Steve Smith wrote:

> That's because the addition to PCL is 8 bit and the high bits aren't
> managed properly(16xx doesn't have 16 bit add command) you need to
> increment PCLATH for the next section of the table (I only found this
> out last weekend) There is a good worked example in the techref at
> piclist.com. The basic understanding I got from the list (thanks David
> and Jan-erik Olin and others) is that the addwf pcl is limited to 8 bits
> but a direct goto is 11 bits and PCLATH 3,4 are the page bits. This
> leaves bits 0-3 of PCLATH which need to be set according to the page
> location on computed (addwf PCL,F)jump. Hence a table that starts at
> 0800h is called after setting PCLATH,3 to 1 and the continuation of the
> table past 0900H requires a conditional incf PCLATH,f to continue the
> table past the first 256b
<snip>

The easiest way to handle this is to make sure PCLATH is set right
before you perform the computed jump, THEN make sure that all possible
jumop-to locations are in the same page...The code is then trivial.

--Bob

--
              --------------
                Bob Axtell
        PIC Hardware & Firmware Dev
          http://beam.to/baxtell
              1-520-219-2363

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu