Hi-Speed USB 2.0 to 10/100/1000 Ethernet Controller
Datasheet
Chapter 5 NetDetach Operation
5.1
NetDetach
NetDetach is a mode of operation where the device detaches from the USB bus after the Ethernet
cable is disconnected. This is advantageous for mobile devices, as an attached USB device may
prevent the Host CPU from entering the ACPI C3 state. Allowing the CPU to enter the C3 state
maximizes battery life, as the C3 state is the lowest of the four APCI power states.
When detached, the device is in a low power state. After the Ethernet cable is reconnected, or a
programmed GPIO pin asserts, the device automatically attaches to the USB bus.
Ethernet
Remove Ethernet Cable
1
SMSC
LAN7500/
LAN7500i
USB Electricals Detach
2
3
Battery-powered Netbook PC
may enter C3 sleep mode
...ZZZ
Figure 5.1 LAN7500/LAN7500i Detach
Revision 1.0 (11-01-10)
SMSC LAN7500/LAN7500i
DATA3S4HEET
SMSC [ SMSC CORPORATION ]
