WJLXT971ALE.A4-857346 Cortina Systems Inc, WJLXT971ALE.A4-857346 Datasheet - Page 46

• Manufacturer Part Number: WJLXT971ALE.A4-857346
• Manufacturer: Cortina Systems Inc

Specifications of WJLXT971ALE.A4-857346

• Lead Free Status / RoHS Status: Compliant

LXT971A PHY
Datasheet
249414, Revision 5.2
13 September 2007
5.7.3.1.1
Table 15
Cortina Systems
Preamble Handling
When the MAC asserts TX_EN, the PCS substitutes a /J/K symbol pair, also known as the
Start-of-Stream Delimiter (SSD), for the first two nibbles received across the MII. The PCS
layer continues to encode the remaining MII data, following the 4B/5B coding in
until TX_EN is de-asserted. It then returns to supplying IDLE symbols to the line driver.
In the receive direction, the PCS layer performs the opposite function, substituting two
preamble nibbles for the SSD. In 100 Mbps operation, preamble is always passed through
the PCS layer to the MII interface.
4B/5B Coding (Sheet 1 of 2)
®
1. The /I/ (Idle) code group is sent continuously between frames.
2. The /J/ and /K/ (SSD) code groups are always sent in pairs, and /K/ follows /J/.
3. The /T/ and /R/ (ESD) code groups are always sent in pairs, and /R/ follows /T/.
4. An /H/ (Error) code group is used to signal an error condition.
Code Type
CONTROL
LXT971A Single-Port 10/100 Mbps PHY Transceiver
DATA
IDLE
Undefined
Undefined
undefined
4B Code
3 2 1 0
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
0 1 0 1
0 1 0 1
Name
R
K
T
J
I
C
D
0
1
2
3
4
5
6
7
8
9
A
B
E
F
1
2
2
3
3
4 3 2 1 0
5B Code
1 1 1 1 0
0 1 0 0 1
1 0 1 0 0
1 0 1 0 1
0 1 0 1 0
0 1 0 1 1
0 1 1 1 0
0 1 1 1 1
1 0 0 1 0
1 0 0 1 1
1 0 1 1 0
1 0 1 1 1
1 1 0 1 0
1 1 0 1 1
1 1 1 0 0
1 1 1 0 1
1 1 0 0 0
1 0 0 0 1
0 1 1 0 1
0 0 1 1 1
1 1 1 11
Used as inter-stream fill code
Start-of-Stream Delimiter (SSD),
part 1 of 2
Start-of-Stream Delimiter (SSD),
part 2 of 2
End-of-Stream Delimiter (ESD),
part 1 of 2
End-of-Stream Delimiter (ESD),
part 2 of 2
Interpretation
5.7 100 Mbps Operation
Data C
Data D
Data A
Data B
Data E
Data F
Data 0
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7
Data 8
Data 9
Table
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