On Tue, 7 Mar 2000, Steve Horvath wrote:

> Hello
> I am fairly new to PIC programming, but have a fair bit of experience form
> school involving the Intel 8031.  I was wondering if someone could write a
> quick program (2 minute job) to do the fallowing on a 16f84, so that I
> could learn about these functions by doing them:

Hi Steve;

Two minutes eh? Well, I give it a shot.

On my mark, get set.....GO!


> -push W onto a stack, and pop W off of the stack
 #include"include/stack.asm"

 call push
 call pop

> - input from port A to W when there is an interrupt
        org     0x04
        goto    InterruptHandler

InterruptHandler
        movf    PORTA,w
        retfie

> - have a 10ms delay using the timer

        bsf     STATUS,RP0      ;go into page one
        movlw   OPTIONInitial   ;set the prescalar and things
        movwf   OPTION_REG

        bcf     STATUS,RP0      ;back down to page zero
        movlw   TMR0TenMsDelayNumber
        movwf   TMR0
LoopDeeDoo
        movwf   TMR0
        addwf   0x00
        btfss   STATUS,Z
        goto    LoopDeeDoo

> - output to pb.0 through pb.4 after the interrupt
InteruptHandler
        andlw   0x0f    ;mask off the unwanted bits
        andwf   PORTB,w ;write to the port


> - have a 1 second timer using loops, and have the output (port B) blink on
> and off every second thereafter.
>
        #define BIT     ;any bit you want
LoopDeeDoo
        call    OneSecondTimerLoop
        btfsc   PORTB,BIT       ;Set yet?
        goto    $+3             ;Yes-> reset it
        bsf     PORTB,BIT       ;No-> set it
        goto    $+2             ;skip out
        bcf     PORTB,BIT
        goto    LoopDeeDoo

>
> oh, and could someone tell em the difference between portA and trisA?
TRISA sets the direction. Remember 1 = Input

>
> thanks for your help, this should pretty well be what I need to get
> everything straightened out.

Stop!
That took three minutes. Do I get payed overtime? No doubt all sorts
of piclisters will be correcting it anyway...

   Steve, I have been playing with PICS when time permits for the last
couple of years. Although my programming methods may be less then
professional, I have found the little buggers most intriguing.

   I use a dt001 programmer and various simmsticks with pics on them.
See http://www.dontronics.com.
and http://www.wirz.com

Although I really have nothing to compare with, it seems to be a good
low-cost system.

Freee programming and simulation software comes from Microchip
See http://www.microchip.com



>
> Steve Horvath
>


Jeffrey D. Spears
University of Michigan
College of Engineering

``Double-E, can't spell gEEk without it!''
                        -Captain Gerald M. Bloomfield II, USMC
                         (my brother)