Microchip Technology megaAVR 0 Series Manual page 141

Asynchronous Sensing Pin Properties
PORT supports synchronous and asynchronous input sensing with interrupts for selectable pin change
conditions. Asynchronous pin change sensing means that a pin change can wake the device from all
sleep modes, including modes where no clocks are running.
Table 15-3. Behavior Comparison of Fully/Partly Asynchronous Sense Pin
Property
Minimum pulse
width to trigger
interrupt
Waking the device
from sleep
Interrupt "dead time" No new interrupt for three cycles after the
Minimum Wake-up
pulse length
15.3.4 Events
All PORT pins are asynchronous event system generators. PORT has as many event generators as there
are PORT pins in the device. Each event system output from PORT is the value present on the
corresponding pin if the digital input driver is enabled. If a pin input driver is disabled, the corresponding
event system output is zero.
PORT has no event inputs.
15.3.5 Sleep Mode Operation
With the exception of interrupts and input synchronization, all pin configurations are independent of sleep
mode. Peripherals connected to the Ports can be affected by sleep modes, described in the respective
peripherals' documentation.
The PORT peripheral will always use the Main Clock. Input synchronization will halt when this clock
stops.
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2018 Microchip Technology Inc.
Synchronous or Partly Asynchronous
Sense Support
Minimum one system clock cycle
From all interrupt sense configurations from
sleep modes with Main Clock running. Only
from BOTHEDGES or LEVEL interrupt sense
configuration from sleep modes with Main
Clock stopped.
previous
Value on pad must be kept until the system
clock has restarted
Datasheet Preliminary
®
megaAVR 0-Series
I/O Pin Configuration (PORT)
Full Asynchronous Sense
Support
Less than a system clock cycle
From all interrupt sense
configurations from all sleep
modes
Less than a system clock cycle
Less than a system clock cycle
DS40002015A-page 141