Atmel Xplained Pro Evaluation Kit for the ATSAMD21J18A Microcontroller ATSAMD21-XPRO ATSAMD21-XPRO Data Sheet
Product codes
ATSAMD21-XPRO
427
Atmel | SMART SAM D21 [DATASHEET]
Atmel-42181C–SAM-D21_Datasheet–07/2014
24.6.5 Interrupts
Interrupt sources are mode-specific. See the respective SERCOM mode chapters for details.
Each interrupt source has an interrupt flag associated with it. The interrupt flag in the Interrupt Flag Status and Clear
register (INTFLAG) is set when the interrupt condition occurs. Each interrupt can be individually enabled by writing a one
to the corresponding bit in the Interrupt Enable Set register (INTENSET), and disabled by writing a one to the
corresponding bit in the Interrupt Enable Clear register (INTENCLR). 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 SERCOM is reset. See the register description for details on how to clear interrupt
flags.
register (INTFLAG) is set when the interrupt condition occurs. Each interrupt can be individually enabled by writing a one
to the corresponding bit in the Interrupt Enable Set register (INTENSET), and disabled by writing a one to the
corresponding bit in the Interrupt Enable Clear register (INTENCLR). 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 SERCOM is reset. See the register description for details on how to clear interrupt
flags.
The SERCOM has one common interrupt request line for all the interrupt sources. The user must read the INTFLAG
register to determine which interrupt condition is present.
register to determine which interrupt condition is present.
Note that interrupts must be globally enabled for interrupt requests to be generated. Refer to
24.6.6 Events
Not applicable.
24.6.7 Sleep Mode Operation
The peripheral can operate in any sleep mode where the selected serial clock is running. This clock can be external or
generated by the internal baud-rate generator.
generated by the internal baud-rate generator.
The SERCOM interrupts can be used to wake up the device from sleep modes. Refer to the different SERCOM mode
chapters for details.
chapters for details.
24.6.8 Synchronization
Due to the asynchronicity between CLK_SERCOMx_APB and GCLK_SERCOMx_CORE, some registers must be
synchronized when accessed. A register can require:
synchronized when accessed. A register can require:
z
Synchronization when written
z
Synchronization when read
z
Synchronization when written and read
z
No synchronization
When executing an operation that requires synchronization, the Synchronization Busy bit in the Status register
(STATUS.SYNCBUSY) will be set immediately, and cleared when synchronization is complete. The Synchronization
Ready interrupt can be used to signal when synchronization is complete.
(STATUS.SYNCBUSY) will be set immediately, and cleared when synchronization is complete. The Synchronization
Ready interrupt can be used to signal when synchronization is complete.
If an operation that requires synchronization is executed while STATUS.SYNCBUSY is one, the bus will be stalled. All
operations will complete successfully, but the CPU will be stalled and interrupts will be pending as long as the bus is
stalled.
operations will complete successfully, but the CPU will be stalled and interrupts will be pending as long as the bus is
stalled.