/*****************************************
Program for 7segment voltmeter
Program written by MKDas, email: mithun060@gmail.com;
MCU: PIC16F73B, X-Tal: 8MHz (external).
************************************************/
unsigned int adc_rd0,tlong;
unsigned short mask(int num)
{
 switch (num)
 {
   case 0 : return 0xC0;
   case 1 : return 0xF9;
   case 2 : return 0xA4;
   case 3 : return 0xB0;
   case 4 : return 0x99;
   case 5 : return 0x92;
   case 6 : return 0x82;
   case 7 : return 0xD8;
   case 8 : return 0x80;
   case 9 : return 0x90;
   case 10: return 0x40;
   case 11: return 0x79;
   case 12: return 0x24;
   case 13: return 0x30;
   case 14: return 0x19;
   case 15: return 0x12;
   case 16: return 0x02;
   case 17: return 0x78;
   case 18: return 0x00;
   case 19: return 0x10;
 }
}

unsigned short shifter, portb_index;
unsigned int digit, number;
unsigned short portb_array[4];

void interrupt()
{
  PORTC = 0;
  PORTB = portb_array[portb_index];
  PORTC = shifter;


  shifter <<= 1;
  if(shifter > 8u)
  shifter = 1;


  portb_index ++ ;
  if (portb_index > 3u)
  portb_index = 0;
  TMR0 = 0;
  INTCON = 0x20;
 }
 void display()
 {
   digit = number % 10u;
   portb_array[0] = mask(digit);
   digit = (number / 10u) % 10u;
   portb_array[1] = mask(digit);
   digit = (number / 100u) % 10u+10;
   portb_array[2] = mask(digit);
   digit = number / 1000u;
   portb_array[3] = mask(digit);
 }

void main()
{
  // port initialization...
  TRISB = 0x00; // Set PORTB direction to be output
  PORTB = 0xff;    // Turn OFF LEDs on PORTB
  TRISC= 0x00; // Set PORTB direction to be output
  PORTC = 0x00;
  TRISA = 0xFF; // all input

 digit = 0;
 portb_index = 0;
 shifter = 1; 
 number = 0;                          //initial value;
 

 ADCON1 = 0x00;
 // tiemr0 settings...
 OPTION_REG = 0x80;                   // Set timer TMR0;
 TMR0 = 0;
 INTCON = 0xA0;                       // Disable interrupt PEIE,INTE,RBIE,T0IE
 
 

 while(1)
  {
    // Read Battery  voltage
    ADCON0 = 0b00000001;
    adc_rd0 = ADC_Read(0);        // A/D conversion. Pin RA2 is an input.
    tlong = (float)adc_rd0 *1.96078431372549; // Convert the result in millivolts
    number = tlong;
    display();
  }//Endless loop;
}//End.