The host controller provides a two-wire serial-bus interface to load subsystem identification information and specific register defaults from an external EEPROM. The serial-bus interface signals include SDA and SCL. The use of an external EEPROM is optional. The TUSB73x0 will function with the default settings.  For motherboard down applications, BIOS can be used to set all of the options available on the TUSB73x0.

On a PCIe Add-in Card, an EEPROM is only needed if any of the following is true:

• Mark one or more USB ports as non-removable.
• Disable one or more USB ports.
• Set a PCIe Subsystem ID and Subsystem Vendor ID.
• Change the default de-emphasis/swing/equalizer settings of the SuperSpeed USB ports.
• Change the default L0s and L1 latency values for PCIe.
• Change the default PWRON polarity to active high instead of active low.