XRT72L54 Datasheet, PDF (31/484 Pages) Exar Corporation – FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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PRELIMINARY
PIN DESCRIPTION
PIN #
PIN NAME
D9
ExtLOS[0]
D10 RxOHEnable[1]/
RxHDLCDat5[1]
D11
VDD
D12
RxOHClk[0]/
RxHDLCClk[0]
D13
GND
D14
TxNib0[1]/
TxHDLCDat0[1]
D15
VDD
D16
TxNIBClk[1]/
SndFCS[1]
D17
GND
XRT72L54
FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
TYPE
I
O
****
O
****
I
****
O
I
****
DESCRIPTION
Receive LOS (Loss of Signal) Indicator Input (from XRT7300 LIU
IC):
This input pin is intended to be connected to the RLOS (Receive Loss
of Signal) output pin of the XRT7300 Line Interface Unit IC. The user
can monitor the state of this pin by reading the state of Bit 0 (RLOS)
within the Line Interface Scan Register (Address = 0x81).
If this input pin is "low", then it means that the XRT7300 device is cur-
rently NOT declaring an "LOS (Loss of Signal) condition. However, if
this input pin is "high", then it means that the XRT7300 device is cur-
rently declaring an LOS (Loss of Signal) condition.
For more information on the operation of the XR-T7300 DS3/E3 Line
Receiver IC, please consult the "XRT7300 DS3/STS-1/E3 Line Interface
Unit IC" data sheet.
Asserting the RLOS input pin will cause the XRT72L54 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.
See Description for Pin B13
Power Supply +3.3v ± 5%
Receive Overhead Output Clock Signal:
The XRT72L54 device will output the Overhead bits (within the incom-
ing DS3 or E3 frames), via the "RxOH" output pin, upon the falling edge
of this clock signal.
As a consequence, the "user's data link equipment" should use the ris-
ing edge of this clock signal to sample the data on both the "RxOH" and
"RxOHFrame" output pins.
NOTE: This clock signal is always active.
Receive HDLC Output Clock:
When the HDLC controller is on, RxHDLCDat is updated by the 72L54
on this clock signal.
Ground
See Description for Pin D18
Power Supply +3.3v ± 5%
See Description for Pin F18
Ground
12