Mark Birks asked about simulating the SLEEP instruction on a 16C64
using MPLAB.   He was trying to simulate the following:

>              LIST    P=16C64
>
>              MOVLW   0
>              TRIS    6
>              OPTION
> LOOP         SLEEP
>              INCF    6,1
>              GOTO    LOOP
>              END

This program should work fine on a 16C64 provided the watchdog is
enabled.  I only saw a couple of replies: M. Hagberg suggested that
the program wouldn't work because SLEEP resets the processor - though
that's what happens on 12-bit PICs it's not true for 14-bit PICs like
the 16C64; J. Scholz mentioned that you really should change to page 1
to set the TRIS and OPTION registers but that's not really necessary
as the TRIS and OPTION instructions do the same job even if they are
not recommended by Microchip.

To make things work:

1.  Ensure MPLAB-SIM is simulating watchdog timeouts by selecting
"Options|Processor Setup|Hardware" and checking the "WDT Break Enable"
radio button.  Now a watchdog timeout will happen every 18ms or so
(as dictated by the OPTION value of 0 used in the program).

2.  To see anything happen without having to wait forever choose a
clock frequency such that only a few cycles occur per 18ms watchdog
timeout period.  To do this select "Window|Stopwatch" and set "Target
Frequency" to 5 kHz (say).

3.  Either display all registers or add PORTB to a watch window with
"Window|New Watch Window".

4.  Simulate using "Debug|Run|Animate".

Hope that helps.

David
--
david.tait@man.ac.uk
http://www.man.ac.uk/~mbhstdj