/* Lab 03 - Cronometro digital programable
Laboratorio de sistemas digitales y microprocesadores
Nomar Sánchez, ID: 1104168*/

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

volatile uint8_t display1_data;
volatile uint8_t BUTTON=5;

uint8_t n1 = 0, n2 = 0, n3 = 0, n4 = 0;
uint16_t num1 = 0, num2 = 1, suma = 0;

int Status=0;
int Reset=1, Pause=0,  Add=0, Subtract=0, Increase=0, Set=0 ;
int Number=0, Digit=0;


void Decoder0(uint8_t num) {
    switch (num) {
        case 0:
            display1_data = 0x01;
            break;
        case 1:
            display1_data = 0x4F;
            break;
        case 2:
            display1_data = 0x12;
            break;
        case 3:
            display1_data = 0x06;
            break;
        case 4:
            display1_data = 0x4C;
            break;
        case 5:
            display1_data = 0x24;
            break;
        case 6:
            display1_data = 0x20;
            break;
        case 7:
            display1_data = 0x0F;
            break;
        case 8:
            display1_data = 0x00;
            break;
        case 9:
            display1_data = 0x0C;
            break;
        default:
            display1_data = 0xFF;  // Invalid number, display nothing
            break;
    }
}

void Multiplexacion_Displays() {
    // Display 1
    Decoder0(n4);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD |= (1 << PORTD7);
    PORTB = 0x01;
    Delay1ms();

    // Display 2
    Decoder0(n3);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD |= (0 << PORTD7);
    PORTB = 0x02;
    Delay1ms();

    // Display 3
    Decoder0(n2);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD |= (1 << PORTD7);
    PORTB = 0x04;
    Delay1ms();

    // Display 4
    Decoder0(n1);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD |= (1 << PORTD7);
    PORTB = 0x08;
    Delay1ms();
    
}

void Delay500ms() {
    // Initialize Timer1
    TCCR1A = 0x00;
    TCCR1B = (1 << CS10) | (1 << CS12); // Prescaler = 1024
    TCNT1 = 65535 - 7812;  // Count for 0.1 second

    while ((TIFR1 & (1 << TOV1)) == 0); // Wait for overflow
    TIFR1 |= (1 << TOV1); // Clear the overflow flag
    TCCR1B = 0x00; // Stop the timer
}

void Delay100ms() {
    // Initialize Timer1
    TCCR1A = 0x00;
    TCCR1B = (1 << CS10) | (1 << CS12); // Prescaler = 1024
    TCNT1 = 65535 - 1563;  // Count for 2 ms

    while ((TIFR1 & (1 << TOV1)) == 0) // Wait for overflow
    {
      Multiplexacion_Displays();
    }
    TIFR1 |= (1 << TOV1); // Clear the overflow flag
    TCCR1B = 0x00; // Stop the timer
}

void Delay16ms() {
    // Initialize Timer0
    TCCR0A = 0x00;
    TCCR0B = (1 << CS00) | (1 << CS02); // Prescaler = 64
    TCNT0 = 256 - 250;  // Count for 3 ms

    while ((TIFR0 & (1 << TOV0)) == 0); // Wait for overflow
    TIFR0 |= (1 << TOV0); // Clear the overflow flag
    TCCR0B = 0x00; // Stop the timer
}

void Delay4ms() {
    // Initialize Timer0
    TCCR0A = 0x00;
    TCCR0B = (1 << CS00) | (1 << CS02); // Prescaler = 1024
    TCNT0 = 256 - 150;  // Count for 4 ms

    while ((TIFR0 & (1 << TOV0)) == 0); // Wait for overflow
    TIFR0 |= (1 << TOV0); // Clear the overflow flag
    TCCR0B = 0x00; // Stop the timer
}

void Delay1ms() {
    // Initialize Timer0
    TCCR0A = 0x00;
    TCCR0B = (1 << CS00) | (1 << CS01); // Prescaler = 64
    TCNT0 = 256 - 250;  // Count for 4 ms

    while ((TIFR0 & (1 << TOV0)) == 0); // Wait for overflow
    TIFR0 |= (1 << TOV0); // Clear the overflow flag
    TCCR0B = 0x00; // Stop the timer
}

ISR(PCINT1_vect) {
    if (PINC & (1 << PC2)) { // Button 2
      Increase=1;
      Reset=0; Pause=0;  Add=0; Subtract=0; 
      Number++;
      if (Number==10)
      {
        Number=0;
      }
    }
    
    if (PINC & (1 << PC1)) { // Button 1
      Set=1;
      Reset=0; Pause=0;  Add=0; Subtract=0; Increase=0; Number=0;
      
     if (PINC & (1 << PC1)) 
     {
       Digit++;
     }
              
     if (Digit==5)
     {
       Digit=1;
     }      
    }

    if (PINC & (1 << PC3)) 
    { // Button 3
      Reset=1;
      Pause=0;  Add=0; Subtract=0; Increase=0; Set=0; Digit=0; Number=0;
    }

    if (PINC & (1 << PC0)) { // Button 0
      Reset=0; Increase=0; Set=0; Digit=0; Number=0; Subtract=0;
            
      if (Status==0)
      {
       Add=1;
       n1 = 0, n2 = 0, n3 = 0, n4 = 0;
       num1 = 0, num2 = 1, suma = 0;
      }

      if (Status==1 or Status==3)
      {
        Pause++;
      }
      if (Pause==2)
      {
        Pause=0;
      }

      if (Status==2 or Status==3)
      {
        Subtract=1;
        num1 = 9, num2 = 1, suma = 0;
        Pause=0;  Add=0; Increase=0; Set=0; Digit=0; Number=0;
      }
    }
}

void setear_numeros()
{
  if(Digit==1)
  {
    // Display 3
    n4=Number;
    Decoder0(n4);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD |= (1 << PORTD7);
    PORTB = 0x01;
    
    Delay500ms();
    PORTB = 0x00;
    Delay500ms();   
  }  
  
  if(Digit==2)
  { 
    // Display 3
    n3=Number;
    Decoder0(n3);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD &= ~(1 << PORTD7);
    PORTB = 0x02;
   
    Delay500ms();
    PORTB = 0x00;
    Delay500ms();   
  }

  if(Digit==3)
  {  
    // Display 2
    n2=Number;
    Decoder0(n2);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD |= (1 << PORTD7);
    PORTB = 0x04;

    Delay500ms();
    PORTB = 0x00;
    Delay500ms();
  }

  if(Digit==4)
  {
    // Display 1
    n1=Number;
    Decoder0(n1);
    PORTB = 0x00;
    PORTD = display1_data;
    PORTD |= (1 << PORTD7);
    PORTB = 0x08;

    Delay500ms();
    PORTB = 0x00;
    Delay500ms();
  }
}

void Suma ()
{
  Multiplexacion_Displays();
  Delay100ms();

  // Ingreso de números (valores de 0 a 9999)
  num1 = (n1 * 1000) + (n2 * 100) + (n3 * 10) + n4;
    
  // Realizar la suma (asumiendo que también tienes valores para n1, n2, n3, y n4)
  suma = num1 + num2;

  // Descomponer la suma en n1, n2, n3 y n4
  n1 = suma / 1000;
  suma %= 1000;
  n2 = suma / 100;
  suma %= 100;
  n3 = suma / 10;
  n4 = suma % 10;
}

void Resta ()
{
  Multiplexacion_Displays();
  Delay100ms();

 // Ingreso de números (valores de 0 a 9999)
  num1 = (n1 * 1000) + (n2 * 100) + (n3 * 10) + n4;
    
  // Realizar la suma (asumiendo que también tienes valores para n1, n2, n3, y n4)
  suma = num1 - num2;

  // Descomponer la suma en n1, n2, n3 y n4
  n1 = suma / 1000;
  suma %= 1000;
  n2 = suma / 100;
  suma %= 100;
  n3 = suma / 10;
  n4 = suma % 10;  
} 

int main() {
  // Setup ports and pins
  DDRD = 0xFF; // Port D as output
  DDRB = 0xFF; // Port B as output
  DDRC = 0x00; // Port C as input

  // Enable Pin Change Interrupts on PC0, PC1, PC2, and PC3
  PCMSK1 = 0x0F;
  PCICR = (1 << PCIE1);
  sei(); // Enable global interrupts

  while (1) {
    if (Add==1)
    {
      Status=1;
      Suma();
      while (Pause==1)
      {
        Multiplexacion_Displays();
      }
      if (n1==9 and n2==9 and n3==9 and n4==9)
      {
        Reset=1;
        Add=0;
        Status=0;
      }      
    }

    if (Set==1)
    {
      Status=2;
      setear_numeros();
    }

    if (Subtract==1)
    {
      Status=3;
      Resta();
      while (Pause==1)
      {
        Multiplexacion_Displays();
      }

      if (n1==0 and n2==0 and n3==0 and n4==0)
      {
        Reset=1;
        Subtract=0;
        Status=0;
      } 
    }

    if (Reset==1)
    {
      n1 = 0, n2 = 0, n3 = 0, n4 = 0;
      num1 = 0, num2 = 0, suma = 0;
      Status=0;
      Multiplexacion_Displays();
    }
      
  }

  return 0;
}