Three Port 10/100 Managed Ethernet Switch with MII
Datasheet
Chapter 7 Ethernet PHYs
7.1
Functional Overview
The LAN9313/LAN9313i contains three PHYs: Port 1 PHY, Port 2 PHY and a Virtual PHY. The Port 1
& 2 PHYs are identical in functionality and each connect their corresponding Ethernet signal pins to
the switch fabric MAC of their respective port. These PHYs interface with their respective MAC via an
internal MII interface. The Virtual PHY provides the virtual functionality of a PHY and allows connection
of an external MAC to port 0 of the switch fabric as if it was connected to a single port PHY. All PHYs
comply with the IEEE 802.3 Physical Layer for Twisted Pair Ethernet and can be configured for full/half
duplex 100 Mbps (100BASE-TX) or 10Mbps (10BASE-T) Ethernet operation. All PHY registers follow
the IEEE 802.3 (clause 22.2.4) specified MII management register set and can be configured indirectly
via the external MII interface signals, or directly via the memory mapped Virtual PHY registers. In
addition, the Port 1 PHY and Port 2 PHY can be configured via the PHY Management Interface (PMI).
Refer to Section 13.2, "Ethernet PHY Control and Status Registers" for details on the Ethernet PHY
registers.
The LAN9313/LAN9313i Ethernet PHYs are discussed in detail in the following sections:
Section 7.2, "Port 1 & 2 PHYs," on page 85
Section 7.3, "Virtual PHY," on page 98
7.1.1
PHY Addressing
Each individual PHY is assigned a unique default PHY address via the phy_addr_sel_strap
configuration strap as shown in Table 7.1. In addition, the Port 1 PHY and Port 2 PHY addresses can
be changed via the PHY Address (PHYADD) field in the Port x PHY Special Modes Register
(PHY_SPECIAL_MODES_x). For proper operation, all LAN9313/LAN9313i PHY addresses must be
unique. No check is performed to assure each PHY is set to a different address. Configuration strap
values are latched upon the de-assertion of a chip-level reset as described in Section 4.2.4,
"Configuration Straps," on page 45.
Table 7.1 Default PHY Serial MII Addressing
VIRTUAL PHY DEFAULT
ADDRESS VALUE
PORT 1 PHY DEFAULT PORT 2 PHY DEFAULT
PHY_ADDR_SEL_STRAP
ADDRESS VALUE
ADDRESS VALUE
0
1
0
1
1
2
2
3
Revision 1.2 (04-08-08)
SMSC LAN9313/LAN9313i
DATA8S4HEET
SMSC [ SMSC CORPORATION ]
