Port A pins

I am just getting into microcontroller programing and am haveing trouble geting the port A pins to go high and low. I dont really understand how to get thoes pins to go high and low. My micorcontroller is a pic16f84. If someone could give me the assembly code to make a specific A pin go high, and descrive exactly what is going on in the code I would appreciate it.

Thanks

Few start point
http://www.picbasic.co.uk/forum/show...hlight=dummies

Code:

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;        Super dooper LED blink with 10F200
;        ==================================
;        Steve Monfette
;        Mister E
;        23/03/2006

;        As if the world really needed it... well it's still usefull
;        to learn a bit how to play and waste your time using the
;        annoying assembler language.  BTW 10F200 are just too small
;        to accept any other language.

;        This program will use a software loop delay, called by a macro
;        wich will pass the delay to produce... at least not too basic and
;        some part could be usefull.. one day if someones really try to figure
;        out how it works... just kidding.. i know EVERYBODY WILL TRY ;o)
;        ---------------------------------------------------------------------

        INCLUDE "P10F200.INC"        ; load all needed stuff

;        PIC configuration
;        =================
        __Config _MCLRE_ON & _CP_OFF & _WDT_OFF
       
;        Hardware assignement
;        ====================
        #define Led                        GPIO,2       
       
;        RAM assignement
;        ===============
;        hands-up those who discover figure 4-3

        cblock 0x10                               
                loop               
                UserDelay
        endc

;        Macro Definition
;        ================
;        Be carefull, the following macro is extremely difficult to understand
;        and contain tons of information... always refer to MPASM book to
;        understand all trick it do.. mpff mkay i stop it :o)

;        Nothing fancy, the macro will just pass the parameter to the 1 msec
;        subroutine -> Delay <- Not much.  What could she do more to be still
;        code efficient anyway?

Delayms        macro User                               
        movlw        User                ; put User wish somewhere
        movwf        UserDelay        ; copy it to something
        call        Delay                ; do the delay       
        endm                               
   
;        ///////////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
;                                        Program Begining       
;        ///////////////////////////////////////|\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\

;        Hardware configuration
;        ======================
        ORG 0                        ;
        movwf        OSCCAL                ; Load OSCCAL value

        movlw        b'11111011'        ;
        TRIS        GPIO                ; Set GP2 as Output

        movlw        b'11011111'        ; TOCS=internal => to use GP2 as Output
        OPTION                        ; => datasheet section 4.5       

;        Tha ****!
;        =========
;        The exciting part of the program... how to blink a LED
Start
        bsf        Led                ; Enable LED
        Delayms d'250'                ; do 250 mSec Delay       
        bcf                Led        ; Disable LED
        Delayms        d'250'                ; do 250 mSec Delay
        goto        Start                ; Have fun forever, enjoy the show

;        Delay Subroutine
;        ================
;        The main program call the macro, the macro call this routine
Delay       
            movlw  d'250'                ; 1 mSec base
            movwf  loop                  ;        loop

          ;        DelayLoop
          ;        ---------
            nop                          ; do nothing                (1 Cycle)
            decfsz  loop,f                    ; base loop finished?      (1 cycle if NO, 2 cycle if YES)
            goto    $-2                  ; NO... jump 2 lines before (2 cycles)
                                    ;                            -------------------------------
                                    ;              Killed about 4 cycles * 250times @1uSec = 1mSec
                                    ;
            decfsz        UserDelay,f        ; DelayFinish?
            goto        $-6                ; NO... do it again, jump 6 line before
            retlw        0                ; Astalavista baby
            end

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Perhaps you have figured it out by now.

Anyway, use "poke" + the "A" register + a binary discription of how you want the 4 pins.

If you want them all high:

POKE $5,%1111

All low:

POKE $5,%0000

i guess you misread the following part ;)

Quote:

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Originally Posted by Eric123

If someone could give me the assembly code to make a specific A pin go high, and descrive exactly what is going on in the code I would appreciate it.

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