CODE OF PIC 16F877A FOR MAKING DVM USING MICRO C PROGRAMMING IDE

NOTE:  This is the programming code written for pic 16877 for making digital voltmeter.The IDE used for this program is micro c programming.we should also know that this code is written in C language whereas pic doesnot understand C,it only knows the Hex code so it must be first converted to hex code and then it is burned to the pic.

The design is performed in proteus

all the  things within /.........../ are the comments.




/*************display in LCD using 8-bit, 2 line mode*******/
#include <htc.h>

#define data PORTB
#define RS RD0
#define EN RD1
float result,val;
int val1,val2;
__CONFIG(HS & WDTDIS & PWRTEN & BORDIS & LVPDIS);

void delay_ms(int n )
{
           TMR1H=0xEC;        // EC77H=60535d
        TMR1L=0x77;
        T1CKPS1=0;
        T1CKPS0=0;
        TMR1CS=0;
        TMR1IF=0;
        TMR1ON=1;
           while(n>0)
           {
                while(!TMR1IF)  { }
                TMR1IF=0;
                TMR1H=0xEC;
                TMR1L=0x77;
                n--;
        }
}
void delay_100us(int n )      
{
           TMR1H=0xFE;      
        TMR1L=0x0C;
        T1CKPS1=0;
        T1CKPS0=0;
        TMR1CS=0;
        TMR1IF=0;
        TMR1ON=1;
           while(n>0)
           {
                while(!TMR1IF)  { }
                TMR1IF=0;
                TMR1H=0xFE;      
                TMR1L=0x0C;
                n--;
        }
}


void LCD_Write(unsigned char value,int rs)
{
        data = value;
        RS = rs;                                //if rs=0; command is sent to LCD otherwise data to be displayed is sent
        EN = 1;
        delay_ms(1);
        EN = 0;

}

void LCD_clear(void)
{
        LCD_Write(0x01,0);                //this clears LCD
}

void LCD_goto(unsigned char row,unsigned char column)
{
        if(row==1){
                LCD_Write(0x80+column,0);        //
        }
        else if(row==2){
                LCD_Write(0xC0+column,0);
        }


}
void LCD_num(int n)
{

    if(n<=9)
    {
            LCD_Write(48+n,1);
         }
         else if(n<=99)
         {
                 LCD_Write((n/10)+48,1);
                 LCD_Write((n%10)+48,1);
        }
        else if(n<=999)
        {
                LCD_Write((n/100)+48,1);
                LCD_Write(((n%10)/10)+48,1);
                LCD_Write((n%10)%10+48,1);
        }
}
void init_ADC()
{
        PCFG3=0;        PCFG2=0;  PCFG2=0;  PCFG0=0;                //Configures all the pins of PORTA and PORTB as ANALOG pins.

        /*For correct A/D conversions, the A/D conversion clock must be selected to ensure a minimum
        TAD time of 1.6 ms as shown in parameter 130 of the “Electrical Specifications” section.*/

        ADCS1=1;        ADCS0=0;        //this gives  32*Tosc=1.6 us
        ADFM=1;                                //Left justified format viz 6 LSBs of ADRESL regsiter are read as ‘0’.
        //Result will be held at ADRESH and ADRESL register
}
void initLCD(void)
{
        //PORT configuration
        TRISB = 0x00;
        TRISD=0x00;
        //////////////////

        LCD_Write(0x30,0);
//        data = 0x3;         // 8 bit mode
        EN=1; EN = 0;
        LCD_Write(0x38,0);
        delay_ms(1);
        LCD_Write(0x0C,0);    //dispaly on , no cursor blinking
        delay_ms(1);
        LCD_Write(0x01,0);    // clear dispaly screen


        delay_ms(1);
        LCD_Write(0x06,0);
        delay_ms(1);
        LCD_clear();
        LCD_goto(1,1);
        LCD_goto(1,1);        //1st row 1st column
    LCD_Write('D',1);delay_ms(100); LCD_Write('I',1);delay_ms(100); LCD_Write('G',1);delay_ms(100); LCD_Write('I',1);delay_ms(100);
        LCD_Write('T',1);delay_ms(100);LCD_Write('A',1);delay_ms(100);LCD_Write('L',1);delay_ms(100);LCD_Write(' ',1);delay_ms(100);
        LCD_Write('V',1);delay_ms(100);LCD_Write(' ',1);delay_ms(100);LCD_Write('M',1);delay_ms(100);LCD_Write('E',1);delay_ms(100);
    LCD_Write('T',1);delay_ms(100); LCD_Write('E',1);delay_ms(100); LCD_Write('R',1);
        LCD_goto(2,1);
    LCD_Write('D',1);  LCD_Write('C',1);  LCD_Write(' ',1);  LCD_Write('V',1);  LCD_Write('O',1);  LCD_Write('L',1);  LCD_Write('T',1);  LCD_Write('=',1);

}
/************Analog to digital conversion will occur here**********/
void ADC()
{
        ADON=1;                                         //A/D converter module is powered up
        /**********************channel one********************/
        CHS2=0; CHS1=0; CHS0=0;        // selecting pin A0 as input pin where analog signal will appear
        delay_ms(3);
    ADGO  = 1;                                         //ADGO WILL BE  RESET  BY  SYSTEM AUTOMATICALLY ONCE   ADC   IS   COMPLETE
        while(ADGO);
    result=(ADRESH<<8)+ADRESL;
    LCD_goto(2,9);
    if(result<511||result>512)
     {
         if(result>512.0)
           {//        LCD_goto(2,9);
            LCD_Write(' ',1);
             result=result-511.5;
   
        }
        else if(result<511.0)
         {//LCD_goto(2,9);
          LCD_Write('-',1);   //displaying negative sign
          result=result-511.5;
           result=-(result);
       }
       result=result*30/511.5;
       val1=(int)result;
       LCD_num(val1);
       LCD_Write('.',1);   //displaying dot sign
       val=result-val1;
       val=val*1000;
       val2=(int)(val);
       LCD_num(val2);
}
  else
    {result=0;
     LCD_Write(' ',1);
     LCD_Write(' ',1);
     result=result*30/511.5;
     val1=(int)result;
     LCD_num(val1);
     LCD_Write('.',1);   //displaying dot sign
     val=result-val1;
     val=val*1000;
     val2=(int)(val);
     LCD_num(val2);}



}

void main(void)
{        TRISB=0x00;                //Configuring all pins of B port as output.
        PORTB=0x00;                //output at all pins will be low
        TRISA=0xff;                        //Configuring all pins of A port as input
        TRISD0=TRISD1=0;
        RD0=RD1=0;
        initLCD();
        init_ADC();
while(1)
 {
        ADC();                //call ADC convert
}
}