>I have an application which uses a PIC 16C58A. After a few years of
>production, our customer would like us to make a small change in the
>operation of the device. Unfortunetly whoever my job predecessor was did
>not document any of the code, or it got lost. Anyway, I am stuck with
>trying to either recreate the application code from scratch or reading the
>code from the present device and dis-assembling it.
>
>I am able to read the code out of the device using a PICStart Plus and
>MPLAB. The code looks ok, but of course I don't have any of the meaningfull
>labels. Not a big deal since I can walk thru it and add my own labels and
>comments. HOWEVER
>I found some lines of code which don't make any sense. I got one line
>                TRIS    PORTC
>The 16C58A does not have a PORTC, so how come I got a TRIS for that port?
>
>Anyone have any hints for disassembling code from the hex file? Thanks.
>Mark Walter

Mark, does the device concerned have the code protect bit enabled ?
When CP is on, the chip scrambles the data output when read.
I've seen similar things from chips that I'd used CP on when trying to
recover code after I had a nasty HDD crash a couple of years ago !   :-(
Then again, can't say I've ever seen a "good" HDD crash !!
Yes, I should of had a back-up. I went out & bought one the next day
and have used it (and verify) EVERY DAY since. Sleep much better now.  :-)
Regards...
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Dave Duffy, Audio Visual Devices
8/9-11 Trade Street
Cleveland Qld 4163, Australia
Ph: +61 7 38210362 Fax: +61 7 38210281
E-mail: AVD@mailbox.uq.edu.au
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