29.6.3.4. Digital Functionality Disabled
Neither Input nor Output functionality are enabled.
Figure 29-9. I/O Configuration - Reset or Analog I/O: Digital Output, Input and Pull Disabled
PULLEN
DIR
OUT
IN
INEN
PULLEN INEN
DIR
0
0
0
29.6.4. Events
The PORT allows input events to control individual I/O pins. These input events are generated by the
EVSYS module and can originate from a different clock domain than the PORT module.
The PORT can perform the following actions:
•
Output (OUT): I/O pin will be set when the incoming event has a high level ('1') and cleared when
the incoming event has a low-level ('0').
•
Set (SET): I/O pin will be set when an incoming event is detected.
•
Clear (CLR): I/O pin will be cleared when an incoming event is detected.
•
Toggle (TGL): I/O pin will toggle when an incoming event is detected.
The event is output to pin without any internal latency. For SET, CLEAR and TOGGLE event actions, the
action will be executed up to three clock cycles after a rising edge.
The event actions can be configured with the Event Action m bit group in the Event Input Control
register( EVCTRL.EVACTm). Writing a '1' to a PORT Event Enable Input m of the Event Control register
(EVCTRL.PORTEIm) enables the corresponding action on input event. Writing '0' to this bit disables the
corresponding action on input event. Note that several actions can be enabled for incoming events. If
several events are connected to the peripheral, any enabled action will be taken for any of the incoming
events. Refer to
EVSYS – Event System
. for details on configuring the Event System.
Each event input can address one and only one I/O pin at a time. The selection of the pin is indicated by
the PORT Event Pin Identifier of the Event Input Control register (EVCTR.PIDn). On the other hand, one
I/O pin can be addressed by up to four different input events. To avoid action conflict on the output value
of the register (OUT) of this particular I/O pin, only one action is performed according to the table below.
Note that this truth table can be applied to any SET/CLR/TGL configuration from two to four active input
events.
Table 29-3. Priority on Simultaneous SET/CLR/TGL Event Actions
EVACT0
EVACT1
EVACT2
EVACT3
Executed Event Action
SET
SET
SET
SET
SET
CLR
CLR
CLR
CLR
CLR
All Other Combinations
TGL
Be careful when the event is output to pin. Due to the fact the events are received asynchronously, the
I/O pin may have unpredictable levels, depending on the timing of when the events are received. When
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