XR72L52 Datasheet, PDF (31/480 Pages) Exar Corporation – TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
XRT72L52
REV. 1.0.1
PIN DESCRIPTION
PIN #
130
131
132
133
PIN NAME
TxNIBClk[0]/
SndFCS[0]
TxOHInd[0]/
TxHDLCDat6[0]
GND
TxSer[0]/
SndMsg[0]
TYPE
DESCRIPTION
O Transmit Nibble Clock Signal:
If the user opts to operate the XRT72L52 in the Nibble-Parallel mode, then the
XRT72L52 derives this clock signal from either the TxInClk or the RxLineClk sig-
nal, depending upon which signal is selected as the timing reference.
The user is advised to configure the Terminal Equipment to output the outbound
payload data to the XRT72L52 Framer onto the TxNib[3:0] input pins upon the
rising edge of this clock signal.
NOTES:
1. For DS3 applications, the XRT72L52 Framer outputs 1176 clock edges
to the Terminal Equipment for each outbound DS3 frame.
2. For E3, ITU-T G.832 applications, the XRT72L52 Framer outputs 1074
clock edges to the Terminal Equipment for each outbound E3 frame.
3. For E3, ITU-T G.751 applications, the XRT72L52 Framer outputs 384
clock edges fo the Terminal Equipment for each outbound E3 frame.
I Send Frame Check Sequence:
When the HDLC controller is turned on, this pin is driven "High" during the time
when FCS bytes are being sent after a valid HDLC message.
O Transmit Overhead Data Indicator:
This output pin pulses "High" one-bit period prior to the time that the Transmit
Section of the XRT72L52 is processing an Overhead bit. This output pin warns
the Terminal Equipment that during the very next bit-period, the XRT72L52 is
going to be processing an Overhead bit and ignoring any data that is applied to
the TxSer input pin.
NOTE: For DS3 applications, this output pin is only active if the XRT72L52 is
operating in the Serial Mode. This output pin is pulled "Low" if the device is oper-
ating in the Nibble-Parallel Mode.
I Transmit HDLC Data Input - 6:
This pin accepts bit 6 TxHDLC data when the HDLC controller is turned on.
**** Ground
I Transmit Serial Payload Data Input Pin:
The Terminal Equipment is expected to input data that is intended to be trans-
mitted to the remote terminal over an E3 or DS3 transport medium. The Framer
takes data applied to this pin and inserts it into an outbound E3 or DS3 frame.
If the XRT72L52 Framer IC has been configured to operate in the Local Time
Mode, then it samples the data on this pin upon the rising edge of TxInClk. If the
XRT72L52 Framer IC has been configured to operate in the Loop-Time Mode,
then it samples the data on this pin upon the rising edge of RxOutClk.
NOTE: This input pin is active only if the Serial Mode has been selected.
Send Message:
This input is to remain "High" during the entire duration of the HDLC packet
including FCS bytes to be transmitted when the HDLC controller is turned on.
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