gistfile1.txt

#include <18f4520.h>
#use delay(clock=20000000)
#fuses HS, NOWDT, NOLVP
#include "../Library/18f4520ptr.h"
#include "../Library/KeypadC1.h"
#include "../Library/modifiedlcd.h"

float Vres=5.0/1023.0;
float Voltage, Voltage1;
float Vmin=0;

#INT_AD
void int_ad_isr(){
   Voltage=*Q*Vres-Vmin;
}

main(){
   int16 press1, press2, VoltagePer;
   lcd_init();  
   ADCON0->ADON=1;   //Turn on A/D conversion
   ADCON0->CHSx=0;   //Turn Channel 0 A/D on
   ADCON1->PCFGx=0x0F;  //Set port A all channels to Digital 
   *TRISA=0x0F;   // Port A, 4 LSB input
   *TRISB=0xF0;   // Port B, 4 LSB output, 4 MSB input.
   *TRISC=0x00;   // Port C output.
   ADCON2->ADFM=1;   //RJ
   //Enable References
   ADCON1->VCFG0=1;  // Enables -Voltage reference, used in A/D conversion. Allows usage of voltages lower then zero.
   ADCON1->VCFG1=1;  // Enables +Voltage reference, used in A/D Conversion.
   //Interupt Setup
   PIE1->ADIE=1;  // Enables A/D external interupt.
   INTCON->GIE=1; // Because RCON->IPEN=0 INTCON->GIE=1 enables all unmasked intrrupts.  
   INTCON->PEIE=1;   // Enables all unmasked peripherial interrupts. 
   INTCON2->RBPU=0;  // PortB Pull up resistors are enabled
   while(1){
      press1=(int16)KeyPress()-0x30;  //Takes the ASCII value from the keypress and removes the hex value.
      Voltage1=((Voltage/5)*100);   // Converts voltage from pot to a % value.
      if(press1<=9 && press1>=0){   // Filters out any value other than 0-9
         press2=((press2*10)+press1);  // Takes the first press, saves it for use when adding press1 to press2
         if(press2>100){   // if the press2 value is greater than 100 reset press2 to 0 value.
            press2=0;
         }
      }
      printf(lcd_putc,"\f %2.0f", (Voltage1-press2));  // print the difference of %voltage and press2
      printf(lcd_putc,"\n %1.2fV  %lu", Voltage, press2);   //Print Pot voltage, print keypad value.
      ADCON0->GODONE=1;    //Go preform A/D conversion
      delay_ms(300);
   }
}