• 255 if the pin was in the active state for given period.
• 0 otherwise

Function eliminates the influence of contact flickering upon pressing a button (debouncing).

Parameter port specifies the PIN register of the desired port; parameter pin is the pin number on designated port and goes from 0..7; parameter time is a debounce period in milliseconds; parameter active_state can be either 0 or 1, and it determines if the button is active upon logical zero or logical one.

Button pin must be configured as input.

On every PB0 one-to-zero transition PORTC is inverted :

program Button_Test

dim oldstate as bit

main:
  DDB0_bit = 0                                        ' set Button pin as input

  DDRC  = 0xFF                                        ' configure PORTC as output
  PORTC = 0xAA                                        ' initial PORTC value

  oldstate = 0                                        ' oldstate initial value

  while TRUE
      if (Button(PINB, 0, 1, 1) <> 0) then            ' detect logical one
        oldstate = 1                                  ' update flag
      end if
      if (oldstate and Button(PINB, 0, 1, 0)) then    ' detect one-to-zero transition
        PORTC = not PORTC                             ' invert PORTC
        oldstate = 0                                  ' update flag
      end if
  wend                                                ' endless loop
end.