The USART in Host SPI mode is fully compatible with a stand-alone SPI peripheral. Their
data frame and timing configurations are identical. Some SPI specific special features are,
however, not supported with the USART in Host SPI mode:
- Write Collision Flag Protection
- Double-Speed mode
- Multi-Host support
A comparison of the pins used with USART
in Host SPI mode and with SPI is shown in the table below.
Table 1. Comparison of USART in Host SPI
Mode and SPI Pins
| USART |
SPI |
Comment |
| TXD |
MOSI |
Host
out |
| RXD |
MISO |
Host
in |
| XCK |
SCK |
Functionally
identical |
| - |
SS |
Not supported
by USART in Host SPI mode(1) |
Note:
- 1.For the stand-alone SPI peripheral,
this pin is used with the Multi-Host function or as a dedicated Client Select pin.
The Multi-Host function is not available with the USART in Host SPI mode, and no
dedicated Client Select pin is available.