DP83256 datasheet(27/144 Pages) NSC

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30 Functional Description (Continued)

37 PHY-MAC INTERFACE

NATIONAL BYTE-WIDE CODE

The PLAYERa device outputs the National byte-wide code

from its PHY Port Indicate Output to the MAC device Each

National byte-wide code may contain data or control codes

or the line state information of the connection Table 3-7

lists all the possible outputs

During Active Line State all data and control symbols are

being repeated to the PHY Port Indicate Output with the

exception of data in data-control mixture bytes That data

symbol is replaced by zero If only one symbol in a byte is a

control symbol the data symbol will be replaced by 0000

and the whole byte will be presented as control code Note

that the Line State Detector recognizes the incoming data

to be in the Active Line State upon reception of the Starting

Delimiter (JK symbol pair)

During Idle Line State any non Idle symbols will be reflected

as the code I uILS If both symbols received during Idle Line

State are Idle symbols then the Symbol Decoder generates

I kILS as its output Note the coded KnownUnknown Bit

(b3) and the Last Known Line State (b2 – 0) The Receive

State is 4 bits long and it represents either the PHY Invalid

(0011) or the Idle Line State (1011) condition The Known

Unknown Bit shows if the symbols received match the line

state information in the last 3 bits

During any line state other than Idle Line State or Active

Line State the Symbol Decoder generates the code V kLS

if the incoming symbols match the current line state The

symbol decoder generates V uLS if the incoming symbols

do not match the current line state

TABLE 3-7 National Byte Wide Code

Current Line State

Symbol 1

Symbol 2

National Code

Control Bit

Data

Control Bit

Data

Control Bit

Data

ALS

n-n

ALS

N-C

ALS

C-N

ALS

C-C

ILS

1I -k-LS

ILS

Not I

I -u-LS

ILS

Not I

I -u-LS

ILS

Not I

I -u-LS

Stuff Byte during ILS

I -k-ILS

Not ALS and Not ILS

V -k-LS

Not ALS and Not ILS

Not M

V -u-LS

Not ALS and Not ILS

Not M

V -u-LS

Not ALS and Not ILS

Not M

V -u-LS

Stuff Byte during Not ALS

V -k-LS V -u-LS

or L -u-ILS

EB OverflowUnderflow

0011 1011

SMT

PI Connection (LSU)

0011 1010

Scrub Symbol Pair

1011 1000

Where

Any data symbol in 0 1 2

Any control symbol in V R S T I H

0000 e Code for data symbol in a data control mixture byte

Idle Symbol

M e Any symbol that matches the current line state

1011 e First symbols of the byte in Idle Line State

0011 e PHY Invalid

LS e Line State

ALS e 000

ILS

001

NSD e 010

MLS e 100

HLS e 101

QLS e 110

NLS e 111

Indicates symbol received does not match current line state

Indicate symbol received matches current line state

Don’t care

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