Lucent Technologies Inc.
9
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
COL
Type
O
Pin
43
Description
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.
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.
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:
I
Packet errors: ERROR_CODES = 2h;
I
Link errors: ERROR_CODES = 3h (Packet and link error codes will only be
repeated if registers [29.9] and [29.8] are enabled.);
I
Premature end errors: ERROR_CODES = 4h;
I
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.
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.
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.
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.
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].
CRS
O
42
RX_CLK
O
44
RXD[3:0]
O
RX_DV
O
RX_ER/
RXD[4]
O
TX_CLK
O
TXD[3:0]
I
TX_EN
I