SPI

SPI or Sam Parallel Interface (later 'Sam's Printer Interface' reflecting the change of functionality) provides a standard parallel interface similar to the Comms Interface.

Version 1 claimed to have a bi-directional parallel interface however only one direction at a time could be accomodated so for full-duplex operation two devices with a SamBus would need to be used.

Version 2 was the same PCB as the Comms Interface but without a serial componants so lacked the bi-directional facility.