POV/BCD Clock

POV(persistence of vision)/BCD(binary coded decimal) Clock


*POV mode:

*BCD mode:



source code for PIC16F microcontroller:

 /////////////////////////////////////////////////////  
 // Persistence Of Vision (POV) clock  
 // Binary Coded Decimal (BCD) clock  
 // Hi-Tech C code by YUS of ElectronicsLab.Ph  
 // revision 2.1 Nov 24, 2008  
 /////////////////////////////////////////////////////  
   
 #include <htc.h>  
 #define _XTAL_FREQ 32768  
 __CONFIG(XT & WDTDIS & PWRTEN & BORDIS & DUNPROT & WRTEN & UNPROTECT);  
   
 #define leds               PORTC  
 #define leds_tris()          TRISC = 0x00;  
 #define adjust               RB7  
 #define adjust_minutes     RB6  
 #define adjust_hours     RB5  
   
 const unsigned char digits[10][5]={ //10 digits, 5 bytes each  
   0xc1,0xae,0xb6,0xba,0xc1,  // 0  
   0xff,0xbd,0x80,0xbf,0xff,  // 1  
   0xbd,0x9e,0xae,0xb6,0xb9,  // 2  
   0xde,0xbe,0xba,0xb4,0xce,  // 3  
   0xe7,0xeb,0xed,0x80,0xef,  // 4  
   0xd8,0xba,0xba,0xba,0xc6,  // 5  
   0xc3,0xb5,0xb6,0xb6,0xcf,  // 6  
   0xfe,0x8e,0xf6,0xfa,0xfc,  // 7  
   0xc9,0xb6,0xb6,0xb6,0xc9,  // 8  
   0xf9,0xb6,0xb6,0xd6,0xe1,}; // 9  
 /*    
 const unsigned char am_pm[2][11]={  
   0x81,0xee,0xee,0xee,0x81,0xff,0x80,0xfd,0xf3,0xfd,0x80,  // AM  
   0x80,0xf6,0xf6,0xf6,0xf9,0xff,0x80,0xf6,0xf6,0xf6,0xf9,}; // PM  
 */    
 unsigned char hours, minutes, seconds;  
 //unsigned char hours_tens, hours_ones, minutes_tens, minutes_ones;  
     
 // Interrupt Handler  
 void interrupt isr()  
 {  
      // Timer0 Interrupt - Freq = 0.50 Hz - Period = 2.000000 seconds  
      if (TMR0IF) // timer 0 interrupt flag  
      {  
           TMR0IF = 0;     // clear the flag  
        seconds += 2; //increment time  
      }  
 }  
 void initialize(void)  
 {  
      //initial time  
      hours = 12;  
      minutes = 34;  
      seconds = 0;    
   
      //Timer0 Registers Prescaler= 64 - TMR0 Preset = 0 - Freq = 0.50 Hz - Period = 2.000000 seconds  
      T0CS = 0; // bit 5 TMR0 Clock Source Select bit...0 = Internal Clock (CLKO) 1 = Transition on T0CKI pin  
      T0SE = 0; // bit 4 TMR0 Source Edge Select bit 0 = low/high 1 = high/low  
      PSA = 0;  // bit 3 Prescaler Assignment bit...0 = Prescaler is assigned to the Timer0  
      PS2 = 1;  // bits 2-0 PS2:PS0: Prescaler Rate Select bits  
      PS1 = 0;  
      PS0 = 1;  
      TMR0 = 0;       // preset for timer register  
   
      // Interrupt Registers  
      INTCON = 0;      // clear the interrpt control register  
      TMR0IE = 1;    // bit5 TMR0 Overflow Interrupt Enable bit...1 = Enables the TMR0 interrupt  
      TMR0IF = 0;    // bit2 clear timer 0 interrupt flag  
      GIE = 1;      // bit7 global interrupt enable  
   
      leds_tris();  
      RBPU = 0;     //enable portB internal pullups  
 }  
 void leds_on(unsigned char char_byte) //0xff = all LEDs off; 0x00 = all LEDs on  
 {  
      leds = char_byte;     // use port C for LEDs  
      NOP();  
 }  
 void check_time(void)  
 {  
   if (seconds >= 60) { seconds-=60; minutes+=1; }  
   if (minutes >= 60) { minutes-=60; hours+=1; }  
   if (hours > 12) { hours -=12; } //12-hour format  
   //if (hours > 24) { hours -=24; } //24-hour format  
 }  
 void pov_display(void) // persistence of vision (POV) mode  
 {  
      unsigned char i, digit, hours_tens[5], hours_ones[5], minutes_tens[5], minutes_ones[5];  
      digit = hours/10;  
      for(i=0; i<5; i++) hours_tens[i]= digits[digit][i];   
      digit = hours%10;  
      for(i=0; i<5; i++) hours_ones[i]= digits[digit][i];   
      digit = minutes/10;  
      for(i=0; i<5; i++) minutes_tens[i]= digits[digit][i];   
      digit = minutes%10;  
      for(i=0; i<5; i++) minutes_ones[i]= digits[digit][i];  
      if ((hours/10)!=0)  //'wag ng i-display kung wala naman  
      {  
           // hours' tens digit  
           leds_on(hours_tens[0]);  
           leds_on(hours_tens[1]);  
           leds_on(hours_tens[2]);  
           leds_on(hours_tens[3]);  
           leds_on(hours_tens[4]);  
      }  
      // hours' ones digit  
      leds_on(hours_ones[0]);  
      leds_on(hours_ones[1]);  
      leds_on(hours_ones[2]);  
      leds_on(hours_ones[3]);  
      leds_on(hours_ones[4]);  
      leds_on(0xff);  
      _delay(5);  
      // colon  
      leds_on(0xc9);  
      _delay(5);  
      leds_on(0xff);  
      // minutes' tens digit  
      leds_on(minutes_tens[0]);  
      leds_on(minutes_tens[1]);  
      leds_on(minutes_tens[2]);  
      leds_on(minutes_tens[3]);  
      leds_on(minutes_tens[4]);    
      leds_on(0xff);  
      _delay(2);    
   // minutes' ones digit  
      leds_on(minutes_ones[0]);  
      leds_on(minutes_ones[1]);  
      leds_on(minutes_ones[2]);  
      leds_on(minutes_ones[3]);  
      leds_on(minutes_ones[4]);  
      leds_on(0xff);  
 }  
 void binary_display(void) //binary coded decimal (BCD) mode  
 {  
      leds_on(~( ( (hours/10)<<4) + (hours%10) ) ); // BCD hours  
      __delay_ms(1000);  
      leds_on(0xff);  
      __delay_ms(200);  
      leds_on(~( ( (minutes/10)<<4) + (minutes%10) ) );  //BCD minutes  
      __delay_ms(1000);  
      leds_on(0xff);  
      __delay_ms(500);  
 }  
 void adjust_time(void)  
 {  
   TMR0IE = 0;     //disable timer0interrupt  
   while( adjust_hours && adjust_minutes ) binary_display();  
   while(!adjust)  
   {  
    // with BCD display  
    if(!adjust_minutes)  
    {  
      minutes+=1;  
      check_time();  
      leds_on(~( ( (minutes/10)<<4) + (minutes%10) ) );  //BCD minutes  
      __delay_ms(500);  
    }  
    if(!adjust_hours)  
    {  
      hours+=1;  
      check_time();  
      leds_on(~( ( (hours/10)<<4) + (hours%10) ) ); // BCD hours  
      __delay_ms(500);  
    }  
   }    
      TMR0IE = 1;     //enable timer0 interrupt  
 }  
 void main()  
 {  
      initialize();  
      while(1)  
      {  
           check_time();  
           if(!adjust) adjust_time();  
           //choose either pov or binary mode  
           pov_display();     __delay_ms(200);  
           //binary_display();     __delay_ms(200);  
      }          
 }