disabled, or the USART is reset. For details on clearing interrupt flags, refer to the INTFLAG register
description.
The USART has one common interrupt request line for all the interrupt sources. The value of INTFLAG
indicates which interrupt is executed. Note that interrupts must be globally enabled for interrupt requests.
Refer to
Nested Vector Interrupt Controller
for details.
Related Links
Nested Vector Interrupt Controller
on page 44
32.6.4.3. Events
Not applicable.
32.6.5. Sleep Mode Operation
The behavior in sleep mode is depending on the clock source and the Run In Standby bit in the Control A
register (CTRLA.RUNSTDBY):
•
Internal clocking, CTRLA.RUNSTDBY=1: GCLK_SERCOMx_CORE can be enabled in all sleep
modes. Any interrupt can wake up the device.
•
External clocking, CTRLA.RUNSTDBY=1: The Receive Complete interrupt(s) can wake up the
device.
•
Internal clocking, CTRLA.RUNSTDBY=0: Internal clock will be disabled, after any ongoing transfer
was completed. The Receive Complete interrupt(s) can wake up the device.
•
External clocking, CTRLA.RUNSTDBY=0: External clock will be disconnected, after any ongoing
transfer was completed. All reception will be dropped.
32.6.6. Synchronization
Due to asynchronicity between the main clock domain and the peripheral clock domains, some registers
need to be synchronized when written or read.
The following bits are synchronized when written:
•
Software Reset bit in the CTRLA register (CTRLA.SWRST)
•
Enable bit in the CTRLA register (CTRLA.ENABLE)
•
Receiver Enable bit in the CTRLB register (CTRLB.RXEN)
•
Transmitter Enable bit in the Control B register (CTRLB.TXEN)
Note:
CTRLB.RXEN is write-synchronized somewhat differently. See also
for details.
Required write-synchronization is denoted by the "Write-Synchronized" property in the register
description.
Atmel SAM L22G / L22J / L22N [DATASHEET]
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