The SC18IS600/601 is designed to serve as an interface between the standard SPI of a host (microcontroller, microprocessor, chip set, etc.) and the serial I2C-bus. This allows the host to communicate directly with other I2C-bus devices. The SC18IS600/601 can operate as an I2C-bus master-transmitter or master-receiver. The SC18IS600/601 controls all the I2C-bus specific sequences, protocol, arbitration and timing. The key distinction between the SC18IS600 and the SC18IS601 lies in the clock source: internal (SC18IS600) versus external (SC18IS601).