12
IDT82V2048 OCTAL T1/E1 SHORT HAUL LINE INTERFACE UNIT INDUSTRIAL TEMPERATURE RANGES
2 FUNCTIONAL DESCRIPTION
2.1 OVERVIEW
The IDT82V2048 is a fully integrated octal short-haul line interface
unit, which contains eight transmit and receive channels for use in either
T1 or E1 applications. The receiver performs clock and data recovery.
As an option, the raw sliced data (no retiming) can be output to the
system. Transmit equalization is implemented with low-impedance
output drivers that provide shaped waveforms to the transformer, guar-
anteeing template conformance. A selectable jitter attenuator may be
placed in the receive path or the transmit path. Moreover, multiple
testing functions, such as error detection, loopback and JTAG boundary
scan are also provided. The device is optimized for flexible software
control through a serial or parallel host mode interface. Hardware control
is also available. Figure-1 on page 1 shows one of the eight identical
channels operation.
2.2 T1/E1 MODE SELECTION
T1/E1 mode selection configures the device globally. In Hardware
Mode, the template selection pins TS[2:0], determine whether the opera-
tion mode is T1 or E1 (see Table-9 on page 19). In Software Mode, the
register TS determines whether the operation mode is T1 or E1.
2.2.1 SYSTEM INTERFACE
The system interface of each channel can be configured to operate
in different modes:
1. Single rail interface with clock recovery.
2. Dual rail interface with clock recovery.
3. Dual rail interface with data recovery (that is, with raw data
slicing only and without clock recovery).
Each signal pin on system side has multiple functions depending on
which operation mode the device is in.
The Dual Rail interface consists of TDPn
1
, TDNn, TCLKn, RDPn,
RDNn and RCLKn. Data transmitted from TDPn and TDNn appears on
TTIPn and TRINGn at the line interface; data received from the RTIPn
and RRINGn at the line interface are transferred to RDPn and RDNn
while the recovered clock extracting from the received data stream
outputs on RCLKn. In Dual Rail operation, the clock/data recovery mode
is selectable. Dual Rail interface with clock recovery shown in Figure-4
is a default configuration mode. Dual Rail interface with data recovery is
shown in Figure-5. Pin RDPn and RDNn, are raw RZ slice outputs and
internally connected to an EXOR which is fed to the RCLKn output for
external clock recovery applications.
In Single Rail mode, data transmitted from TDn appears on TTIPn
and TRINGn at the line interface. Data received from the RTIPn and
RRINGn at the line interface appears on RDn while the recovered clock
extracting from the received data stream outputs on RCLKn. When the
device is in single rail interface, the selectable AMI or B8ZS/HDB3 line
encoder/decoder is available and any code violation in the received data
will be indicated at the CVn pin. The Single Rail mode has 2 sub-modes:
Single Rail Mode 1 and Single Rail Mode 2. Single Rail Mode 1, whose
interface is composed of TDn, TCLKn, RDn, CVn and RCLKn, is real-
ized by pulling pin TDNn high for more than 16 consecutive TCLK
cycles. Single Rail Mode 2, whose interface is composed of TDn,
TCLKn, RDn, CVn, RCLKn and BPVIn, is realized by setting bit CRS in
register e-CRS
2
and bit SING in register e-SING. The difference
between them is that, in the latter mode bipolar violation can be inserted
via pin BPVIn if AMI line code is selected.
The configuration of the Hardware Mode System Interface is summa-
rized in Table-2. The configuration of the Host Mode System Interface is
summarized in Table-3.
Figure-4 Dual Rail Interface with Clock Recovery
1.
The footprint ‘n’ (n = 0 - 7) indicates one of the eight channels.
2.
The first letter ‘e-’ indicates expanded register.
Jitter
Attenuator
Jitter
Attenuator
B8ZS/
HDB3/AMI
Decoder
B8ZS/
HDB3/AMI
Encoder
Slicer
Peak
Detector
CLK&Data
Recovery
(DPLL)
Line
Driver
Waveform
Shaper
LOS
Detector
One of Eight Identical Channels
RTIPn
RRINGn
TTIPn
TRINGn
LOSn
RCLKn
RDPn
RDNn
TCLKn
TDNn
TDPn
Transmit
All Ones
Note: The grey blocks are bypassed and the dotted blocks are selectable.
