// Final Project -- Disco Light
// Alex Cerruti and Chris Wherry

#include <90s8515.h>
#include <delay.h>

//timeout values for each task
#define t1 25  
#define t2 50

unsigned char reload;			  //timer 0 reload to set 2 mSec
unsigned char time1, delay;		  //timeout counters, delay produces a crude debounce
unsigned char beat_flag;		  //light states
int count, color, next_color, positions;  //define variables for functions

//the three task subroutines
void task1(void);  // turns fan on and off
void cw(void);  // function to move color wheel one color clockwise
void ccw(void); // function to move color wheel one color counter-clockwise
void beat(void); // control movement of color wheel with inputted music
void initialize(void); //all the usual mcu stuff  

//**********************************************************
//timer 0 overflow ISR
interrupt [TIM0_OVF] void timer0_overflow(void)
  {
  //reload to force 1 mSec overflow
  TCNT0=reload;

  //Decrement the three times if they are not already zero
  if (time1>0)	--time1;
  }

//**********************************************************
//Entry point and task scheduler loop
void main(void)
  {
  initialize();

  //main task scheduler loop
  while(1)
    {
      if (time1==0)   task1();
      if (PIND.6==0 & beat_flag==0) // we detect a beat
      {                             // set flag so we only change one color per beat
    		beat_flag=1;        // we have reached a beat call beat() function
    		beat();             // call beat and change color 
    		delay=t2;                   
      }
      
      if (PIND.6==1 & --delay==0)
      { 
        delay = t2;
      	beat_flag=0;   // no more bass beat ready for a new beat
      }
          
    }
  }
//**********************************************************
//Temperature turn on fan function
void task1(void)
{
	time1 = t1; 
	if(PIND.7 == 1)          //turn off the fan in this case
	{  
		PORTC = 0xf0;    // keep halogen on, but turn off fan
	}
	else		         //otherwise turn it on
		PORTC = 0xff;
}


//**********************************************************
// Function that moves it counter-clockwise 
void ccw(void)
{
    //make motor step forward twenty steps
    for(count=0; count<5*positions; count++)
    {
	PORTB = 0x01;
        delay_ms(5);
	PORTB = 0x02;
        delay_ms(5);
	PORTB = 0x04;
        delay_ms(5);
	PORTB = 0x08;
        delay_ms(5);
    }        
}


//**********************************************************
// Function that moves it clockwise 
void cw(void)
{
   //make motor step backward twenty steps
   
   for(count=0; count<5*positions; count++)
   {
    	PORTB = 0x08;
        delay_ms(5);
	PORTB = 0x04;
        delay_ms(5);
	PORTB = 0x02;
        delay_ms(5);
	PORTB = 0x01;
        delay_ms(5);
    }                  
}

///////////////////////////////
// Color Table:
// 0 - black
// 1 - white
// 2 - light green
// 3 - blue
// 4 - yellow
// 5 - orange
// 6 - green
// 7 - amber
// 8 - pink
// 9 - magenta
// 10 - strobe
////////////////////////////////

void beat(void)
{
  
  next_color = TCNT0 % 11;          // get a random number between 0 and 10
  
  if (next_color == 10)   // if strobe
  {
       next_color=1;   // first set to white     
       
       // move to white from current color
       if (next_color-color>0)
       {
           positions = next_color-color;  // calculate number of positions needed to turn
           ccw();
           color = next_color;            // keep track of new color
       }
  
       if (next_color-color<0)
       {
           positions = color-next_color;  // make sure positions is positive
           cw(); 
           color = next_color;            // keep track of new color
       }

       // now oscillate between black and white for 5 times
       positions=1;
       for(count=0; count<5; count++)
       {
          cw();  // now on black
          ccw();   // now on white
       }
  }
  
  else if (next_color-color>0)
  {                    
     positions = next_color-color;  // calculate number of positions needed to turn
     ccw();
     color = next_color;            // keep track of new color
  }

  else if (next_color-color<0)
  {
     positions = color-next_color;  // make sure positions is positive
     cw(); 
     color = next_color;            // keep track of new color
  }
}

//**********************************************************
//Set it all up
void initialize(void)
{
//set up the ports
  DDRD=0x00;	//PORT D in an input
  DDRB=0xff;    //PORT B is an output
  DDRC =0xff;   //PORT C is an output
  PORTB=0x00;  	//initialize PortB to 0
  PORTC=0xf0;   //intialize PortC to f0 (turn on light/fan off)

// For 8515:
//  UCR = 0x10 + 0x08 ;
//  UBRR = 51 ; //using a 8 MHz crystal

  reload=256-125; 	//value for 1 msec for 8 MHz
  TCNT0=reload;
  TIMSK=2;		//turn on timer 0 overflow ISR (Mega pg. 30)
  TCCR0=3;		//prescalar to 64

  //init the task timers
  time1=t1;

  //make motor to reset position
  // color will then be black
  for(count=0; count<52; count++)
  {
  PORTB = 0x08;
     delay_ms(5);
  PORTB = 0x04;
     delay_ms(5);
  PORTB = 0x02;
     delay_ms(5);
  PORTB = 0x01;
     delay_ms(5);
  }
  
  beat_flag = 0;  // intialize beat flag to zero (received no base beats yet)
  color = 0;   // black
  next_color = 0; // initalize
  positions = 0; // how many positions to turn            
  delay = t2;            
  //crank up the ISRs
  #asm
  	sei
  #endasm
}