Nested Vector Interrupt Controller
on page 44
42.6.13. Events
The AC can generate the following output events:
•
Comparator (COMP0, COMP1): Generated as a copy of the comparator status
•
Window (WIN0): Generated as a copy of the window inside/outside status
Writing a one to an Event Output bit in the Event Control Register (EVCTRL.xxEO) enables the
corresponding output event. Writing a zero to this bit disables the corresponding output event. Refer to
the Event System chapter for details on configuring the event system.
The AC can take the following action on an input event:
•
Start comparison (START0, START1): Start a comparison.
Writing a one to an Event Input bit into the Event Control register (EVCTRL.COMPEIx) enables the
corresponding action on input event. Writing a zero to this bit disables the corresponding action on input
event. Note that if several events are connected to the AC, the enabled action will be taken on any of the
incoming events. Refer to the Event System chapter for details on configuring the event system.
When EVCTRL.COMPEIx is one, the event will start a comparison on COMPx after the start-up time
delay. In normal mode, each comparator responds to its corresponding input event independently. For a
pair of comparators in window mode, either comparator event will trigger a comparison on both
comparators simultaneously.
42.6.14. Sleep Mode Operation
The Run in Standby bits in the Comparator x Control registers (COMPCTRLx.RUNSTDBY) control the
behavior of the AC during standby sleep mode. Each RUNSTDBY bit controls one comparator. When the
bit is zero, the comparator is disabled during sleep, but maintains its current configuration. When the bit is
one, the comparator continues to operate during sleep. Note that when RUNSTDBY is zero, the analog
blocks are powered off for the lowest power consumption. This necessitates a start-up time delay when
the system returns from sleep.
For Window Mode operation, both comparators in a pair must have the same RUNSTDBY configuration.
When RUNSTDBY is one, any enabled AC interrupt source can wake up the CPU. The AC can also be
used during sleep modes where the clock used by the AC is disabled, provided that the AC is still
powered (not in shutdown). In this case, the behavior is slightly different and depends on the
measurement mode, as listed in
.
Table 42-1. Sleep Mode Operation
COMPCTRLx.MODE RUNSTDBY=0
RUNSTDBY=1
0 (Continuous)
COMPx disabled GCLK_AC stopped, COMPx enabled
1 (Single-shot)
COMPx disabled GCLK_AC stopped, COMPx enabled only when triggered by
an input event
42.6.14.1. Continuous Measurement during Sleep
When a comparator is enabled in continuous measurement mode and GCLK_AC is disabled during
sleep, the comparator will remain continuously enabled and will function asynchronously. The current
state of the comparator is asynchronously monitored for changes. If an edge matching the interrupt
condition is found, GCLK_AC is started to register the interrupt condition and generate events. If the
interrupt is enabled in the Interrupt Enable registers (INTENCLR/SET), the AC can wake up the device;
Atmel SAM L22G / L22J / L22N [DATASHEET]
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