![](http://datasheet.mmic.net.cn/260000/PM7390-BI_datasheet_15944927/PM7390-BI_42.png)
Multi-Service Access Device For Channelized Interfaces
Telecom Standard Product Data Sheet
Production
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990823, Issue 4
42
8
Description
The PM7390 S/UNI-MACH48 is a monolithic integrated circuit that implements ATM mapping
and Packet over SONET/SDH mapping functions for a channelized STS-48/STM-16 stream. The
2.488Gb/s stream can consist of a single STS-48c/STM-16c or a combination of STS-12c/STM-
4c, STS-3c/STM-1, STS-1/STM-0, and DS3 channels.
8.1
Receive Direction
The S/UNI-MACH48 can be configured to use either a 77.76 MHz TTL compatible parallel
TelecomBus or a set of 777.6 Mbps LVDS compatible serial TelecomBus line-side interface to
transmit and receive SONET/SDH data streams.
The incoming TTL compatible parallel TelecomBus can carry an STS-48/STM-16 stream or four
STS-12/STM-4 streams that share a common clock and a common transport frame alignment.
The parallel TelecomBus interface is compatible with SONET/SDH framers such as the
SPECTRA-2488, SPECTRA-622, and SPECTRA-4x155.
Each incoming LVDS compatible serial TelecomBus link carries a constituent STS-12/STM-4 of
an STS-48/STM-16 stream. Bytes on the links are carried on an extended 8B/10B character set
which encodes TelecomBus data and control signals.
The S/UNI-MACH48 optionally performs AU3/AU4 pointer processing to account for positive
and negative pointer justifications on the incoming data streams.
A pseudo-random bit sequence (PRBS) processor is provided to monitor the decoded payload for
the X
23
+ X
18
+ 1 pattern. The PRBS processor is configurable to handle all legal mixes of
STS-1/AU3, STS-3c/AU4, STS-12c/AU4-4c and STS-48c/AU4-16c in the serial TelecomBus or
parallel TelecomBus interface. When using the serial TelecomBus, data to the S/UNI-MACH48
core may be sourced from arbitrary time-slots of any of the two sets of LVDS links.
A DS-3 demapper permits extraction of the DS-3 frame from an STS-1 SPE as per Bellcore,
ANSI, and ITU specifications. A full featured DS-3 framer provides framing and error
accumulation in accordance with ANSI T1.107, and T1.107a. The DS3 framer frames to a DS3
signal with a maximum average reframe time of 1.5 ms and detects framing bit errors, parity
errors, path parity errors, AIS, far end receive failure, and idle code. The DS3 overhead bits are
extracted and presented on multiplexed serial outputs. When in C-bit parity mode, the Path
Maintenance Data Link and the Far End Alarm and Control (FEAC) channels are extracted.
HDLC receivers are provided for Path Maintenance Data Link support. In addition, valid bit-
oriented codes in the FEAC channels are detected and are available through the microprocessor
port.
PLCP sublayer DS3 processing is also supported. In the PLCP receive direction, framing is
provided. BIP-8 error events, frame octet error events and far end block error events are
accumulated.
A single DS3 PRBS detectors permits DS3 line error diagnostics on the selected DS3 channel.