On 11 Sep 96 at 20:22, M Walter wrote:

> 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?

Is it reachable by normal execution?

PS the TRIS instruction seems to be being phased out in preference of
the TRIS registers.

>
> Anyone have any hints for disassembling code from the hex file?

Yes.  Ppls first impression will probably be that you're doing some
illicit hacking <g>

Strings/ lookup tables look funny.  Lots of retlw statements,
usually.
MikeS
<mikesmith_oz@nosp*m.relaymail.net>
(remove the you know what before replying)