what do i do wrong?

i'm trying to do a 1750Hz tone générator on 12c508a and it doesn't work so i reduce the code and test it on 12f683 (with the right fuse!) and it run ok so i test it on 12f508 it doesn't run too.
here are the two test code, i don't understand what i'm doing wrong.

code for 12f508 that doesn't work

Code:

---


@ device  pic12F508, INTRC_OSC, MCLR_OFF,WDT_OFF,PROTECT_OFF

GPIO = %00000000        ' toutes les sorties = low
'CMCON0 = 7              ' Comparateur en mode 'comparator off'
TRISIO = %00001000      ' GP0 à GP5 en sortie sauf GP3
'ANSEL = %00000000      ' entrée analogique off
'WPU = %00000000        ' Pull-ups off
OPTION_REG.6 = 0        ' disable internal pull-ups


'----------------------------------------------------------------
'  Déclaration des variables
'----------------------------------------------------------------
       
       
'----------------------------------------------------------------
'  Déclaration des E/S
'----------------------------------------------------------------

        SORTIE      var gpio.2
        output sortie       
'----------------------------------------------------------------
'  Initialisation
'----------------------------------------------------------------

        low sortie
       
'----------------------------------------------------------------
'  Début de programme
'----------------------------------------------------------------

DEBUT:

    high sortie
    pauseus 286
    low sortie
    pauseus 286
    goto debut

---

code for 12f683 that work well

Code:

---


@ device pic12f683, fcmen_off, ieso_off, intrc_osc, wdt_off
@ device pic12f683, pwrt_on, mclr_off, protect_off


GPIO = %00000000        ' toutes les sorties = low
CMCON0 = 7              ' Comparateur en mode 'comparator off'
TRISIO = %00001000      ' GP0 à GP5 en sortie sauf GP3
ANSEL = %00000000      ' entrée analogique off
WPU = %00000000        ' Pull-ups off
OPTION_REG.7 = 1        ' Disable internal pull-ups


'----------------------------------------------------------------
'  Déclaration des variables
'----------------------------------------------------------------
       
       
'----------------------------------------------------------------
'  Déclaration des E/S
'----------------------------------------------------------------

        SORTIE      var gpio.2
       
'----------------------------------------------------------------
'  Initialisation
'----------------------------------------------------------------

        low sortie
       
'----------------------------------------------------------------
'  Début de programme
'----------------------------------------------------------------

DEBUT:

    high sortie
    pauseus 286
    low sortie
    pauseus 286
    goto debut

---

i use 'pauseus' instead of 'freqout' because 'freqout' doesn't work on 12Cxx

can someone help me?

Add this line at the top of your 12F508 code, before the TRIS line.

Code:

---

OPTION_REG.5=0

---

it work fine now!

thanks a lot

merci beaucoup et bonjour de france