ISIS PWM 16F877 problem ?

//#include "speed control.h"
#include <16F877.h>
#device adc=8

#FUSES NOWDT                    //No Watch Dog Timer
#FUSES HS                       //High speed Osc (> 4mhz for PCM/PCH) (>10mhz for PCD)
#FUSES NOPUT                    //No Power Up Timer
#FUSES NOPROTECT                //Code not protected from reading
#FUSES NOBROWNOUT               //No brownout reset
#FUSES NOLVP                    //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOCPD                    //No EE protection
#FUSES NOWRT                    //Program memory not write protected
#FUSES NODEBUG                  //No Debug mode for ICD

#use delay(clock=20000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#use rs232(baud=9600,parity=N,xmit=PIN_D0,rcv=PIN_D1,bits=8,stream=DEBUG)

#define Delay 1

#int_RDA
void  RDA_isr(void) 
{

}



void main()
{
   char com,spd,pos,val;
   signed int16 diff;
   setup_adc_ports(AN0_AN1_AN3);
   setup_adc(ADC_CLOCK_DIV_32);
   setup_psp(PSP_DISABLED);
   setup_spi(SPI_SS_DISABLED);
   setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
   setup_timer_1(T1_DISABLED);
   enable_interrupts(INT_RDA);
   enable_interrupts(GLOBAL);
   setup_timer_2(T2_DIV_BY_16,255,1);
   setup_ccp1(CCP_PWM);
   set_pwm1_duty(50);
   // TODO: USER CODE!!
   while(1){
      set_adc_channel(1);
      delay_ms(Delay);
      com = read_adc();
      delay_ms(Delay);
      set_adc_channel(0);
      delay_ms(Delay);
      spd = read_adc();
      diff = com - spd;
      if(com > spd){pos='+';val=diff;}
      else{pos='-';val=~diff;}
      fprintf(DEBUG,"%c",pos);
      fprintf(DEBUG,"%u\r",val);
      delay_ms(Delay);
      delay_ms(300);
   }

}