SADI Interaction Design Lab

//**************************************************************//
//  Name    : shiftPWMout                                       //
//  Author  : D. Cuartielles                                    //
//  Date    : 24 Sept, 2007                                     //
//  Version : 1.0                                               //
//  Notes   : Code for using Sadi's 32OUTPUT board              //
//          : to count from 0 to 255                            //
//  Acknowledgements: gonium.net for the original timer         //
//****************************************************************

//Pin connected to ST_CP of 74HC595
//int latchPin = 10;
//Pin connected to SH_CP of 74HC595
//int clockPin = 9;
////Pin connected to DS of 74HC595
//int dataPin = 8;

//#include < avr / interrupt.h > 
//#include < avr / io.h > 

#define INIT_TIMER_COUNT 6 
#define RESET_TIMER2 TCNT2 = INIT_TIMER_COUNT 

int int_counter = 0; 
volatile int second = 0; 
int oldSecond = 0; 
long starttime = 0; 
int numPWMs = 32;
int msTick = 0;
int duration[]= {
  0,0,0,0, 0,0,0,0,
  0,0,0,0, 0,0,0,0,
  0,0,0,0, 0,0,0,0,
  0,0,0,0, 0,0,0,0          };    //internal timer for current note  

int flags[]= {
  0,0,0,0, 0,0,0,0,
  0,0,0,0, 0,0,0,0,
  0,0,0,0, 0,0,0,0,
  0,0,0,0, 0,0,0,0          };    //internal flags, 0=nothing happens, 1=fade in, 2=fade out 

int cont = 1;
int tendency = 1;
int sizePeriod = 63;


void shiftOutLSB(byte val)
{
  int i;

  for (i = 0; i < 8; i++)  {
    if (val>>i & B1) PORTB |= B1;
    else PORTB &= ~B1;
    PORTB |= B10;
    //delayMicroseconds(1);
    PORTB &= ~B10;       
  }
}

void fadeout(int pin) {
  flags[pin-1] = 1;
}

void fadein(int pin) {
  flags[pin-1] = 2;
}

ISR(TIMER2_OVF_vect) { 
int adder = 0;
  RESET_TIMER2; 
  int_counter += 1; 
  if (int_counter == 1000) { 
    second+=1; 
    int_counter = 0; 
    adder = 1;
  }  

  int pinSetA = 0;
  int pinSetB = 0;

  msTick++;                                //increment timer tick at 1 ms intervals
  if (msTick > sizePeriod) msTick = 0;

  //check flags
  for (int i = 0; i < numPWMs; i++)
    switch (flags[i]) { 
    case 1:
      if (duration[i] > 0) duration[i] -= adder;
      else flags[i] = 0;
      break;
    case 2:
      if (duration[i] < sizePeriod) duration[i] += adder;
      else flags[i] = 0;
      break;
    default:
      break;
    }

  for (int i = 0; i < numPWMs; i++)
    if(i<numPWMs/2) pinSetA |= ((msTick<duration[i])<<i);
    else pinSetB |= ((msTick<duration[i])<<(i-numPWMs/2));

  PORTB &= ~B100;
  shiftOutLSB(pinSetA & B11111111);
  shiftOutLSB(pinSetA>>8);
  shiftOutLSB(pinSetB & B11111111);
  shiftOutLSB(pinSetB>>8);
  PORTB |= B100;

}; 

void setup() {
  //set pins to output because they are addressed in the main loop
  //pinMode(latchPin, OUTPUT);
  //pinMode(clockPin, OUTPUT);
  //pinMode(dataPin, OUTPUT);
  // To accelerate the process we are going to take 8, 9, 10 as outputs
  // - 8 will be the data
  // - 9 will be the clock
  // - 10 will be the latch
  DDRB |= 7;            //set data direction reg bit 0 to output
  PORTB &=~(7);            //set outputs low
  Serial.begin(9600); 
  Serial.println("Initializing timerinterrupt"); 
  //Timer2 Settings: Timer Prescaler /64,  using prescaler 1 --> 16000000/ 64 / 1 --> 250KHz
  TCCR2B |= (1<<CS20);     
  TCCR2B &= ~((1<<WGM22) | (1<<CS22) | (1<<CS21));      
  // Use normal mode 
  TCCR2A &= ~((1<<WGM21) | (1<<WGM20));   
  // Use external clock  
  ASSR |=  (1<<AS2) | (1<<EXCLK); 
  //Timer2 Overflow Interrupt Enable 
  TIMSK2 |= (1<<TOIE2) | (0<<OCIE2A);   
  RESET_TIMER2;                
  sei(); 
  starttime = millis(); 
}

void loop() {
  if (oldSecond != second) { 
    //Serial.print(second); 
    //Serial.print(". ->"); 
    //Serial.print(millis() - starttime); 
    //Serial.println("."); 
    //Serial.print("tendency "); 
    //Serial.print(tendency,DEC); 
    //Serial.print(" - cont - "); 
    //Serial.println(cont); 
    if(tendency) fadein(cont);
    else fadeout(cont);

    oldSecond = second; 
    cont++;
    if(cont > numPWMs) {
      cont = 1;

      // checking if lamps are still fading
      int fadelevel = 0;
      for(int i = 0; i < numPWMs; i++)
        if (flags[i]>0 && flags[i]<=2) fadelevel = flags[i];
      if(fadelevel==0) {
        tendency ^= B1;
    //Serial.println(fadelevel,DEC); 
      }
    }
  } 
}