hi james ,

James Cameron wrote:

> Glen wrote:
> > 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
>
> If you erased it, then this is what I would expect.  Read it before
> erasing it.  If it's too late, then bad luck.  Either buy another one,
> or ask around for the procedure to re-create it using a test jig.

****************i never programmed it. only tried to read the calibration
value & couldnt
**********

>
>
> > since i'll have to install a calibration constant at the beginning of
> > the program (because its a 12c508jw) is this the correct way?
>
> No.  It should go at the last code location as described in the data
> sheets.  The instruction should be the "movlw" there, and the "movwf"
> should be at 0x00.

****************i read from the microcontroller handbook (2-28)but its
pretty vague( for a beginner that is )sorry but to clarify your statement,
you mean setup like this

--------------
config word
----------------
variables
--------------------
        ORG       0x1FF      ;
        ORG       0x000      ; this is what the template shows
        MOVWF     OSCCAL     ;
------------------------
        GOTO START            ;start of program
---------------------
  ; rest of code
----------------------
        MOVLW    CC    ;CC = calibration value (2ND last piece of code)
        end            ;end of code

with thanks , glen