Datasheet

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DP83865
4.0 Functional Description (Continued)
dB. The DP83865 uses the PHYADDR[4:0] value to set a
unique seed value for the scramblers. The resulting energy
generated by each channel is out of phase with respect to
each channel, thus reducing the overall electro-magnetic
radiation.
4.7.8 NRZ to NRZI Encoder
After the transmit data stream has been serialized and
scrambled, the data is NRZI encoded to comply with the
TP-PMD standard for 100BASE-TX transmission over Cat-
egory-5 unshielded twisted pair cable. There is no ability to
bypass this block within the DP83865.
Table 52. 4B5B Code-Group Encoding/Decoding
Name PCS
5B
Code-
group
MII 4B Nibble Code
DATA CODES
0 11110 0000
1 01001 0001
2 10100 0010
3 10101 0011
4 01010 0100
5 01011 0101
6 01110 0110
7 01111 0111
8 10010 1000
9 10011 1001
A 10110 1010
B 10111 1011
C 11010 1100
D 11011 1101
E 11100 1110
F 11101 1111
IDLE AND CONTROL CODES
H 00100 HALT code-group - Error code
I 11111 Inter-Packet IDLE - 0000 (Note 1)
J 11000 First Start of Packet - 0101 (Note 1)
K 10001 Second Start of Packet - 0101 (Note 1)
T 01101 First End of Packet - 0000 (Note 1)
R 00111 Second End of Packet - 0000 (Note 1)
INVALID CODES
V 00000 0110 or 0101 (Note 2)
V 00001 0110 or 0101 (Note 2)
V 00010 0110 or 0101 (Note 2)
V 00011 0110 or 0101 (Note 2)
V 00101 0110 or 0101 (Note 2)
V 00110 0110 or 0101 (Note 2)
V 01000 0110 or 0101 (Note 2)
V 01100 0110 or 0101 (Note 2)
V 10000 0110 or 0101 (Note 2)
V 11001 0110 or 0101 (Note 2)
Note 1: Control code-groups I, J, K, T and R in data fields will be
mapped as invalid codes, together with RX_ER asserted.
Note 2: Normally, invalid codes (V) are mapped to 6h on RXD[3:0] with
RX_ER asserted.