$regfile = "2313def.dat"
$crystal = 4000000

Config Sda = Portd.5
Config Scl = Portd.4
Config I2cdelay = 10

Config Pind.6 = Output
Config Pind.2 = Input
Config Int0 = Falling

Const Pcf8574write = &H40
Const Pcf8574read = &H41

Const Shortwait = 50
Const Longwait = 250

Const Switchbit = 0

Dim Ledwait As Byte
Dim Pcf8574port As Byte

Ledwait = Shortwait

On Int0 Pcfint

Enable Interrupts
Enable Int0

'Make all Pcf8574 pins high -> input
I2cstart
I2cwbyte Pcf8574write
I2cwbyte 255
I2cstop

Do
  Set Portd.6
  Waitms Ledwait
  Reset Portd.6
  Waitms Ledwait
Loop

'PCF8574 interrupt routine
Pcfint:
  'debounce wait time
  Waitms 10
  'read the input pins
  I2cstart
  I2cwbyte Pcf8574read
  I2crbyte Pcf8574port , Nack
  I2cstop
   'Determine state of Switchbit bit
  If Pcf8574port.switchbit = 1 Then
    Ledwait = Shortwait
  Else
    Ledwait = Longwait
  End If
  Gifr = 64
Return
End