If the Early Warning interrupt is enabled in Window mode, the interrupt is generated at the start of the
open window period, i.e. after TO
WDTW
. The Window mode operation is illustrated in figure Window-Mode
Operation.
Figure 24-3. Window-Mode Operation
t [ms]
WDT Count
5
10
15
20
25
30
35
WINDOW[3:0]=0
PER[3:0]=0
Timely WDT Clear
C
lo
se
d
TO
WDTW
O
pe
n
TO
WDT
Early WDT Clear
WDT Timeout
Early Warning Interrupt
24.6.3. DMA Operation
Not applicable.
24.6.4. Interrupts
The WDT has the following interrupt source:
•
Early Warning (EW): Indicates that the counter is approaching the time-out condition.
–
This interrupt is an asynchronous wake-up source.
Each interrupt source has an interrupt flag associated with it. The interrupt flag in the Interrupt Flag Status
and Clear (INTFLAG) register is set when the interrupt condition occurs.
Each interrupt can be individually enabled by writing a '1' to the corresponding bit in the Interrupt Enable
Set (INTENSET) register, and disabled by writing a '1' to the corresponding bit in the Interrupt Enable
Clear (INTENCLR) register.
An interrupt request is generated when the interrupt flag is set and the corresponding interrupt is enabled.
The interrupt request remains active until the interrupt flag is cleared, the interrupt is disabled, or the WDT
is reset. See the
register description for details on how to clear interrupt flags. All interrupt
requests from the peripheral are ORed together on system level to generate one combined interrupt
request to the NVIC. The user must read the INTFLAG register to determine which interrupt condition is
present.
Note:
Interrupts must be globally enabled for interrupt requests to be generated.
Related Links
Nested Vector Interrupt Controller
on page 44
on page 44
on page 191
24.6.5. Events
Not applicable.
Atmel SAM L22G / L22J / L22N [DATASHEET]
Atmel-42402E-SAM L22G / L22J / L22N_Datasheet_Complete-07/2016
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