Datasheet

822
SAM9G15 [DATASHEET]
11052D–ATARM–31-Oct-12
• CHMODE: Channel Mode
• CPOL: SPI Clock Polarity
– Applicable if USART operates in SPI Mode (Slave or Master, USART_MODE = 0xE or 0xF):
CPOL = 0: The inactive state value of SPCK is logic level zero.
CPOL = 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.
• WRDBT: Wait Read Data Before Transfer
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).
Value Name Description
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.