USART Operation: SPI Mode

15-10 USART Peripheral Interface, SPI Mode

Serial Clock Polarity and Phase

The polarity and phase of UCLK are independently configured via the CKPL

and CKPH control bits of the USART. Timing for each case is shown in

Figure 159.

Figure 159. USART SPI Timing
CKPH CKPL Cycle#
UCLK
UCLK
UCLK
UCLK
SIMO/
SOMI
SIMO/
SOMI
Move to UxTXBUF
RX Sample Points
0
1
0
0
01
11
0X
1X
MSB
MSB
12345678
LSB
LSB
TX Data Shifted Out
STE