AM79C973BKD AMD (ADVANCED MICRO DEVICES), AM79C973BKD Datasheet - Page 82

• Manufacturer Part Number: AM79C973BKD
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of AM79C973BKD

• Lead Free Status / RoHS Status: Compliant

Encoder
The encoder converts the 4-bit nibble from the MII into
five-bit code-groups, using a 4B/5B block coding
scheme. The encoder operates on the 4-bit data nibble
independent of the code-group boundar y. The
100BASE-X physical protocol data unit is called a
stream. The encoding method used provides the fol-
lowing:
82
TXD[3:0]
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
Undefined
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 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
0 1 10
Name
C
D
R
H
A
B
E
F
K
T
V
V
V
V
V
V
V
V
V
V
0
1
2
3
4
5
6
7
8
9
J
I
Table 8. Encoder Code-Group Mapping
P R E L I M I N A R Y
PCS Code-Group
Am79C973/Am79C975
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 1 1 1
1 1 0 0 0
1 0 0 0 1
0 1 1 0 1
0 0 1 1 1
0 0 1 0 0
0 0 0 0 0
0 0 0 0 1
0 0 0 1 0
0 0 0 1 1
0 0 1 0 1
0 0 1 1 0
0 1 0 0 0
0 1 1 0 0
1 0 0 0 0
1 1 0 0 1
The code-group mapping is defined in Table 8.
Adequate codes (32) to provide for all data code-
groups (16) plus necessary control code-groups.
Appropriate coding efficiency (4 data bits per 5
code-bits; 80%) to implement a 100-Mbps physical
layer interface on a 125-Mbps physical channel.
Sufficient transition density to facilitate clock recov-
ery (when not scrambled).
Interpretation
End-of-Stream Delimiter, Part 1 of 2; always used in
End-of-Stream Delimiter, Part 2 of 2; always used in
Start-of-Stream Delimiter, Part 1 of 2; always used
Start-of-Stream Delimiter, Part 2 of 2; always used
Transmit Error; used to force signaling errors
IDLE; used as inter-Stream fill code
in pairs with K
in pairs with J
Invalid Code
Invalid Code
Invalid Code
Invalid Code
Invalid Code
Invalid Code
Invalid Code
Invalid Code
Invalid Code
Invalid Code
pairs with R
pairs with T
Data A
Data B
Data C
Data D
Data E
Data 0
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6
Data 7
Data 8
Data 9
Data F