PM7375-SC datasheet(70/430 Pages) PMC

70 / 430 page

PM7375 LASAR-155

DATA SHEET

PMC-931127

ISSUE 6

LOCAL ATM SAR & PHYSICAL LAYER

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

For each cell, the TALP block generates the GFC, VPI, VCI, PTI and CLP cell

header fields. The GFC, VPI and VCI fields are inserted from the values

programmed when the VC was initially provisioned. The PTI and CLP fields are

inserted from the default values from when the VC was initially provisioned or as

specified by the PCI Host on a per packet basis.

CRC-10 field generation and inclusion is provided to support F4 and F5 OAM cell

generation. For F4 and F5 OAM cells, the CRC-10 is generated using the

polynomial, x10+x9+x5+x4+1. The OAM cell flow is expected to be either from the

PCI Host or through the Multipurpose Port. When the flow is through the

Multipurpose Port, the ATM header bytes GFC, VPI, VCI, PTI and CLP must be

pre-pended by the external cell source.

The Multipurpose Port is provided to allow either insertion of CBR cells and/or OAM

cells into the cell stream. When the port indicates that a cell is ready to be

transmitted, the TALP block either inserts the cell into the aggregate cell stream at

the earliest opportunity or waits until no cells are being sourced from the PCI Host

before inserting the cell into the aggregate cell stream. The selection of the insertion

mode is made using the CINPORT_PR bit in the TALP Control register.

No per VC traffic shaping is applied to this stream. Only traffic shaping of the

aggregate cell stream sourced from the Multipurpose Port is provided.

The TALP block enforces an APCR on the aggregate cell stream using a peak cell

rate counter. The APCR can be selectable from 32 Kbps to the full rate of 149

Mbit/s for STS-3c (STM-1).

9.9

Transmit ATM Cell Processor

The Transmit ATM Cell Processor (TACP) provides rate adaptation via

idle/unassigned cell insertion, provides HEC generation and insertion, provides GFC

insertion and performs ATM cell scrambling.

Idle/Unassigned Cell are transmitted in the absence of assigned cells. Registers

are provided to program the GFC, PTI, and CLP fields of the Idle/Unassigned cell

header and the cell payload. The HEC is automatically calculated and inserted.

The HEC calculation over the first four header octets is performed using the

polynomial, x8+x2+x+1. The coset polynomial, x6+x4+x2+1 is optionally added

(modulo 2) to the residue.

Scrambling is performed using the self synchronous scrambler, x43+1. Scrambling

is performed only over cell payloads; cell headers are not scrambled.

PM7375-SC Datasheet(PDF) 70 Page - PMC-Sierra, Inc