Three Port 10/100 Managed Ethernet Switch with MII
Datasheet
9.4
MII Mode Multiplexer
The MII mode multiplexer is used to direct the MII data/management path connections. One master
(MAC via the MII pins, or PMI) is connected to the slaves (PHY via MII pins, Port 1/2 PHYs, Virtual
PHY, and SMI slave) dependant on the selected management mode of the LAN9313/LAN9313i. The
MII mode multiplexer also performs the multiplexing of the read data signals from the slaves and
controls the output enable of the MII pins.
The following sections detail the operation of the MII mode multiplexer in each management mode. A
list of management modes and their configuration settings are discussed in Section 2.3, "Modes of
Operation," on page 23.
9.4.1
MAC Mode Unmanaged
In MAC mode unmanaged, no external accesses to the LAN9313/LAN9313i are required. The MII
multiplexer is disabled and the MII management pins are not driven.
The Virtual PHY interface is accessible via the EEPROM Loader. Refer to Section 8.2.4, "EEPROM
Loader," on page 113 for additional information.
Figure 9.1 details the MII multiplexer management path connections for this mode.
MII Pins
MDIO_DIR
MDI
SMI Slave
MDO
MDO
MDIO_DIR
MDIO
MDC
Parallel
Master
MDCLK
MDI
MDC_DIR
MDC_OUT
MDC_IN
MDI
Virtual PHY
MDO
Management
Mode Selection
MDIO_DIR
Parallel
Slave
MDCLK
MDI
PHY2
MDO
MDIO_DIR
MDCLK
MDI
PHY1
MDO
MDIO_DIR
MDCLK
Management
Mode Selection
MDO MDCLK MDI MDO_EnN
PMI
Parallel Slave
Figure 9.1 MII Mux Management Path Connections - MAC Mode Unmanaged
Revision 1.2 (04-08-08)
128
SMSC LAN9313/LAN9313i
DATASHEET
SMSC [ SMSC CORPORATION ]
