LAN9730 Datasheet, PDF (102/222 Pages) SMSC Corporation – High-Speed Inter-Chip (HSIC) USB 2.0

LAN9730/LAN9730i
4.11 Power States
The following power states are featured.
• NORMAL (Unconfigured and Configured)
• Suspend (SUSPEND0, SUSPEND1, SUSPEND2, and SUSPEND3)
Figure 4-29 illustrates the power states and allowed state transitions.
FIGURE 4-29:
POWER STATES
USB Resume ||
PHY Linkup ||
WOL || GPIO
USB Suspend
SUSPEND0
POR || nRESET ||
USB Reset || SRST
NORMAL
(Unconfigured)
Deconfigured
Configured
NORMAL
(Configured)
USB Resume ||
Energy Detect ||
GPIO
USB Resume ||
USB Suspend ^{PHY Linkup ||}
Frame Rec’d || GPIO
USB Suspend
USB Resume ||
GPIO
USB Suspend
USB Resume ||
GPIO
USB Suspend
SUSPEND1
SUSPEND3
SUSPEND2
Note: It is not possible to transition from SUSPEND2 to NORMAL Configured if SUSPEND2 was entered via a
transition from NORMAL Unconfigured.
4.11.1 NORMAL STATE
The NORMAL state is the fully functional state of the device. The are two flavors of the NORMAL state, NORMAL Con-
figured and NORMAL Unconfigured. In the Configured variation, all chip subsystem modules are enabled. The Uncon-
figured variation has only a subset of the modules enabled. The reduced functionality allows for power savings.
This NORMAL state is entered by any of the following methods:
• A system reset is asserted.
• The device is suspended and the host issues resume signaling.
• The device is suspended and a wake event is detected.
4.11.1.1 Unconfigured
Upon initially entering the NORMAL state, the device is unconfigured. The device transitions to the NORMAL Configured
state upon the host completion of the USB configuration.
It is possible for the device to be deconfigured by the host after being placed in the NORMAL Configured state, via a
set_configuration command. In this case, the CPM must place the device back into the NORMAL Unconfigured state.
4.11.1.2 Reset Operation
After a system reset, the device is placed into the NORMAL Unconfigured state. When in the NORMAL state, the
READY bit in the Power Management Control Register (PMT_CTL) is set. This READY bit is useful to the host after a
USB reset occurs. In this case, it indicates that the values in the EEPROM have been completely loaded.
DS00001946A-page 102
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