PIC16f877a comparator module

[sarge]

Hi, i have some problems with comparator in PIC16f877a

My code

#include <htc.h>
#include <stdio.h>

#define _XTAL_FREQ 4000000

__CONFIG(WDTDIS & UNPROTECT & LVPDIS & HS & BOREN);

void main()
{
    CMCON = 0x02;
    ADCON0 = 0xFF;
    ADCON1 = 0xFF;
    TRISB1 = 0;
    TRISB2 = 0;
    TRISA0 = 1;
    TRISA3 = 1;
    RB1 = 0;
    RB2 = 1;


    GIE = 1;
    PEIE = 1;
    CMIE = 1;

    while(1)
    {
        
    }

}

void interrupt isr()
{
    if (CMIF)
    {
        RB2 = !RB2;
        CMCON = 0x02;
        CMIF = 0;
    }
}

This code works fine in proteus, but doesn't work in hardware. What is wrong here?
Compiler - Hi-tech PICC 9.71.
Thanks for advance.