debounce Archives - Stefan On Software

Simple AVR Button Debounce

14 Jan

I needed a simple debounce for a push button wired directly to a digital input on an ATMega. I’m sure there are more advanced techniques but this is working well for me.

int ButtonPressed()
{
 /* the button is pressed when BUTTON_BIT is clear */
 if (bit_is_clear(BUTTON_PIN, BUTTON_BIT))
 {
  delay_ms(DEBOUNCE_TIME);
  if (bit_is_clear(BUTTON_PIN, BUTTON_BIT)) return 1;
 }
 return 0;
}

int ButtonPressed()

{

/* the button is pressed when BUTTON_BIT is clear */

if (bit_is_clear(BUTTON_PIN, BUTTON_BIT))

{

delay_ms(DEBOUNCE_TIME);

if (bit_is_clear(BUTTON_PIN, BUTTON_BIT)) return 1;

}

return 0;

}

Where bit_is_clear is defined in AVR-LIBC IO.H … Read More »