XRT72L54 Datasheet, PDF (24/484 Pages) Exar Corporation – FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L54
FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
áç
PRELIMINARY
PIN DESCRIPTION
PIN #
B2
PIN NAME
EncoDis[0]
B3
RxLOS[1]
B4
RxAIS[1]
B5
RxRed[0]
B6
Req[1]
B7
RLOOP[0]
TYPE
O
O
O
O
O
O
DESCRIPTION
Encoder (HDB3) Disable Output pin (intended to be connected to
the XRT7300 DS3/E3 Line Interface Unit IC):
This output pin is intended to be connected to the Encodis input pin of
the XRT7300 DS3/E3 Line Interface Unit IC. The user can control the
state of this output pin by writing a "0" or "1" to Bit 3 (Encodis) within the
Line Interface Driver Register (Address = 0x80). If the user commands
this signal to toggle "high" then it will disable the B3ZS/HDB3 encoder
circuitry within the XRT7300 IC. Conversely, if the user commands this
output signal to toggle "low", then the B3ZS/HDB3 Encoder circuitry,
within the XRT7300 IC will be enabled.
Writing a "1" to Bit 3 of the Line Interface Driver Register (Address =
0x80) will cause this output pin to toggle "high". Writing a "0" to this bit-
field will cause this output pin to toggle "low".
The user is advised to disable the B3ZS/HDB3 encoder (within the
XRT7300 IC) if the XRT72L54 Framer IC has been configured to oper-
ate in the B3ZS/HDB3 line code.
NOTE: If the customer is not using the XRT7300 DS3/E3 Line Interface
Unit IC, then he/she can use this output pin for a variety of other pur-
poses.
See Description for Pin C4
See Description for Pin C5
Receiver Red Alarm Indicator - Receive Framer:
The Framer asserts this output pin to denote that one of the following
events has been detected by the Receive Framer:
LOS - Loss of Signal Condition
OOF - Out of Frame Condition
AIS - Alarm Indication Signal Detection
See Description for Pin A5
Remote Loopback Output Pin (to the XRT7300 DS3/E3 Line Inter-
face Unit IC):
This output pin is intended to be connected to the RLOOP input pin of
the XRT7300 DS3/E3 Line Interface Unit IC. The user can command
this signal to toggle "high" and, in turn, force the XRT7300 DS3/E3 Line
Interface Unit IC into the "Remote Loopback" mode. Conversely, the
user can command this signal to toggle "low" and allow the XRT7300
device to operate in the normal mode. (For a detailed description of the
XR-T7300 DS3/E3 Line Interface Unit IC's operation during Remote
Loopback, please see the XR-T7300 DS3/STS-1/ E3 Line Interface Unit
IC's Data Sheet).
Writing a "1" to bit 1 of the "Line Interface Drive Register (Address =
0x80) will cause this output pin to toggle "high". Writing a "0" to this bit-
field will cause the RLOOP output to toggle "low".
NOTE: If the customer is not using the XRT7300 DS3/E3 Line Interface
Unit IC, then he/she can use this output pin for a variety of other pur-
poses.
5