//VR1.C
//#include <16F628.h>
#include <16F648A.h>
#use delay(clock=4000000)
#define  TxD         PIN_A0   
#define  RxD         PIN_A1   
#use rs232(baud=9600, xmit=TxD,rcv=RxD) 
#fuses XT,PUT,BROWNOUT,MCLR,NOWDT,NOPROTECT,NOLVP

#byte	TRISA   = 0x85 
#bit    PINVR1 = TRISA.3

void ReadVR(void)
{
long Cn=0;

 PINVR1=0;                          //Set Port to Output
 output_bit(PIN_A3,0);              //Output bit = 0
 delay_us(25);                      //Delay for charge C
 PINVR1=1;                          //Set Port to Input
 while(input(PIN_A3)==0)            //Read Port
  Cn++;                             //Count if still 0
 
 printf("%lu\r\n",Cn);
}
void main(void) 
{
long Cn;

   set_tris_a(0B11111110);
   set_tris_b(0B01111110);

   printf("*** Test VR1 ***\r\n");

//Read Key
   while(1)
   {
    if(input(PIN_A2)==0)            //Key press
    {
      delay_ms(100);                //Delay and read again
      if(input(PIN_A2)==0)          //if Key still press
      {
       while(input(PIN_A2)==0);     //wait for release
        ReadVR();
      }
    }

   }
}