Hi Guys,

I 'm using microchip's simulator (MPSIM 5.20) to test my program. For the
loading and the execution of the program, everything went alright. However,
I'm experiencing difficulty  creating the stimulus file.

I'm not too clear on how the steps in the this file are determined. For the
example (see below) given in the users manual, there is  cycle 3, cycle 10,
cycle 16  etc. in the Column Headings section, corresponding with step 3,
step 4, step 9 etc. Where did these numbers come from?

Thanks for your speedy response.

Rawle


STEP    RB2     RA3   RA2   RA1   RA0     !Column Headings
3        0      0     1      0     0       !stimulus before cyc1e 3
4        1      0     1      0     1       !injected before cycle 10
9        1      1     0      1     0       !injected before cycle 16
10       0      1     0      1     1       !stimulus before cyc1e 3
15       0      0     0      0     0       !injected before cycle 9
16       1      0     0      0     1       !injected before cycle 15

Fig 1.  Stimulus file (sample.sti)




;*******************************************************************
;                           SAMPLE.ASM
;                   8x8 Software Multiplier
;*******************************************************************
;
;   The 16 bit result is stored in 2 bytes
;
; Before calling the subroutine " mpy ", the multiplier should
; be loaded in location " mulplr ", and the multiplicand in
; " mulcnd " . The 16 bit result is stored in locations
; H_byte & L_byte.
;
;       Performance :
;                       Program Memory  :  15 locations
;                       # of cycles     :  71
;                       Scratch RAM     :   0 locations
;
;  This routine is optimized for code efficiency ( looped code )
;  For time efficiency code refer to "mult8x8F.asm" ( straight line code )
;*******************************************************************
;
        LIST    p=16C54 ; PIC16C54 is the target processor

mulcnd  equ     09      ; 8 bit multiplicand
mulplr  equ     10      ; 8 bit multiplier
H_byte  equ     12      ; High byte of the 16 bit result
L_byte  equ     13      ; Low byte of the 16 bit result
count   equ     14      ; loop counter
portb   equ     06      ; I/O register F6
STATUS  equ     03      ; STATUS register F3
CARRY   equ     0       ; Carry bit in status register
Same    equ     1       ;
;
;
; *****************************         Begin Multiplier Routine
mpy_S   clrf    H_byte
        clrf    L_byte
        movlw   8
        movwf   count
        movf    mulcnd,w
        bcf     STATUS,CARRY    ; Clear the carry bit in the status Reg.
loop    rrf     mulplr,Same
        btfsc   STATUS,CARRY
        addwf   H_byte,Same
        rrf     H_byte,Same
        rrf     L_byte,Same
        decfsz  count,Same
        goto    loop
;
        retlw   0
;
;********************************************************************
;               Test Program
;*********************************************************************
start   clrw
        option
main    movf    portb,w
        movwf   mulplr          ; multiplier (in mulplr) = 05
        movf    portb,w
        movwf   mulcnd
;
call_m  call    mpy_S           ; The result is in locations F12 & F13
                               ; H_byte & L_byte
;
        goto    main
;
        org     01FFh
        goto    start
;
     END





































Bye,
Rawle.