USART in SPI Host Mode vs. SPI

The USART in SPI Host mode is fully compatible with a stand-alone SPI peripheral as their data frame and timing configurations are identical. However, some SPI-specific special features are not supported when using the USART in SPI Host mode:
  • Write Collision Flag Protection
  • Double-Speed mode
  • Multi-Host support

A comparison of the pins used by the USART in SPI Host mode and by a stand-alone SPI peripheral is shown in the table below.

Table 25-3. Comparison of USART in SPI Host Mode and SPI Pins
USARTSPIComment
TXDMOSIHost out
RXDMISOHost in
XCKSCKFunctionally identical
-SSNot supported by USART in SPI Host mode(1)
Note:
  1. For a stand-alone SPI peripheral, this pin is used for the Multi-Host function or as a dedicated Client Select pin. The Multi-Host function is not available with the USART in SPI Host mode, and there is no dedicated Client Select pin.