XRT72L54 Datasheet, PDF (29/484 Pages) Exar Corporation – FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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PRELIMINARY
PIN DESCRIPTION
PIN #
PIN NAME
C9
DMO[0]
C10
RxOHFrame[1]/
RxHDLCDat4[1]
C11 TxOHEnable[1]/
TxHDLCDat7[1]
C12
RxOH[0]/
RxHDLCDat6[0]
C13
TxOHFrame[0]/
TxHDLCClk[0]
C14
TxOHIns[0]/
TxHDLCDat4[0]
XRT72L54
FOUR CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
TYPE
I
O
O
I
O
O
I
DESCRIPTION
"Drive Monitor Output" Input (from the XR-T7300 DS3/E3 Line
Interface Unit IC):
This input pin is intended to be tied to the DMO output pin of the
XRT7300 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 XRT7300 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 XRT7300 device.
If this customer is not using the XR-T7300 DS3/E3 Line Interface Unit
IC, then he/she can use this input pin for a variety of other purposes.
See Description for Pin A13
See Description for Pin B14
Receive Overhead Output Port:
All overhead bits, which are received via the "Receive Section" of the
Framer IC; will be output via this output pin, upon the rising edge of
RxOHClk.
Receive HDLC Data Output - 6:
This pin contains bit 6 RxHDLC data when the HDLC controller is on.
Transmit Overhead Framing Pulse:
This output pin pulses "high" when the Transmit Overhead Data Input
Interface block is expecting the first Overhead bit, within a DS3 or E3
frame to be applied to the TxOH input pin.
This pin is "high" for one clock period of TxOHClk.
Transmit HDLC Output Clock:
When the HDLC controller is on, TxHDLCDat is updated by the 72L54
by this clock signal.
Transmit Overhead Data Insert Input:
Asserting this input signal (e.g., setting it "high") enables the Transmit
Overhead Data Input Interface to accept "overhead" data from the Ter-
minal Equipment. In other words, while this input pin is "high", the Trans-
mit Overhead Data Input Interface will sample the data at the "TxOH"
input pin, on the falling edge of the "TxOHClk" output signal.
Conversely, setting this pin "low" configures the "Transmit Overhead
Data Input Interface" to NOT sample (e.g., ignore) the data at the
"TxOH" input pin, on the falling edge of the "TxOHClk" output signal.
NOTE: If the Terminal Equipment attempts to insert an overhead bit that
cannot be accepted by the "Transmit Overhead Data Input Interface"
(e.g., if the Terminal Equipment asserts the "TxOHIns" signal, at a time
when one of these "non-insertable" overhead bits are being processed);
that particular insertion effort will be ignored.
Transmit HDLC Data Input - 4:
This pin accepts bit 4 TxHDLC data when the HDLC controller is turned
on.
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