The FPC402 has a single host-side interface which
can be configured as one of two available protocols, depending on the pin strap
value of the PROTOCOL_SEL pin:
Inter-Integrated Circuit
(I2C) up to 1-MHz Fast-mode Plus
Serial Peripheral Interface
(SPI) up to 10 MHz
These represent the two functional modes of operation for which the FPC402 can
be configured. Refer to Section 8.4 for more details.