USB 2.0 Hi-Speed 3-Port Hub Controller Optimized for Portable Applications
Datasheet
the operating mode is changed by the system. The only device registers accessible to the SOC are
the run time registers described in Section 7.3.1, "SMBus Run Time Accessible Registers," on page 35.
If RESET_N is asserted low, then Standby Mode is entered. The device may then be placed into any
of the designated Hub stages. Asserting the soft disconnect on the upstream port will cause the Hub
to return to the Hub.Connect stage until the soft disconnect is negated. If the HUB_CONN pin
transitions from asserted to negated, the device will return to the Hub.Connect stage.
To save power, communication over the SMBus is not supported while in USB Suspend. The system
can, however, command the device to wake up by the asserting the IRQ_N pin. The system can
prevent the device from going to sleep by asserting the ClkSusp control bit of the Configure Portable
Hub Register anytime before entering USB Suspend. While the device is kept awake during USB
Suspend, it will provide the SMBus functionality at the expense of not meeting USB requirements for
average suspend current consumption.
SMSC USB3813
23
Revision 1.0 (06-17-13)
DATASHEET
SMSC [ SMSC CORPORATION ]
