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13.7
Port Event
13.8
Alternate Port Functions
8331B–AVR–03/12
Table 13-3.
Limited asynchronous sense support.
Sense Settings
Rising edge
Falling edge
Any edge
Low level
Port pins can generate an event when there is a change on the pin. The sense configurations
decide the conditions for each pin to generate events. Event generation requires the presence of
a peripheral clock, and asynchronous event generation is not possible. For edge sensing, the
changed pin value must be sampled once by the peripheral clock for an event to be generated.
For level sensing, a low-level pin value will not generate events, and a high-level pin value will
continuously generate events. For events to be generated on a low level, the pin configuration
must be set to inverted I/O.
Table 13-4.
Event sense support.
Sense Settings
Rising edge
Falling edge
Both edge
Low level
Most port pins have alternate pin functions in addition to being a general purpose I/O pin. When
an alternate function is enabled, it might override the normal port pin function or pin value. This
happens when other peripherals that require pins are enabled or configured to use pins. If and
how a peripheral will override and use pins is described in the section for that peripheral.
The port override signals and related logic (grey) are shown in
signals are not accessible from software, but are internal signals between the overriding periph-
eral and the port pin.
Supported
Interrupt Description
No
-
No
-
Yes
Pin value must be kept unchanged during wake up
Yes
Pin level must be kept unchanged during wake up
Signal event
Data event
Rising edge
Pin value
Falling edge
Pin value
Any edge
Pin value
Pin value
Pin value
Atmel AVR XMEGA AU
Figure 13-10 on page
151. These
150
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