GPIO

• Each Port Has

  • Data Direction (DIR)
    • 1 for OUT, 0 for IN
  • Data Output (OUT)
  • Data Input (IN)

• The following Port registers are available

  • DIR – Data Direction register
    • If a one is written to DIRn, pin n is configured as an output pin – If a zero is written to DIRn, pin n is configured as an input pin
  • DIRSET – Data Direction Set Register
    • Writing a one to a bit will set the corresponding bit in DIR – Reading will return the value of the DIR register
  • DIRCLR – Data Direction Clear Register
    • Writing a one to a bit will clear the corresponding bit in DIR – Reading will return the value of the DIR register
  • DIRTGL – Data Direction Toggle register
    • Writing a one to a bit will toggle the corresponding bit in DIR – Reading will return the value of the DIR register
  • OUT – Data Output Value
    • Sets the data output value for the individual pins of the port – If a one is written to OUTn, pin n is driven high
    • If a zero is written to OUTn, pin n is driven low
    • For this to have any effect, the pin direction must be output
  • OUTSET – Data Output Value Set register
    • If a one is written to bit n, OUTn is set; writing a 0 has no affect – Reading this register will return the value in the OUT register
  • OUTCLR – Data Output Value Clear register
    • If a one is written to bit n, OUTn is cleared Writing a zero has no affect
    • Reading this register will return the value in the OUT register
  • OUTTGL – Data Output Value Toggle register
    • If a one is written to bit n, OUTn will toggle; writing a zero has no affect
    • Reading this register will return the value in the OUT register
  • IN – Data Input Value register
    • INn shows the value of pin n
    • The input is not sampled and cannot be read if the digital input buffers are disabled