18.3.1 Initialization
After Reset, all outputs are tri-stated, and digital input buffers enabled even if there is no clock running.
The following steps are all optional when initializing PORT operation:
- Enable or disable the output driver for
pin Pxn by respectively writing ‘
1’ to bit n in the PORTx.DIRSET or PORTx.DIRCLR register - Set the output driver for pin Pxn to
high or low level respectively by writing ‘
1’ to bit n in the PORTx.OUTSET or PORTx.OUTCLR register - Read the input of pin Pxn by reading bit n in the PORTx.IN register
- Configure the individual pin configurations and interrupt control for pin Pxn in PORTx.PINnCTRL
Important: For the lowest possible
power consumption, disable the digital input buffer of unused pins and pins are used as
analog inputs or outputs. For pins with the digital input buffer enabled it is recommended
to transition between the high and low voltage thresholds as quickly as possible.
Specific pins, such as those used to connect a debugger, may be configured differently, as required by their special function.