The USB2504 4-port hub controller is fully compliant with the USB 2.0 Specification and does not require firmware development. When connected to a USB high-speed host, the four downstream ports can operate at low-speed (1.5Mb/s), full-speed (12Mb/s), or high-speed (480Mb/s). As required by the USB 2.0 Specification, the USB2504 is fully backward compatible with legacy USB full-speed hosts. A default configuration is available in the USB2504 following a reset. This configuration may be sufficient for some applications when it is desired to save the expense of an EEPROM. The controller may be configured from a microcontroller or an external EEPROM. When using the microcontroller interface, the USB2504 appears as a SMBus slave device. The EEPROM interface supports a 2-wire I²C device. All required resistors on the USB ports are integrated into the USB2504. This includes all series termination resistors on D+ and D- pins and all required pull-down and pull-up resistors on D+ and D- pins. The over-current sense inputs for the downstream ports have internal pull-up resistors. *The USBCheck online design review service is subject to Microchip's Program Terms and Conditions and requires a myMicrochip account.