>
> Breadboarded first circuit with Picmicro, wrote a test program
> in Mplab / Mpasm. Runs/assembles sucessful in Mplab sim
> w/watch windows etc.
> Programed chip using a Micro Engineering Labs EPIC programer.
> Circuit has 8 leds on portb, when powered up all leds light up
> (portb high, not what it is supposed to do). Thought it was a
> problem with my circuit or one of the parts etc. After changing
> parts, testing etc., for the fun of it I took a demo program that came
> with the programer made some changes assembled it using melabs Pic Macro
> Assembler program and programed the chip and the circuit worked just like
> it is suppose to? Tried many changes to program in Mplab/Mpasm and
> reprograming the chip with the same results (runs well in sim, but does
> not run in circuit) and program demo from melabs works. I must be missing
> something. I really want to use Mplab/Mpasm for developing. I have
> included the code below, any help would appreciated. I'm using;
> PIC16F84A-20, Mplab v4.12.12, EPIC programer from Micro Egineering Lab.
> ***************************************************************
> #1)below program from Mplabs - (crude, should work but does not)
> email may have played with tabs and line length
> ***************************************************************
>  list      p=16F84A
>  include <p16f84a.inc>
>
>  __CONFIG   _CP_OFF & _WDT_OFF & _PWRTE_ON & _HS_OSC
>
> portb   equ     0x06
> count   equ     0x0c
> ;---------------------------
>             org       0x000
> ;
> start   movlw   0x00    ;load W with 0x00
>            tris       portb     ;copy W tristate, port B outputs
>
>            clrf       portb     ;all lines low
> ;
>
>            bsf        portb,0   ;turn on led
>
> go            bsf             portb,0   ;turn on led
>            call       delay     ;delay via sub
>            bcf        portb,0   ;turn off led
> ;
>            bsf        portb,1   ;turn on led
>            call       delay     ;delay via sub
>            bcf        portb,1   ;turn off led
> ;
>            bsf        portb,2   ;turn on led
>            call         delay   ;delay via sub
>            bcf        portb,2   ;turn off led
> ;
>            bsf        portb,3   ;turn on led
>            call         delay   ;delay via sub
>            bcf        portb,3   ;turn off led
> ;
>            bsf        portb,4   ;turn on led
>            call       delay     ;delay via sub
>            bcf        portb,4   ;turn off led
> ;
>            bsf        portb,5   ;turn on led
>            call         delay   ;delay via sub
>            bcf        portb,5   ;turn off led
> ;
>            bsf        portb,6   ;turn on led
>            call       delay     ;delay via sub
>            bcf        portb,6   ;turn off led
> ;
>            bsf        portb,7   ;turn on led
>            call       delay     ;delay via sub
>            bcf        portb,7   ;turn off led
> ;
>            goto go            ;repeat
> ;
> delay   movlw   0x02    ;decimal 10
>             movwf       count   ;load counter
> repeat  decfsz  count,f ;decrement counter
>            goto repeat  ;not 0
>            return                     ;counter 0, end delay
> ;
>  end
> ************************************************************
> #2) below from melabs demo (assembled w/ Pic Macro Assembler)
> This code works.
> email may have played with tabs and line length
> *************************************************************
>         maclib  'p16f8x.inc'
> ;
>         device  pic16f84,hs_osc,wdt_off,pwrt_on,protect_off
> ;
> leds    =       portb           ;led output port
> ;
> dir_b   =       00h             ;all out
> ;
>           org     0ch             ;start of ram space
> ;
> binary  ds      1               ;binary count
> cnt_low ds      1               ;delay counters
> cnt_mid ds      1
> cnt_high ds     1
> ;
>        org     0               ;reset vector
> ;
>         jmp     start           ;go to beginning of program on reset
> ;
>        org     5               ;start of code space
> ;
>            retw    'DEMO84 Rev 1.3'
> ;
> ;
> ; delay for about 1 second based on 4mhz clock cycle
> ;
> delay    mov     cnt_high,#4
>        clr     cnt_mid
>        clr     cnt_low
> delay1  nop
>        djnz    cnt_low,delay1
>        djnz    cnt_mid,delay1
>         djnz    cnt_high,delay1
>         ret
> ;
> ;
> ; it all starts here
> ;
> start     mov     leds,#0         ;start with all leds off
>            setb    rp0             ;point to register page 1
>            mov     trisb,#dir_b    ;set port b data direction register
>            clrb    rp0             ;point back to register page 0
> ;
> ;
> ; main loop to send binary sequence to port b
> ;
>         mov     binary,#1       ;start with first led on
> ;
> mainloop mov    leds,binary     ;send the binary count to the leds
> ;
>               call    delay           ;wait around a second
> ;
>               inc     binary          ;increment to next binary value ;
>               jmp     mainloop        ;do it forever
> ;