Atmel ARM-Based Evaluation Kit AT91SAM9N12-EK AT91SAM9N12-EK データシート

811

SAM9N12/SAM9CN11/SAM9CN12 [DATASHEET]

11063K–ATARM–05-Nov-13

Applicable if USART operates in SPI Mode (Slave or Master, USART_MODE = 0xE or 0xF):

0: The inactive state value of SPCK is logic level zero.

1: The inactive state value of SPCK is logic level one.

CPOL is used to determine the inactive state value of the serial clock (SPCK). It is used with CPHA to produce the required 
clock/data relationship between master and slave devices.

0: The character transmission starts as soon as a character is written into US_THR register (assuming TXRDY was set).

1: The character transmission starts when a character is written and only if RXRDY flag is cleared (Receiver Holding Register has 
been read).

0

NORMAL

Normal Mode

1

AUTOMATIC

Automatic Echo. Receiver input is connected to the TXD pin. 

2

LOCAL_LOOPBACK

Local Loopback. Transmitter output is connected to the Receiver Input.

3

REMOTE_LOOPBACK

Remote Loopback. RXD pin is internally connected to the TXD pin.