Техническая Спецификация для Atmel Xplained Pro Evaluation Kit ATSAMD20-XPRO ATSAMD20-XPRO

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Atmel | SMART SAM D20 [DATASHEET]

Atmel-42129K–SAM-D20_datasheet–06/2014

The SERCOM must be configured to the desired mode by writing to the Operating Mode bits in the Control A register 
(CTRLA.MODE). Refer to 

 for details.

For further initialization information, see the respective SERCOM mode chapters.

The SERCOM is enabled by writing a one to the Enable bit in the Control A register (CTRLA.ENABLE). The SERCOM is 
disabled by writing a zero to CTRLA.ENABLE.

The SERCOM is reset by writing a one to the Software Reset bit in the Control A register (CTRLA.SWRST). All registers 
in the SERCOM, except DBGCTRL, will be reset to their initial state, and the SERCOM will be disabled. Refer to the 
CTRLA register descriptions for details.

The baud-rate generator, as shown in 

, is used for internal clock generation for asynchronous and 

synchronous communication. The generated output frequency (f

BAUD

) is determined by the Baud register (BAUD) setting 

and the baud reference frequency (f

REF

). The baud reference clock is the serial engine clock, and it can be internal or 

external.

For asynchronous operation, the /16 (divide-by-16) output is used when transmitting and the /1 (divide-by-1) output is 
used when receiving. For synchronous operation the /2 (divide-by-2) output is used. This functionality is automatically 
configured, depending on the selected operating mode.

0x0

USART with external clock

0x1

USART with internal clock

0x2

SPI in slave operation

0x3

SPI in master operation

0x4

I

2

C slave operation

0x5

I

2

C master operation

0x6-0x7

Reserved