A system reset forces the SPI peripheral into the following default configuration:
- Unit is configured as a peripheral module (CONTROLLER_PERIPHERAL = 0)
- Transmit capability is disabled (TALK = 0)
- Data is latched at the input on the falling edge of the SPICLK signal
- Character length is assumed to be one bit
- SPI interrupts are disabled
- Data in SPIDAT is reset to 0000h