Functional Description

The Cypress Semiconductor CY7C955 is a Transceiver chip designed to carry ATM cells across SONET/SDH systems.

Features

? WAN and LAN ATM physical layer device

? Provides complete physical layer transport of ATM cells at:

— STS?3c/ STM?1 rate of 155.52 MHz

— STS?1 rate of 51.84 MHz

? Compliant with ATM Forum User Network Interface 3.1 specification

? UTOPIA ATM interface

? ATM cell processing including:

— HEC generation/verification

— Cell scrambling/descrambling

— Rate adaption/idle cell filtering

— Local Flow Control

— Cell alignment

? SONET frame processing including:

— Compliant with Bellcore GR?253, I.432, T1.105, and G.709 for Jitter Tolerance and Jitter Generation

— Frame generation/recovery

— SONET scrambling/descrambling

— Frequency justification/pointer processing

? Complete line interface including:

— Clock and data recovery

— Transmit timing derived from receiver or byte-rate source

— SONET compliant PLL

— 100K PECL compatible I/O

? Alarm indications including:

— Loss Of Signal

— Out Of Frame, Loss Of Frame

— Line Far End Receive Failure

— Line Alarm Indication Signal

— B1 Parity Error

— Loss Of Cell Alignment

— Loss Of Receive Data

? Controller interface for internal interrupt and configuration registers including:

— Error monitoring

— Status indication

— Device configuration

? 0.65μ Low Power CMOS

? 128-pin PQFP