Reginald Neale <PICLIST@MITVMA.MIT.EDU> wrote:

> Does anyone have a favorite way to do a window comparison on an
> A/D result? .... What I want to do is to insert code in an existing
> loop that will set an alarm output pin if the A/D result falls
> outside the window; set another pin high if it is below the
> hard-coded lower limit, set a different pin if it is above the
> upper limit, and continue on without setting any of the three if
> the result is within the window.

Reg:

Try this; I haven't even assembled it, let alone tested it, but it
SHOULD work...

    MOVF    ADRES,W

    ADDLW   256-UPPER       ;These 4 lines were written by
    ADDLW   (UPPER-LOWER)+1 ;a smart guy named Eric Smith.
    SKPNC                   ;
    GOTO    DONE            ;

    ;Our A/D result was outside the [LOWER-UPPER] window.

    BSF     ALARMPIN        ;Set the ALARM pin.

    ADDLW   LOWER-1         ;Was ADRES too low?
    SKPC                    ;If so, skip ahead.
    BSF     HIGHPIN         ;Otherwise, set the HIGHPIN pin.
    SKPNC                   ;If ADRES was too high, skip ahead.
    BSF     LOWPIN          ;Otherwise, set the LOWPIN pin.

  DONE:

-Andy


=== Andrew Warren - fastfwd@ix.netcom.com
=== Fast Forward Engineering - San Diego, California
=== http://www.geocities.com/SiliconValley/2499