
PM7346 S/UNI-QJET
DATASHEET
PMC-960835
ISSUE 6
SATURN QUAD USER NETWORK INTERFACE FOR J2, E3, T3
PMC-SIERRA, INC. PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA INC., AND ITS CUSTOMERS’ INTERNAL USE
307
Overhead Field
Transmit Operation
result calculated for the
previous frame.
The first four bit positions
provide a PLCP far end block
error function and indicates
the number of B1 errors
detected at the near end.
The FEBE field has nine legal
values (0000b-1000b)
indicating between zero and
eight B1 errors.
The fifth bit position is used
to transmit PLCP yellow
alarm. The last three bit
positions provide the link
status signal used in IEEE-
802.6 DQDB
implementations. Yellow
alarm and link status signal
insertion is controlled by the
internal registers or by TPOH
pin.
These octets carry the DQDB
layer management
information. Internal register
controls the nominal value
inserted in these octets.
These octets are unused in
ATM Forum T3 UNI 3.0
specification.
The coding of this octet
depends on the PLCP frame
format. For DS1 and E3
PLCP formats, this octet is
programmed with all zeros.
For the DS3 PLCP format,
this octet indicates the
number of stuff nibbles (13 or
14) at the end of each PLCP
frame. The C1 value is varied
in a three frame cycle where
the first frame always
Receive Operation
accumulated in a counter in the
CPPM block.
The G1 byte provides the PLCP
FEBE function and is accumulated
in an a counter in the CPPM block.
PLCP yellow alarm is detected or
removed when the yellow bit is set
to logic one or zero for ten
consecutive frames. The yellow
alarm state and the link status
signal state are contained in the
SPLR Status register.
G1:
Path Status
M1, M2:
Control
Information
These octets are ignored and are
extracted on the RPOH pin.
C1:
Cycle/Stuff
Counter
Interprets the trailer length
according to the selected PLCP
frame format and the received C1
code.