PM7347 datasheet(265/341 Pages) PMC

265 / 341 page

S/UNI®-JET Data Sheet

Released

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use

265

Document ID: PMC-1990267, Issue 3

Overhead Field

Transmit Operation

Receive Operation

Growth:

nominally programmed with all

zeros. Access to these octets is

provided by the PLCP transmit

overhead access port.

the RPOH pin.

F1:

User Channel

This octet is unused and the value

inserted in this octet is controlled

by an internal register or by TPOH

pin.

This octet is ignored and is extracted on the

RPOH pin.

B1:

Bit Interleaved

Parity

This octet contains an 8-bit

interleaved parity (BIP) calculated

across the entire PLCP frame

(excluding the A1, A, Pn octets

and the trailer). The B1 value is

calculated based on even parity

and the value inserted in the

current frame is the BIP result

calculated for the previous frame.

The bit interleaved parity is calculated for the

current frame and stored. The B1 octet

contained in the subsequent frame is extracted

and compared against the calculated value.

Differences between the two values provide an

indication of the end-to-end bit error rate.

These differences are accumulated in a

counter in the CPPM block.

G1:

Path Status

The first four bit positions provide

a PLCP FEBE 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.

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.

M1, M2:

Control Information

These octets carry the DQDB layer

management information. Internal

inserted in these octets. These

octets are unused in ATM Forum

T3 UNI 3.0 specification.

These octets are ignored and are extracted on

the RPOH pin.

C1:

Cycle/Stuff Counter

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

contains 13 stuff nibbles, the

second frame always contains 14

nibbles, and the third frame

contains 13 or 14 nibbles. The

stuffing may be varied by a nibble

so that the PLCP frame rate can

be locked to an external 8 kHz

Interprets the trailer length according to the

selected PLCP frame format and the received

C1 code.

PM7347 Datasheet(PDF) 265 Page - PMC-Sierra, Inc

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