On Sat, 10 Jan 1998 11:34:40 EST PHXSYS <PHXSYS@AOL.COM> writes:

>I am trying to control the position of a R/C servo using a Pot. I am
>timing
>the discharge of a capacitor to determine the pot position.
[...]
>  MEAS1   CLRWDT
>                      BTFSS  PORTB,0          ;Test b0 skip if 1
>                      GOTO   UP_DOWN
>                      INCFSZ PULSE1S,F  ;Inc pulse1s skip if 0
>                     GOTO   MEAS1            ;
>CLEANUP   MOVLW  0XFF
>                      MOVF   PULSE1S,W

As written, there is no way out of the measurement routine except when
PULSE1S overflows to 0.  You don't ever want to go back to UP_DOWN
(taking a new measurement) except as part of the main loop after doing a
servo pulse with the old measurement.  Rewrite it to something like:

meas_lp
        btfss   PORT_B,0                ;When cap has discharged,
        goto    meas_done               ;measurement done.
        incfsz  PULSE1S,f               ;Inc. measured value
        goto    meas_lp                 ;If no overflow, wait
more
        decf    PULSE1S,f               ;Fix overflow value back to
255
meas_done

The "cleanup", whatever it's supposed to do, appears unnecessary.  Make
sure the WDT prescaler is set high enough to guarantee that the WDT won't
run out during the 20 ms main loop.  Then clear it just at the start of
each main loop.  It would help to write the delay, cap measure, etc.
sections as subroutines.  This makes it easier to follow the flow through
the main loop as well as expand the function of the program later.