Datasheet

629
32117D–AVR-01/12
AT32UC3C
• INACK: Inhibit Non Acknowledge
0: The NACK is generated.
1: The NACK is not generated.
Note: in SPI master mode, if INACK = 0 the character transmission starts as soon as character is written into THR register
(assuming TXRDY was set). When INACK = 1, an additional condition must be met. The character transmission starts when a
character is written and only if RXRDY bit is cleared (RHR has been read).
• OVER: Oversampling Mode
0: 16x Oversampling.
1: 8x Oversampling.
• CLKO: Clock Output Select
0: The USART does not drive the CLK pin.
1: The USART drives the CLK pin if USCLKS does not select the external clock CLK.
• MODE9: 9-bit Character Length
0: CHRL defines character length.
1: 9-bit character length.
• MSBF/CPOL: Bit Order or SPI Clock Polarity
If USART does not operate in SPI Mode (MODE … 0xE and 0xF):
MSBF = 0: Least Significant Bit is sent/received first.
MSBF = 1: Most Significant Bit is sent/received first.
If USART operates in SPI Mode (Slave or Master, 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.
• CHMODE: Channel Mode
• NBSTOP: Number of Stop Bits
Table 25-17.
CHMODE Mode Description
0 0 Normal Mode
0 1 Automatic Echo. Receiver input is connected to the TXD pin.
1 0 Local Loopback. Transmitter output is connected to the Receiver Input.
1 1 Remote Loopback. RXD pin is internally connected to the TXD pin.
Table 25-18.
NBSTOP Asynchronous (SYNC = 0) Synchronous (SYNC = 1)
0 0 1 stop bit 1 stop bit
0 1 1.5 stop bits Reserved
1 0 2 stop bits 2 stop bits
1 1 Reserved Reserved