push button

[freedom]

Hi there.
I am new in PIC programming.
I want to make a lcd counter with a push button in following condition...

1. I want to count in each push.
2. If I push and hold it nothing count until I release the push button.

Need your help

my code as follows

[SherpaDoug]

I would use a "state machine" with two states, 'in' and 'out'.

When in state 'out' wait for the button to be pushed in for 100ms, then increment the count and go to state 'in'. If the button is let out before 100ms remain in state 'out'.

When in state 'in' wait for the button to be let out for 100ms, then go to state 'out'. If the button is pushed in before 100ms remain in state 'in'.

The 100ms delay is a simple debouncing technique for mechanical switches. There are more sophisticated methods, but you need to know more about just how your switch behaves before you get too complex.

The state machine technique is very powerful and if you use more states with clearly defined rules to go from one state to another you can do very complex things with great reliability.
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The search for better is endless. Instead simply find very good and get the job done.

[freedom]

Thanks SherpaDoug for your kind reply.

Actually I'm going to develop a machine where I need to use it. Actually a inductive proximity sensor will be used there which is acted as similar as push button.

In my operation, there are some situation where the push switch in hold for 10 sec or 30 sec or 2 min or 30 min or etc.

In my above mentioned code , when i press its counting. But problem is that I want count only one time in each press, If I hold it then do nothing until I release the switch and push it again.

Waiting for your help.

[Jhonny]

Here is my version. There is a parameter that monitors the key is released and pressed (status). I hope you understand ...

[PCM programmer]

Here is the "Button Command" code that I wrote for the Code Library:
http://www.ccsinfo.com/forum/viewtopic.php?t=23837

Here's a version of it that polls the buttons during a timer interrupt:
http://www.ccsinfo.com/forum/viewtopic.php?t=31849

This version stores the button presses in a buffer, which can be read:
http://www.ccsinfo.com/forum/viewtopic.php?t=39585&start=1

This code can detect if the button is pressed, held, released or up:
http://www.ccsinfo.com/forum/viewtopic.php?t=42027

[SherpaDoug]

With my state machine suggestion it will only count a single count when it goes from state 'out' to state 'in'. You can hold the button in all day and you will only get one count because you only ENTER state 'in' once. It can't make a second count until it exits 'in' and enters 'out' and exits 'out' and enters 'in' again. One count per button press.
_________________
The search for better is endless. Instead simply find very good and get the job done.

[freedom]

Thanks a lot Jhonny, PCM programmer and SherpaDoug for your valued reply.

I'm going to try Jhonny's code. I'll be back very soon what happened.

Telling to SherpaDoug , would you like to show code example as I am new in PIC programming.

[freedom]

Thanks a lot Jhonny

it is working

[SherpaDoug]

Jhonny's code would be a true state machine with the addition in bold:

if (input (PIN_A4) && status==1)

But as you can see, in this trivial case it is not needed.
_________________
The search for better is endless. Instead simply find very good and get the job done.