pic16f1829 not work

[smxmarco]

hello i need help :
pic 16f1829 does not work,
which sets for portA4=AN3 ?
I turn on all the doors but it doesn't work!
Are the sets correct?
Thanks so much

main: 'RA4 analogico
INTCON = 0 ' Disable PEIE,INTE,RBIE,T0IE
ADCON0 = %00001101 'definisce i canali convertitore A/D + abilita(bit4)
'bit2-5 def canali a/d, 0000=ra.0=an
'ADCON1

'anselA=%00001000
anselA=%00010001

CM1CON0=0
CM2CON0=0
trisa=%00011000 'definisce porta come ingresso e uscite (0=out, 1=in )
porta=0 'azzera porta

trisb=%11000000 'defisce portb come ingresso e uscite (0=out, 1=in )
portb=0

trisc=%10000000 'defisce portc come ingresso e uscite (0=out, 1=in )
portc=0
'-----------------------------------
porta=1
portb=1
portc=1
end.

[smxmarco]

Can anyone give me some advice where am I going wrong?
thank you