USART SPI vs. SPI

The USART in master SPI mode is fully compatible with the standalone SPI module in that:

When the USART is set in master SPI mode, configuration and use are in some cases different from those of the standalone SPI module. In addition, the following difference exists:

The USART in master SPI mode does not include the SPI double speed mode feature, but this can be achieved by configuring the baud rate generator accordingly:

A comparison of the USART in master SPI mode and the SPI pins is shown in Table 1.

Table 1. Comparison of USART in master SPI mode and SPI pins.
USART SPI Comment
TxD MOSI Master out only
RxD MISO Master in only
XCK SCK Functionally identical
- SS Not supported by USART in master SPI mode