Post by thread:Lookup tables

Hello all! Can anyone point me in the right direction for info on lookup tables, Including how to implement and use. For example I want to use 30 or 40 different time delays, I assume using a lookup table would save me writing 30 or 40 routines? As you can guess, still new to the world of PICS but learning ! Thanks in advance Kev

So this is too easy for anyone to bother answering? Kev Howard wrote: > Can anyone point me in the right direction for info on lookup tables, > Including how to implement and use. > > For example I want to use 30 or 40 different time delays, I assume using a > lookup table would save me writing 30 or 40 routines? > > As you can guess, still new to the world of PICS but learning ! You basically call a subroutine which uses the 'retlw' instruction to put your values into W. table: addwf PCL retlw value1 ;index 0 retlw value2 ;index 1 ... Gotchas: Make sure that W can't have a value outside table bounds. (use 'andlw BITMASK' if your table is a binary length (32), or a compare & carry test if not). Table must be entirely contained within a page (xx00-xxFF) unless you go through some code gyrations to split it. Go to microchips web site http://www.microchip.com and READ THE APP NOTES. There are hundreds of good code examples to be found there.