XRT72L53 Datasheet, PDF (11/467 Pages) Exar Corporation – THREE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L53
THREE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.7
áç
PRELIMINARY
PIN DESCRIPTION CONNECTED PINS
PIN #
C6
PIN NAME
TAOS[0]
C7
LLOOP[0]
C8
RLOL[1]
C9
DMO[0]
C10
RxOHFrame[1]/
RxHDLCDat4[1]
C11 TxOHEnable[1]/
TxHDLCDat7[1]
TYPE
O
O
I
I
O
O
I
DESCRIPTION
Transmit All Ones Signal (TAOS) Command Input - Channel 0 (for
the DS3/E3 LIU IC):
This output pin is intended to be connected to the TAOS input pin of the
DS3/E3 Line Interface Unit IC. The user can control the state of this out-
put pin by writing a '0' or '1' to Bit 4 (TAOS) of the Line Interface Drive
Register (Address = 0x80). If the user commands this signal to toggle
"High" then it will force the Line Interface Unit IC to transmit an "All
Ones" pattern onto the line. Conversely, if the user commands this out-
put signal to toggle "Low" then the DS3/E3 Line Interface Unit IC will
proceed to transmit data based upon the pattern that it receives via the
TxPOS[0] and TxNEG[0] output pins.
Writing a "1" to Bit 4 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 this output pin to toggle "Low".
If the customer is not using an Exar “XRT73L0X Family of DS3/E3 LIU
ICs then this output pin can be used for a variety of other purposes.
Local Loopback Output Pin - Channel 0 (to be connected to the
DS3/E3 Line Interface Unit IC):
This output pin is intended to be connected to the LLOOP input pin of
the DS3/E3 LIU IC. The user can command this signal to toggle "High"
and, in turn, force the LIU into the Local Loopback mode.
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: This output pin can be used as a General Purpose Output.
Receive Loss of Lock Indicator input - Channel 1 (from the DS3/E3
LIU IC):
See Description for Pin B8
Drive Monitor Output Input pin - Channel 0 (from the DS3/E3 Line
Interface Unit IC):
This input pin is intended to be tied to the DMO output pin of the DS3/
E3 Line Interface Unit IC. The user can determine the state of this input
pin by reading Bit 2 (DMO) within the Line Interface Scan Register
(Address = 0x81). If this input signal is "High", then it means that the
drive monitor circuitry (within the DS3/E3 Line Interface Unit IC) has not
detected any bipolar signals at the MTIP and MRING inputs within the
last 128 (32 bit-periods. If this input signal is "Low", then it means that
bipolar signals are being detected at the MTIP and MRING input pins of
the DS3/E3 LIU device.
NOTE: This input pin can be used as a General Purpose Input pin.
Receive Overhead Frame Boundary Indicator/Receive HDLC Con-
troller Data Output - Bit 4; Channel 1:
See Description for Pin A13
Transmit Overhead Data Input Enable/Transmit HDLC Controller
Data Output - Bit 7; Channel 1:
See Description for Pin B14
11