PM5347 datasheet(61/302 Pages) PMC

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PM5347 S/UNI-PLUS

DATA SHEET

PMC-941033

ISSUE 6

SATURN USER NETWORK INTERFACE PLUS

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

While in-frame, the framing bytes (A1, A2) in each frame are compared against

the expected pattern. Out-of-frame is declared when four consecutive frames

containing one or more framing pattern errors have been received.

While out-of-frame, the SIPO block monitors the receive stream for an

occurrence of the framing pattern. When a framing pattern has been recognized,

the Framer block verifies that an error free framing pattern is present in the next

frame before declaring in-frame.

Descramble

The Descramble Block utilizes a frame synchronous descrambler to process the

receive stream. The generating polynomial is x7 + x6 + 1 and the sequence

length is 127. Details of the descrambling operation are provided in the

references. Note that the framing bytes (A1 and A2) and the trace/growth bytes

(J0/Z0) are not descrambled. A register bit is provided to disable the

descrambling operation.

Error Monitor

The Error Monitor Block calculates the received section BIP-8 error detection

code (B1) based on the scrambled data of the complete STS-3c/1 (STM-1)

frame. The section BIP-8 code is based on a bit interleaved parity calculation

using even parity. Details are provided in the references. The calculated BIP-8

code is compared with the BIP-8 code extracted from the B1 byte of the following

frame. Differences indicate that a section level bit error has occurred. Up to

64000 (8 x 8000) bit errors can be detected per second. The Error Monitor Block

accumulates these section level bit errors in a 16-bit saturating counter that can

be read via the microprocessor interface. Circuitry is provided to latch this

counter so that its value can be read while simultaneously resetting the internal

counter to 0 or 1, if appropriate, so that a new period of accumulation can begin

without loss of any events. It is intended that this counter be polled at least once

per second so as not to miss bit error events.

Loss of Signal

The Loss of Signal Block monitors the scrambled data of the receive stream for

the absence of 1's. When 20 ± 3 µs of all zeros patterns is detected, a loss of

signal (LOS) is declared. Loss of signal is cleared when two valid framing words

are detected and during the intervening time, no loss of signal condition is

detected. LOS is updated on the falling edge of GROCLK.

PM5347 Datasheet(PDF) 61 Page - PMC-Sierra, Inc