SPI Frame Formats

The serial frame in SPI mode is defined to be one character of eight data bits. The USART in master SPI mode has two valid frame formats:

The data order is selected by writing to the Data Order bit (UDORD) in the Control C register (USART.CTRLC).

After a complete frame is transmitted, a new frame can directly follow it, or the communication line can return to the idle (high) state.