Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com
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XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
OCTOBER 2003
REV. 1.2.1
GENERAL DESCRIPTION
The XRT72L50, single Channel DS3/E3 Framer IC is
designed to accept user data from the Terminal
Equipment and insert this data into the payload bit-
fields within an outbound DS3/E3 Data Stream. Fur-
ther, the Framer IC is also designed to receive an in-
bound DS3/E3 Data Stream from the Remote Termi-
nal Equipment and extract out the user data.
The XRT72L50 DS3/E3 Framer device is designed to
support full-duplex data flow between Terminal Equip-
ment and an LIU (Line Interface Unit) IC. The Framer
Device will transmit, receive and process data in the
DS3-C-bit Parity, DS3-M13, E3-ITU-T G.751 and E3-
ITU-T G.832 Framing Formats.
The XRT72L50 DS3/E3 Framer IC consists of a
Transmit section, Receiver section, Performance
Monitor Section and a Microprocessor interface.
The Transmit Section includes a Transmit Payload
Data Input Interface, a Transmit Overhead data Input
Interface Section, a Transmit HDLC Controller, a
Transmit DS3/E3 Framer block and a Transmit LIU In-
terface Block which permits the Terminal Equipment
to transmit data to a remote terminal.
The Receive Section consists of a Receive LIU Inter-
face, a Receive DS3/E3 Framer, a Receive HDLC
Controller, a Receive Payload Data Output Interface,
and a Receive Overhead Data Interface which allows
the local terminal equipment to receive data from re-
mote terminal equipment.
The Microprocessor Interface is used to configure the
Framer IC in different operating modes and monitor
the performance of the Framer.
The Performance Monitor Sections consist of a large
number of Reset-upon-Read and Read-Only regis-
ters that contain cumulative and one-second statistics
that reflect the performance/health of the Framer IC/
system.
FEATURES
Transmits, Receives and Processes data in the
DS3-C-bit Parity, DS3-M13, E3-ITU-T G.751 and
E3-ITU-T G.832 Framing Formats.
1 Channel HDLC Controller - Tx and Rx
Interfaces to all Popular Microprocessors
Integrated Framer Performance Monitor
Available in a 100 Pin PQFP package
3.3V Power Supply with 5V Tolerant I/O
Operating Temperature -40°C to +85°C
APPLICATIONS
Network Interface Units
CSU/DSU Equipment.
PCM Test Equipment
Fiber Optic Terminals
DS3/E3 Frame Relay Equipment
FIGURE 1. BLOCK DIAGRAM OF THE XRT72L50
T3/E3 Transm it
Fram er
T3 FEAC & Data
Link C ontroller
T3/E3 R eceive
Fram er
Perform ance
Monitor
Interrupt
Controller
TxO HInd
TxN ibFram e
TxFram e
TxN ibC lk
TxLnC lk
TxFram eR ef
TxN ib
TxSer
T3/E3
transm it
Input
RxC lk
RxO Hind
RxFram e
RxN ib
RxSer
RxO utClk
T3/E3
Receive
O utput
A[8:0]
D[7:0]
ALE_AS
WR _R /W
CS
RD Y_DTCK
Reset
Int
MO TO
RD _D S
P
Interface
TxLineClk
TxPO S
TxN EG
RxLineClk
RxPO S
RxN EG
ExtLO S
LIU
Interface/
Controller
TestM ode
NibIntf
TxO HEnable
TxO HC lk
TxO HFram e
TxAISEn
TxO H
TxO HIns
T3/E3
Transm it
O verhead
Interface
RxO HEnable
RxO HC lk
RxO H
RxR ed
RxO HFram e
RxOOF
T3/E3
Receive
O verhead
Interface
HD LC
controller
HD LC
controller
TRST