KSZ8091MLX Datasheet, PDF (15/70 Pages) Micrel Semiconductor – 10Base-T/100Base-TX Physical Layer Transceiver

KSZ8091MLX
3.2.1 MII SIGNAL DEFINITION
Table 3-1 describes the MII signals. Refer to Clause 22 of the IEEE 802.3 Specification for detailed information.
TABLE 3-1: MII SIGNAL DEFINITION
MII Signal
Name
TXC
TXEN
TXD[3:0]
TXER
RXC
RXDV
RXD[3:0]
RXER
CRS
COL
Direction with
Respect to PHY,
KSZ8091MLX
Signal
Output
Input
Input
Input
Output
Output
Output
Output
Output
Output
Direction with
Respect to MAC
Description
Input
Transmit Clock
(2.5 MHz for 10 Mbps; 25 MHz for 100 Mbps)
Output
Transmit Enable
Output
Transmit Data[3:0]
Output or not
implemented
Transmit Error
(KSZ8091MLX implements only the EEE function for this
pin. See Transmit Error (TXER) for details.)
Input
Receive Clock
(2.5 MHz for 10 Mbps; 25 MHz for 100 Mbps)
Input
Receive Data Valid
Input
Receive Data[3:0]
Input or not required Receive Error
Input
Carrier Sense
Input
Collision Detection
3.2.1.1 Transmit Clock (TXC)
TXC is sourced by the PHY. It is a continuous clock that provides the timing reference for TXEN, TXD[3:0], and TXER.
TXC is 2.5 MHz for 10 Mbps operation and 25 MHz for 100 Mbps operation.
3.2.1.2 Transmit Enable (TXEN)
TXEN indicates that the MAC is presenting nibbles on TXD[3:0] for transmission. It is asserted synchronously with the
first nibble of the preamble and remains asserted while all nibbles to be transmitted are presented on the MII. It is
negated before the first TXC following the final nibble of a frame.
TXEN transitions synchronously with respect to TXC.
3.2.1.3 Transmit Data[3:0] (TXD[3:0])
When TXEN is asserted, TXD[3:0] are the data nibbles presented by the MAC and accepted by the PHY for transmis-
sion.
When TXEN is de-asserted, the MAC drives TXD[3:0] to either 0000 for the idle state (non-EEE mode) or 0001 for the
LPI state (EEE mode).
TXD[3:0] transitions synchronously with respect to TXC.
3.2.1.4 Transmit Error (TXER)
TXER is implemented only for the EEE function.
For EEE mode, this pin is driven by the EEE-MAC to put the KSZ8091MLX transmit into the LPI state.
For non-EEE mode, this pin is not defined for error transmission from MAC to KSZ8091MLX and can be left as a no
connect.
TXER transitions synchronously with respect to TXC.
3.2.1.5 Receive Clock (RXC)
RXC provides the timing reference for RXDV, RXD[3:0], and RXER.
In 10 Mbps mode, RXC is recovered from the line while the carrier is active. When the line is idle or the link is down,
RXC is derived from the PHY’s reference clock.
 2016 Microchip Technology Inc.
DS00002297A-page 15