PM7345 datasheet(70/306 Pages) PMC

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PM7345 S/UNI-PDH

DATA SHEET

PMC-931011

ISSUE 6

SATURN USER-NETWORK INTERFACE

PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE

9.15 SPLT SMDS PLCP Layer Transmitter

The SMDS PLCP Layer Transmitter (SPLT ) Block integrates circuitry to support

DS1, DS3, E1, and G.751 E3 based PLCP frame insertion.

The SPLT automatically inserts the framing (A1, A2) and path overhead

identification (POHID) octets and provides registers or automatic generation of the

F1, B1, G1, M2, M1 and C1 octets.

Registers are provided for the path user channel octet (F1) and the path status octet

(G1). The bit interleaved parity octet (B1) and the FEBE subfield are automatically

inserted.

The DQDB management information octets, M1 and M2 are generated. The type 0

and type 1 patterns described in TA-TSY-000772 are automatically inserted. The

type 1 page counter may be reset using a register bit in the SPLT Configuration

UNI. For this application, the M1 and M2 octets must be set to all zeros.

The cycle/stuff counter octet, C1, may be controlled using the C13/CADD input, or a

fixed stuffing pattern may be inserted. A looped timing operating mode is provided

where the transmit PLCP timing is derived from the received timing. In this mode,

the C1 stuffing is generated based on the received stuffing pattern as determined by

the SPLR block. When DS1 or E1 PLCP format is enabled, the pattern 00H is

inserted.

When DS3 PLCP format is enabled, the C1 octet indicates the phase of the 375 µs

nibble stuffing opportunity cycle. During frame one of the three frame cycle, the

pattern FFH is inserted in the C1 octet, indicating a 13 nibble trailer length. During

frame two, the pattern 00H is inserted, indicating a 14 nibble trailer length. During

frame three, the pattern 66H or 99H is inserted, indicating a 13 or 14 nibble trailer

length respectively. The nibble trailer is set to the binary value 1100.

When configured for G.751 E3 PLCP frame format, the C1 octet is used to indicate

the number of octets stuffed in the trailer. The following table shows the C1 octet

pattern for each of the possible octet stuff lengths:

Stuff Length

C1(Hex)

PM7345 Datasheet(PDF) 70 Page - PMC-Sierra, Inc