LAN9500AI datasheet(45/66 Pages) SMSC

45 / 66 page

USB 2.0 to 10/100 Ethernet Controller

Datasheet

SMSC LAN950x Family

Revision 1.1 (04-18-13)

DATASHEET

Chapter 7 NetDetach Operation

NetDetach operation is supported only by LAN9500A/LAN9500Ai

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 APCI 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. GPIO pin assertion

is supported so that this feature can be used with external PHY mode. In this case, the external PHY’s

link LED would be connected to a GPIO.

Figure 7.1 Device Detach

USB Electricals Detach

Remove Ethernet Cable

...ZZZ

Battery-powered Netbook PC

may enter C3 sleep mode

Ethernet

SMSC

LAN9500A/

LAN9500Ai

LAN9500AI 数据表(PDF) 45 Page - SMSC Corporation