XRT72L50 Datasheet, PDF (28/471 Pages) Exar Corporation – SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. 1.2.1
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PIN DESCRIPTION
PIN #
78
PIN NAME
ExtLOS
79
DMO
80
VDD
81
GND
82
RxNib3/
RxHDLCDat3
83
RxNib2/
RxHDLCDat2
TYPE
I
I
****
****
O
O
DESCRIPTION
Receive LOS (Loss of Signal) Indicator Input (from XRT73L00 LIU IC):
This input pin is intended to be connected to the RLOS (Receive Loss of Sig-
nal) output pin of the XRT73L00 Line Interface Unit IC. The user can monitor
the state of this pin by reading the state of Bit 0 (RLOS) within the Line Inter-
face Scan Register (Address = 0x81).
If this input pin is "Low", then it means that the XRT73L00 is currently NOT
declaring an LOS (Loss of Signal) condition. However, if this input pin is
"High", then it means that the XRT73L00 is currently declaring an LOS (Loss
of Signal) condition.
For more information on the operation of the XRT73L00 DS3/E3 Line
Receiver IC, please consult the XRT73L00 DS3/STS-1/E3 Line Interface Unit
IC data sheet.
Asserting the RLOS input pin will cause the XRT72L50 DS3/E3 Framer
device to declare an LOS (Loss of Signal) condition. Therefore, this input pin
should not be used as a general purpose input pin.
Drive Monitor Output Input (from the XRT73L00 DS3/E3 Line Interface
Unit IC):
This input pin is intended to be connected to the DMO output pin of the
XRT73L00 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 XRT73L00 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 sig-
nals are being detected at the MTIP and MRING input pins of the XRT73L00.
If this customer is not using the XRT73L00 DS3/E3 Line Interface Unit IC,
then he/she can use this input pin for a variety of other purposes.
Power Supply 3.3V + 5%
Ground
Receive Nibble Output - 3:
The Framer IC will output Received data (from the Remote Terminal) to the
local Terminal Equipment via this pin along with RxNib0, RxNib1 and RxNib2.
The data at this pin is updated on the rising edge of the RxClk output signal.
NOTE: This output pin is active only if the Nibble-Parallel Mode has been
selected.
Receive HDLC Data Output - 3:
This pin contains bit 3 RxHDLC data when the HDLC controller is on.
Receive Nibble Output - 2:
The Framer IC will output Received data (from the Remote Terminal) to the
local Terminal Equipment via this pin along with RxNib0, RxNib1 and RxNib2.
The data at this pin is updated on the rising edge of the RxClk output signal.
NOTE: This output pin is active only if the Nibble-Parallel Mode has been
selected.
Receive HDLC Data Output - 2:
This pin contains bit 2 RxHDLC data when the HDLC controller is on.
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