SMSC LAN9311 User Manual

Two Port 10/100 Managed Ethernet Switch with 16-Bit Non-PCI CPU Interface

Revision 1.4 (08-19-08)

96

SMSC LAN9311/LAN9311i

 

The PHY can also be reset by setting bit 15 (PHY_RST) of the 

. This bit is self clearing and will return to 0 after the reset is complete.

This reset does not reload the configuration strap values into the PHY registers.

After the PHY has returned from a power-down state, a reset of the PHY is automatically generated.
The PHY power-down modes do not reload or reset the PHY registers. Refer to 

 for additional information.

Each PHY provides LED indication signals to the GPIO/LED block of the LAN9311/LAN9311i. This
allows external LEDs to be used to indicate various PHY related functions such as TX/RX activity,
speed, duplex, or link status. Refer to 

 for additional

information on the configuration of these signals.

The magnetics selected for use with the LAN9311/LAN9311i should be an Auto-MDIX style magnetic,
which is widely available from several vendors. Please review the SMSC Application note 8.13
“Suggested Magnetics” for the latest qualified and suggested magnetics. A list of vendors and part
numbers are provided within the application note.

The Virtual PHY provides a basic MII management interface (MDIO) to the Host MAC per the IEEE
802.3 (clause 22) so that an unmodified driver can be supported as if the Host MAC was attached to
a single port PHY. This functionality is designed to allow easy and quick integration of the
LAN9311/LAN9311i into designs with minimal driver modifications. The Virtual PHY provides a full bank
of registers which comply with the IEEE 802.3 specification. This enables the Virtual PHY to provide
various status and control bits similar to those provided by a real PHY. These include the output of
speed selection, duplex, loopback, isolate, collision test, and auto-negotiation status. For a list of all
Virtual PHY registers and related bit descriptions, refer to 

The purpose of the auto-negotiation function is to automatically configure the Virtual PHY to the
optimum link parameters based on the capabilities of its link partner. Because the Virtual PHY has no
actual link partner, the auto-negotiation process is emulated with deterministic results.

Auto-negotiation is enabled by setting bit 12 (VPHY_AN) of the 

 and is restarted by the occurrence of any of the following events:

„

Power-On Reset (POR)

„

Hardware reset (nRST)

„

PHY Software reset (via bit 3 of the 

, bit 0 of the 

, or bit 15 of the 

„

Setting the 

, bit 9 high (auto-neg restart)

„

Digital Reset (via bit 10 of the 

„

Issuing an EEPROM Loader RELOAD command (

)