I wrote the listing below and it assembled fine and it runs on the microchip
simulator.
I have programmed the 16c84 with the serial programmer and the code reads back
 fine
which confirms that it has been programmed but when I put the PIC in circuit
 nothing
happens.
I am holding the MCLR line high and am using a 4MHz crystal with 15p capacitors
 to
ground and LEDs on port b outputs.

Is this circuit correct and does the code check out ok? (reset vector etc.?)


Any help would be appreciated. (If I can't get this working, there's not much
 hope
for anything more advanced!)

count1  equ     0C
count2  equ     0D
portb   equ     06

        org     0

init
        movlw   0
        tris    portb                   ; set as outputs
        movwf   portb                   ; set portb levels all low

start
        bsf     portb,0                 ; set working reg bit 0 high


rot_L   call    wait
        rlf     portb,same
        btfss   portb,7
        goto    rot_L

rot_R   call    wait
        rrf     portb,same
        btfss   portb,0
        goto    rot_R
        goto    rot_L

; ----------------------------
; wait subroutine
; ----------------------------
wait
        movlw   .4              ; load count1 with decimal 4
        movwf   count1
d1      movlw   .100            ; load count2 with decimal 100
        movwf   count2
d2      decfsz  count2,same     ; decrement and skip next line if zero
        goto    d2              ; if not zero
        decfsz  count1          ; decrement count1 if count2 is zero
        goto    d1              ; do inside loop again if count2 nz
        retlw   00
; ----------------------------

END




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