Memory Space of the PIC16F84...

[mister_e]

Hi Michael,
Try the following and post results. Where i am now i can't test it

' I am working on a delay project which uses 2 buttons one for increasing the 
' delay and one for decreasing the delay. I am using the PIC16F84 and have a 
'
' buttons:
' ========
'         connected to PORTB pin 5,6. 
'                   pin 5 : increase
'                   pin 6 : decrease
' LEDS:
' =====
'      PORTB pin 4 : showing the length of the delay, 
'            pin 3 : showing when both buttons are pushed that it saves 
'                    the delay to EEPROM, 
'            pin 7 : showing when IncreaseButton is pushed
'
'      PORTA pin 3 for when DecreaseButton is pushed.

    TRISB=%01100000  ' PORTB<6:5> as input 
                     ' others as output
                     '
    TRISA=0          ' set all PORTA as output
    
    LEDLength   var PORTB.4
    LEDSave     var PORTB.3
    LEDIncrease var PORTB.7
    LEDDecrease var PORTA.3
    
    Delay       var word
    Loop        var word
    PB          var byte
    Increase    con 1
    Decrease    con 2
    Both        con 3
    
    data @0,5,$DC         ' store initial 1.5 sec
    
    PORTB=0 '
            ' Clear all LEDs
    PORTA=0 '

DelayLoop:
    read 0,delay.highbyte ' Read delay
    read 1,delay.lowbyte  ' from EEPROM
    
    ledlength=1           ' Enable Length LED
    
    for loop=0 to delay   ' Do the delay and do PushButton tests
        pause 1
        pb=(PORTB>>5)& 3  ' keep only PORTB.5 and PORTB.6 bits
        
        if pb then        ' If there's at least one push button press
           select case Pb ' choose according thing to do
                  case increase
                       if delay<=60000 then
                          delay=delay+500
                          ledincrease=1
                          endif
                     
                  case decrease
                       if delay>=500 then 
                          delay=delay-500
                          leddecrease=1
                          endif
                     
                  case both
                       ledsave=1
                       write 0, delay.highbyte
                       write 1, delay.lowbyte
                  
                  end select
           pause 100     ' kinda auto repeat delay... can be higher/lower 

           ledincrease=0 ' Clear all pushButtons
           leddecrease=0 '       related
           ledsave    =0 '         LEDs
           endif
        next
    ledlength=0     ' confirm delay is finished
    pause 500       ' wait a little bit
    goto DelayLoop  ' redo the delay and blah blah

[Tear]

Thank you SOOOOOOO much Steve!!!!!! This code is exactly what I need to make it work! My poor, unefficent code was doing the job, but this is so much cleaner and easier to use!

I defiantly have a lot of learning to do. This was my first attempt at writing my own program.

Also, with your version of this code I save nearly half the words!

I have been studying the way you have wrote this code and I dont understand how this line works. I understand what it does but not how. I am just curious on this one?

pb=(PORTB>>5)& 3 ' keep only PORTB.5 and PORTB.6 bits

Thanks,
Michael

[mister_e]

Great, but there's a tons of way to it more efficient. i was just trying to do something readable. Glad to know it's work as you wish. Hard to test when you're out of the city in a hotel room with a simple laptop.

BTW let's look at
pb=(PORTB>>5)& 3 ' keep only PORTB.5 and PORTB.6 bits


this line read the whole PORTB and shift bits 5 position to the right and finnaly do a bitwise AND with 3.
WHY... easier to read...and get only push buttons state

let's see how it's work.

Let's assume that PORTB=%11100000
after >>5 = we have %00000111
after & 3 we have %00000011 = 3 => both push buttons

Of course we an also use PB=PORTB & %01100000
and modify the Increase, decrease and Both constant definition too. That will save some code space and will do the same job. Or skip the Constant definition and place the expected value in the Select Case, or, or or , or...Posibility are endless.

Sometimes, there's a choice to do. Having a readable code or a less readable but really tight. It's case by case.

My last project use a 18F4620 and the full 64K of code. I spent many hours to shrink it as i can each time i add a new feature BUT I was out of codespace to implement new feature(on customer request)and i spend several hours to shrink everything by using PBP macro and do some workaround. Less readable but work as well as it suppose to.

Great to know it's working fine for you.

Have fun!