hi ! & thanks for your help. i have a 12c508jw & have tried to read the osscal value prior to programming it. i can't find the osscal code when i read the pic when using picprog. it just shows all F's since i'll have to install a calibration constant at the beginning of the program (because its a 12c508jw) is this the correct way org 0x00 movlw cc ;cc = calibration constant movwf osccal thanks for your assistance , i appreciate it glen