dp83251 National Semiconductor Corporation, dp83251 Datasheet - Page 90

• Manufacturer Part Number: dp83251
• Description: Player Device Fddi Physical Layer Controller
• Manufacturer: National Semiconductor Corporation

8 0 Detailed Descriptions
F IDLE
W
nn
N
X
V
I
ALSZILSZ
H
R
S
T
JK
I
V
E TPARITY
E ALSZILSZ Not in Active Line State nor in Idle Line
TABLE 8-1 Abreviations used in
the Repeat Filter State Diagram
Force Idle True when not in Active
Transmit Mode
Represents the symbols R or S or T
Parity error
Data symbols (for C
Interface)
Data portion of a control and data symbol
mixture
Any symbol (i e don’t care)
Violation symbols or symbols inserted by
the Receiver Block
Idle symbols or symbols inserted by the
Receiver Block
Active Line State or Idle Line State (i e
PHY Invalid)
State (i e PHY Valid)
Halt symbol
Reset symbol
Set symbol
Frame ending delimiter
Frame start delimiter
Idle symbol (Preamble)
Code violations
e
0 in the PHY-MAC
(Continued)
90
The Repeat Filter complies with the FDDI standard by ob-
serving the following
1 In Repeat State violations cause transitions to the Halt
2 When Ix is encountered the Repeat Filter goes to the Idle
3 The Repeat Filter goes to the Repeat State following a JK
The END State which is not part of the FDDI standard
allows an R or S prior to a T within a frame to be recognized
as a violation It also allows NT to end a frame as opposed
to being treated as a violation
State and two Halt symbol pairs are transmitted (unless
JK or Ix occurs) followed by transition to the Idle State
State during which Idle symbol pairs are transmitted until
a JK is encountered
from any state