Data Sheet
July 2000
LU6612
FASTCAT Single-FET for 10Base-T/100Base-TX
Pin Information (continued)
Pin Descriptions
Table 1. MII/Serial Interface Pins (17)
Signal
Type Pin
Description
COL
O
43 Collision Detect. This signal signifies in half-duplex mode that a collision has
occurred on the network. COL is asserted high whenever there is transmit and
receive activity on the UTP media. COL is the logical AND of TX_EN and receive
activity, and is an asynchronous output. When SERIAL_SEL (register 30, bit 1) is high
and in 10Base-T mode, this signal indicates the jabber timer has expired. This signal
is held low in full-duplex mode.
CRS
O
O
O
42 Carrier Sense. When CRS_SEL (register 29, bit 10) is low, CRS is asserted high
when either the transmit or receive is nonidle. This signal remains asserted through-
out a collision condition. When CRS_SEL (register 29, bit 10) is high, CRS is
asserted on receive activity only.
RX_CLK
RXD[3:0]
44 Receive Clock. 25 MHz clock output in 100 Mbits/s mode, 2.5 MHz output in
10 Mbits/s nibble mode, 10 MHz in 10 Mbits/s serial mode. RX_CLK has a worst-case
45/55 duty cycle. RX_CLK provides the timing reference for the transfer of RX_DV,
RXD, and RX_ER signals.
37:40 Receive Data. 4-bit parallel data outputs that are synchronous to the falling edge of
RX_CLK. When RX_ER is asserted high in 100 Mbits/s mode, an error code will be
presented on RXD[3:0] where appropriate. The codes are as follows:
■ Packet errors: ERROR_CODES = 2h;
■ Link errors: ERROR_CODES = 3h (Packet and link error codes will only be
repeated if registers [29.9] and [29.8] are enabled.);
■ Premature end errors: ERROR_CODES = 4h;
■ Code errors: ERROR_CODES = 5h.
When SERIAL_SEL (register 30, bit 1) is active-high and 10 Mbits/s mode is selected,
RXD[0] is used for data output and RXD[3:1] are 3-stated.
RX_DV
O
O
45 Receive Data Valid. When this pin is high, it indicates the LU6612 is recovering and
decoding valid nibbles on RXD[3:0], and the data is synchronous with RX_CLK.
RX_DV is synchronous with RX_CLK. This pin is not used in serial 10 Mbits/s mode.
RX_ER/
RXD[4]
46 Receive Error. When high, RX_ER indicates the LU6612 has detected a coding error
in the frame presently being transferred. RX_ER is synchronous with RX_CLK. When
the encode/decode bypass (EDB) is selected through the MII management interface,
this output serves as the RXD[4] output. This pin is only valid when LU6612 is in
100 Mbits/s mode.
TX_CLK
O
47 Transmit Clock. 25 MHz clock output in 100 Mbits/s mode, 2.5 MHz output in
10 Mbits/s MII mode, 10 MHz output in 10 Mbits/s serial mode. TX_CLK provides tim-
ing reference for the transfer of the TX_EN, TXD, and TX_ER signals. These signals
are sampled on the rising edge of TX_CLK.
TXD[3:0]
TX_EN
I
I
31:34 Transmit Data. 4-bit parallel input synchronous with TX_CLK. When SERIAL_SEL
(register 30, bit 1) is active-high and 10 Mbits/s mode is selected, only TXD[0] is valid.
30 Transmit Enable. When driven high, this signal indicates there is valid data on
TXD[3:0]. TX_EN is synchronous with TX_CLK. When SERIAL_SEL
(register 30, bit 1) is active-high and 10 Mbits/s mode is selected, this pin indicates
there is valid data on TXD[0].
Lucent Technologies Inc.
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