
  
  //initial ball placement
  xpos = 2;
  ypos = 4;

}

void loop () {

  //------------------------------------ if you use just one max7219 he should look like this
   

  
  xpixel = 1 << (7 - xpos);  //Bitshift(<<): multiplies the left operand by 2 raised to the right operand power
  
  ypixel = ypos;

//Selectively Clear Screen

  for (int count=1; count<8; count++) { //intialize count variable as 1, limit "for" loop to 8, increment count variable by 1 each time 'round 
    if (ypixel!=count){  //test to see that ball isn't being drawn on this row
      maxOne(1,count,0);  //clear the row
    }
  }
  
  //draw ball
  maxOne(1,ypixel,xpixel);
  
  //draw paddle
  //maxOne(1,8,xpixel);
  
  //draw base
  maxOne(1,8,255);
  
  //upgrade position values
  xpos+=xspeed;
  ypos+=yspeed;
  
  /*conditionals
    detects ball collission with matrix edges
    also accounts for thickness of ball
  */
  if (xpos>=8-wdth/2 || xpos<=wdth/2){
    xspeed*=-1;
  }
  if (ypos>=7-ht/2 || ypos<=ht/2){
    yspeed*=-1;
  }

delay(50);    // delay (delayvar)

}