Atmel Xplained Pro Evaluation Kit for the ATSAMD21J18A Microcontroller ATSAMD21-XPRO ATSAMD21-XPRO Data Sheet

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Atmel | SMART SAM D21 [DATASHEET]

Atmel-42181C–SAM-D21_Datasheet–07/2014

Registers can be 8, 16, or 32 bits wide. Atomic 8-, 16-, and 32-bit accesses are supported. In addition, the 8-bit quarters 
and 16-bit halves of a 32-bit register, and the 8-bit halves of a 16-bit register can be accessed directly.

Some registers are optionally write-protected by the Peripheral Access Controller (PAC). Write-protection is denoted by 
Write-Protected property in each individual register description. Refer to 

 for details.

Some registers require synchronization when read and/or written. Synchronization is denoted by the Write-Synchronized 
or the Read-Synchronized property in each individual register description. Refer to 

 for 

details.

Some registers are enable-protected, meaning they can only be written when the I

2

S is disabled. Enable-protection is 

denoted by the Enable-Protected property in each individual register description.