A Push Button Algorithm Inquiry?

[ritchie]

Hello der!!!

Just a curiousity, What if I have a button-- when I press and hold it off course it will display a character corresponding to a keypress.

Is their an alogorithm when I press and hold the button it will only register one keypress for that specific button?

I need your comments, suggestions, sample snippets if any.

Thanx

[Neutone]

Do a search on debouncing.

[Jeprox]

You don't mean debouncing, do you, because it's simply a matter of putting a delay or a few scans before finally reading it, with each scan doing a comparison with the previous read.

A simple approach (there are many ways of doing it) is to put a flag, declared as a short int, that will check if the button is pressed, and sets a flag.

short int flag= 0;
int value;


//assuming your push button is tied to Vcc through a resistor.

if((input(PUSH_BUTTON) != 1) && count==0)
{
printf("%d\r\n", value );
flag = 1;
}

if(input(PUSH_BUTTON))
flag = 0;