KSZ8893-MQL Micrel Semiconductor, Inc., KSZ8893-MQL Datasheet - Page 35

• Manufacturer Part Number: KSZ8893-MQL
• Description: Integrated 3-Port 10/100 Managed Switch with PHYs
• Manufacturer: Micrel Semiconductor, Inc.

The SNI interface is a bit wide data interface and therefore runs at the network bit rate (not encoded). An
additional signal on the transmit side indicates when data is valid. Similarly, the receive side has an indicator that
conveys when the data is valid.
For half duplex operation, the SCOL signal is used to indicate that a collision has occurred during transmission.
MII Management (MIIM) Interface
The KSZ8893MQL supports the IEEE 802.3 MII Management Interface, also known as the Management Data
Input/Output (MDIO) Interface. This interface allows upper-layer devices to monitor and control the states of the
KSZ8893MQL. An external device with MDC/MDIO capability is used to read the PHY status or configure the
PHY settings. Further detail on the MIIM interface is found in Clause 22.2.4.5 of the IEEE 802.3u Specification.
The MIIM interface consists of the following:
The MIIM Interface can operate up to a maximum clock speed of 5 MHz.
The following table depicts the MII Management Interface frame format.
Micrel
November 2005
Write
Read
A physical connection that incorporates the data line (MDIO) and the clock line (MDC).
A specific protocol that operates across the aforementioned physical connection that allows an external
Access to a set of eight 16-bit registers, consisting of six standard MIIM registers [0:5] and two custom
controller to communicate with the KSZ8893MQL device.
MIIM registers [29, 31].
Preamble
32 1’s
32 1’s
Start of
Frame
01
01
Table 7. MII Management Interface Frame Format
Read/Write
OP Code
10
01
PHY
Address
Bits [4:0]
AAAAA
AAAAA
35
REG
Address
Bits [4:0]
RRRRR
RRRRR
TA
Z0
10
Data
Bits [15:0]
DDDDDDDD_DDDDDDDD
DDDDDDDD_DDDDDDDD
KSZ8893MQL/MQLI
M9999-111705
Idle
Z
Z