KS8999_11 MICREL [Micrel Semiconductor], KS8999_11 Datasheet - Page 23

• Manufacturer Part Number: KS8999_11
• Description: Integrated 9-Port 10/100 Switch with PHY and Frame Buffer
• Manufacturer: MICREL [Micrel Semiconductor]

January 2005
Micrel, Inc.
MII Interface Operation
The MII (Media Independent Interface) operates in either a MAC or PHY mode. In the MAC mode, the KS8999 MII
acts like a MAC and in the PHY mode, it acts like a PHY device. This interface is specified by the IEEE 802.3
committee and provides a common interface between physical layer and MAC layer devices. There are two distinct
groups, one being for transmission and the other for receiving. The table below describes the signals used in this
interface in MAC and PHY modes.
This interface is a nibble wide data interface and therefore runs at _ the network bit rate (not encoded). Additional
signals on the transmit side indicate when data is valid or when an error occurs during transmission. Likewise, the
receive side has indicators that convey when the data is valid and without physical layer errors.
For half-duplex operation there is a signal that indicates a collision has occurred during transmission.
Controller Signals
External MAC
MRXDV
MRXER
MTXEN
MTXER
MTXD3
MTXD2
MTXD1
MTXD0
MRXD3
MRXD2
MRXD1
MRXD0
MCOL
MCRS
MRXC
MTXC
PHY Mode Connection
KS8999 PHY
Not used
MRXD[3]
MRXD[2]
MRXD[1]
MRXD[0]
MTXD[3]
MTXD[2]
MTXD[1]
MTXD[0]
MRXDV
Signals
MTXEN
MTXER
MTXC
MCOL
MCRS
MRXC
Description
Transmit enable
Transmit error
Transmit data bit 3
Transmit data bit 2
Transmit data bit 1
Transmit data bit 0
Transmit clock
Collision detection
Carrier sense
Receive data valid
Receive error
Receive data bit 3
Receive data bit 2
Receive data bit 1
Receive data bit 0
Receive clock
Table 1. MII Signals
23
External PHY
MRXDV
MRXER
Signals
MTXEN
MTXER
MRXD3
MRXD2
MRXD1
MRXD0
MTXD3
MTXD2
MTXD1
MTXD0
MCOL
MCRS
MRXC
MTXC
MAC Mode Connection
KS8999 MAC Signals
SMTXEN
MRXD[3]
MRXD[2]
MRXD[1]
MRXD[0]
Not used
MTXD[3]
MTXD[2]
MTXD[1]
MTXD[0]
MRXDV
MTXER
MCOL
MCRS
MRXC
MTXC
KS8999
KS8999