pushbutton and loop algorithm

Discussion in 'Embedded Systems and Microcontrollers' started by Eric007, Aug 22, 2011.

1. Eric007 Thread Starter Senior Member

Aug 5, 2011
1,056
33
Good day Everybody!!!
Its a beautiful day, isn't?

What I'm actually trying to achieve is to control 2 loops by using a single pushbutton!

It should work as follows:
- 1st press, loop1 start running
- 2nd press, loop2 start running
- 3rd press, loop1 can re-start running
..........................
and so on...

Here's the algo I came up with:

Checkpress
if pressed goto loop1
if not pressed goto checkpress

Loop1
;loop1body
.......................
if pin=0 (which is a press) goto loop2
if pin=1 (which is not press) goto loop1

Loop2
;loop2body
........................
if pin=0 goto loop1
if pin=1 goto loop2

In the above algorithm, pin is the same pin in the checkpress loop...
Does it make sense? Please I need ur comment or if u have a more elegant way of achieving this please show me

Also, when power is put off and then put back on, where does the program start? Where it stopped or at the beginning of main? (Excuse me if this is a stupid question).

Eric007

2. ErnieM AAC Fanatic!

Apr 24, 2011
7,443
1,628
Well... that ain't gonna do much. If you press the button Checkpress will jump to Loop1, Loop1 will then jump to Loop2, and Loop2 will jump back to Loop1, which jumps to loop 2, which....

Nothing gets done. You need to also check in Loop2 that the button is NOT pressed before enabling the jump to Loop3.

Also, if this is a real push button you need to check if it is bouncing and not follow every bounce.

3. Eric007 Thread Starter Senior Member

Aug 5, 2011
1,056
33
@ErmieM: can u help me then come up with a better algorithm to achieve the above?
Actually I need to use this algo to turn a set of LEDs on and off using a "single" pushbutton!
And yes its gona be a real pushbutton!

4. Eric007 Thread Starter Senior Member

Aug 5, 2011
1,056
33
@Ermie: how about I change checkpress,for debouncing, as follow:

Checkpress
If pressed =>call delay
If not pressed got checkpress
If pressed goto loop1
If not pressed goto checkpress

Is that ok? And as for the delay, what's the time for it I mean how long should it take?

And regarding ur other comment for loop2, I do check if button is nit pressed before going back to loop1, isn't ???

Also there's no loop3...

Hope to get a comment from u!

Jun 2, 2010
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