WJLXT972MLC.A4 S L7U9 Intel, WJLXT972MLC.A4 S L7U9 Datasheet - Page 50

• Manufacturer Part Number: WJLXT972MLC.A4 S L7U9
• Manufacturer: Intel

Specifications of WJLXT972MLC.A4 S L7U9

• Lead Free Status / RoHS Status: Compliant

Intel
5.8
5.8.1
5.8.2
5.8.3
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®
LXT972M Single-Port 10/100 Mbps PHY Transceiver
Note:
10 Mbps Operation
The LXT972M Transceiver operates as a standard 10BASE-T transceiver and supports standard
10 Mbps functions. During 10BASE-T operation, the LXT972M Transceiver transmits and
receives Manchester-encoded data across the network link. When the MAC is not actively
transmitting data, the LXT972M Transceiver drives link pulses onto the line.
In 10BASE-T mode, the polynomial scrambler/de-scrambler is inactive. Manchester-encoded
signals received from the network are decoded by the LXT972M Transceiver and sent across the
MII to the MAC.
10BASE-T Preamble Handling
The LXT972M Transceiver offers two options for preamble handling, selected by Register bit 16.5.
10BASE-T Carrier Sense
For 10BASE-T links, CRS assertion is based on reception of valid preamble, and CRS de-assertion
is based on reception of an end-of-frame (EOF) marker. Register bit 16.7 allows CRS de-assertion
to be synchronized with RX_DV de-assertion. For details, see
Address 16, Hex 10” on page
10BASE-T Dribble Bits
The LXT972M Transceiver handles dribble bits in all modes. If one to four dribble bits are
received, the nibble is passed across the MII, padded with ones if necessary. If five to seven
dribble bits are received, the second nibble is not sent to the MII bus.
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•
In 10BASE-T mode when Register bit 16.5 = 0, the LXT972M Transceiver strips the entire
preamble off of received packets. CRS is asserted coincident with the start of the preamble.
RX_DV is held Low for the duration of the preamble. When RX_DV is asserted, the very first
two nibbles driven by the LXT972M Transceiver are the SFD “5D” hex followed by the body
of the packet.
In 10BASE-T mode when Register bit 16.5 = 1, the LXT972M Transceiver passes the
preamble through the MII and asserts RX_DV and CRS simultaneously. (In 10BASE-T
loopback, the LXT972M Transceiver loops back whatever the MAC transmits to it, including
the preamble.)
84.
Table 51, “Configuration Register -
Document Number: 302875-005
Revision Date: 27-Oct-2005
Datasheet