dp83261 National Semiconductor Corporation, dp83261 Datasheet - Page 73

• Manufacturer Part Number: dp83261
• Description: Bmac Device Fddi Media Access Controller
• Manufacturer: National Semiconductor Corporation

7 0 Signal Descriptions
7 2 1 PHY Interface Codes
The DP83251 155 PLAYER device converts the Standard 4B 5B FDDI symbol code to the internal code used at the PHY
Interface The PH DATA Indication table shows how the Ring Engine interprets the codes generated by the PLAYER device
and the PH DATA Request table shows the codes generated by the Ring Engine
The internal code is actually an 8B 9B code with parity where one bit is used to determine whether the symbol pair contains two
data symbols or at least one control symbol
PH DATA Indication
The Ring Engine interprets the byte stream the PLAYER device as defined in Table 7-1
where
The PLAYER device aligns the received JK to a byte boundary Thus no provision is made in the internal code or by the Ring
Engine for off boundary JKs
The Idle and PH Invalid encodings overlap Idle symbols received while the PLAYER device is in Active Line State (ALS) or Idle
Line State (ILS) are not considered PH INVALID Idle symbols received while the PLAYER device is in states other than ALS or
ILS are treated as PH Invalid
PIP
PIC
PID(7 – 0) PHY Indicate Data(7 – 0)
P
x –
PHY Indicate Parity bit ODD parity
PHY Indicate Control bit
0
1
represents ODD Parity ( E P is Bad Parity)
represents a don’t care and is not decoded
represents a 1 or 0 but not both
e
e
0
1
254
255
JK
PI
PI
II
nI
RR
RS
RT
SS
SR
ST
SX
TX
TR
TS
TT
nT
Parity Error
Otherwise
l
l
Value
data byte
control mixed byte
PIP
E P
1
0
0
1
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
(Continued)
TABLE 7-1 Internal PHY Indicate Coding
PIC
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
1
PID(7 – 4)
0000
0000
1111
1111
1101
0000
0110
0110
0110
0111
0111
0111
0111
0101
0101
0101
0101
0000
x011
x011
10xx
73
Else
PID(3 – 0)
0000
0001
1110
1111
0110
0111
0101
0111
0110
0101
0110
0111
0101
0101
x1xx
xx1x
10xx
xxxx
xxxx
xxxx
xxxx
Data Symbol Pair
Data Symbol Pair
Data Symbol Pair
Data Symbol Pair
Start Delimiter
PH Invalid
PH Invalid
Idle Symbols
Data Idle Symbol
Frame Status
Frame Status
Frame Status
Frame Status
Frame Status
Frame Status
Frame Status
Ending Delimiter
Ending Delimiter
Ending Delimiter
Ending Delimiter
Mixed Symbol Pair
Code Violation
Code Violation
Type