gistfile1.txt

#include <18F4520.h>
#use delay (clock = 20000000)
#fuses HS, NOWDT, NOLVP
#include "../4520_B.h"
#include "../modifiedlcd_B.h"


#define COL0 0x6
#define COL1 0x5
#define COL2 0x3
#define ROW0 0xE
#define ROW1 0xD
#define ROW2 0xB
#define ROW3 0x7



unsigned int16 *AD=0xFC3;                   //right justified
float Vres = 5.0/1023.0;
float voltage;

#INT_AD
void int_ad_isr(){
voltage = (Vres *(float)(*AD))/5*100;
}


struct _KeyPad{
   int columns:3;
   int unused:1;
   int rows:4;};
struct _KeyPad *KEYPAD = 0xF81;

char KeyPadPress(void);
int twoDigitNumber(currentValue);
int16 currentValue;

main(){
   lcd_init();
   *TRISA = 0x01;                         //A0 input
   *ADCON0 = (*ADCON0 | 0x01) & 0x03;     //ch0, AD-ON
   *ADCON1 =0x0E;                         //from modifiedlcd.h
   *ADCON2 |= 0x80;                       //right justified, 16 TAD, FOSC/2
   *TRISB = 0xF0;                         //B7-B4 input
   INTCON2->RBPU = 0;                     //pullups ON
   *PIE1 |= 0x40;                         //A/D int enable
   while(1){
      *ADCON2 = 0x02;
      currentValue = twoDigitNumber(currentValue);
      printf(lcd_putc,"\f %lu",currentValue);
      printf(lcd_putc, "\n Vin =%f", (Voltage));
      delay_ms(200);
   }
}
//function declaration
char KeyPadPress(void){
   char x='_'; //default
   KEYPAD->columns = COL0;
   switch(KEYPAD->rows){
      case ROW0:
         x ='1';
         break;
      case ROW1:
         x='4';
         break;
      case ROW2:
         x='7';
         break;
      case ROW3:
         x='*';
         break;
      default:
   }
   KEYPAD->columns = COL1;
   switch(KEYPAD->rows){
      case ROW0:
         x ='2';
         break;
      case ROW1:
         x='5';
         break;
      case ROW2:
         x='8';
         break;
      case ROW3:
         x='0';
         break;
      default:
   }
   KEYPAD->columns = COL2;
   switch(KEYPAD->rows){
      case ROW0:
         x ='3';
         break;
      case ROW1:
         x='6';
         break;
      case ROW2:
         x='9';
         break;
      case ROW3:
         x='#';
         break;
      default:
       }
    return(x);
   }
  int twoDigitNumber(int currentValue){
    int numericValue;
    numericValue = (int)keyPadPress()-0x30;
    if(numericValue<=9 && numericValue>=0){
       if( currentValue>10 && currentValue < 100){
          currentValue=0;
       }
       currentValue = currentValue*10+numericValue;
    }
    return(currentValue);
}