Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK Data Sheet

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SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]

11063K–ATARM–05-Nov-13

The pins used for interfacing the USART may be multiplexed with the PIO lines. The programmer must first program the
PIO controller to assign the desired USART pins to their peripheral function. If I/O lines of the USART are not used by the
application, they can be used for other purposes by the PIO Controller.

To prevent the TXD line from falling when the USART is disabled, the use of an internal pull up is mandatory. If the
hardware handshaking feature  is used, the internal pull up on TXD must also be enabled.

SCK

Serial Clock

I/O

—

TXD

Transmit Serial Data

or Master Out Slave In (MOSI) in SPI Master Mode

or Master In Slave Out (MISO) in SPI Slave Mode

I/O

—

RXD

Receive Serial Data

or Master In Slave Out (MISO) in SPI Master Mode

or Master Out Slave In (MOSI) in SPI Slave Mode

Input

—

CTS

Clear to Send

or Slave Select (NSS) in SPI Slave Mode

Input

Low

RTS

Request to Send

or Slave Select (NSS) in SPI Master Mode

Output

Low

USART0

CTS0

PA3

A

USART0

RTS0

PA2

A

USART0

RXD0

PA1

A

USART0

SCK0

PA4

A

USART0

TXD0

PA0

A

USART1

CTS1

PC28

C

USART1

RTS1

PC27

C

USART1

RXD1

PA6

A

USART1

SCK1

PC29

C

USART1

TXD1

PA5

A

USART2

CTS2

PB1

B

USART2

RTS2

PB0

B

USART2

RXD2

PA8

A

USART2

SCK2

PB2

B

USART2

TXD2

PA7

A