button question

Nick

a while back i saw a post that explained how to have a single button do multiple things ie. the first time you press it it did x. the second it did y, and the third it did z. anyone seen this post, or know how to do it?

I have a keypad that is interfaced to the stamp via serial. and i would like to be able to 'scroll' through commands with one button on the keypad.

Thanks

KenM

I am going to make a suggestion on how to do what you want. However, I am quite sure there is a more elegant way to accomplish your task.
Assuming you need no more than 16 tasks based on the next button press....

1. You will need to de-bounce the button contact. There is plenty of documentation on how to do that
2. Set up a nibble variable to act as a counter

Before the button is pressed the first time,·initialize your counter
Each time the button is pressed, increment the counter by one
Depending on the counter value, call the subroutine that you want to occur.
After the last event occurs,·re-initialize your counter
EX;
You want to do 4 subroutines, call them sub1, sub2, sub3, sub4 (but you will use more usefull names).

The example below is by no means complete, but I hope you see the big picture to help you get started.

buttonmem var nib
 
buttonmem = 1
 
 
 
again:
 
 
   SELECT buttonmem
    CASE 1                         'check for 1st button press
     buttonmem = buttonmem + 1     'increment the value of buttonmem by one
     GOSUB sub1                    'call "first" subroutine in sequence
 
    CASE 2                          'check for 2nd button press
     buttonmem = buttonmem + 1      'increment the value of buttonmem by one
     GOSUB sub2                     'call "second" subroutine
 
    CASE 3                          'check for 3rd button press
     buttonmem = buttonmem + 1      'increment the value of buttonmem by one
     GOSUB sub3                     'call "third" subroutine
 
    CASE 3                          'check for last button press
     buttonmem = 1                  'increment the value of buttonmem by one
     GOSUB sub4                     'call "last" subroutine in sequence
 
   ENDSELECT
 
GOTO again

Post Edited (KenM) : 5/1/2005 2:59:49 PM GMT