XRT72L58 Datasheet, PDF (33/486 Pages) Exar Corporation – EIGHT CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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PRELIMINARY
XRT72L58
EIGHT CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
PIN DESCRIPTION FOR THE XRT72L58
PIN #
E25
E26
F1
PIN NAME
TxOHInd[2]/
TxHDLCDat6[2]
TxOHClk[2]
TxNEG[7]
F2
RxOutClk[7]/
RxHDLCDat7[7]
F3
RxNEG[7]
F4
TDO
F23
TxFrame[2]
F24
TxOHEnable[2]/
TxHDLCDat7[2]
F25
TxAISEn[2]
F26
TxOH[2]/
TxHDLCDat5[2]
TYPE
O
I
O
O
O
I
O
O
O
I
I
I
See Description of Pin A6
DESCRIPTION
See Description of Pin A13
Transmit Negative Polarity Pulse:
The exact role of this output pin depends upon whether the Framer is operat-
ing in the Unipolar or Bipolar Mode.
Unipolar Mode:
This output signal pulses "high" for one bit period, at the end of each "out-
bound" DS3 or E3 frame. This output signal is at a logic "low" for all of the
remaining bit-periods of the "outbound" DS3 or E3 frames
Bipolar Mode:
This output pin functions as one of the two dual-rail output signals that com-
mands the sequence of pulses to be driven on the line. TxPOS is the other
output pin. This input is typically connected to the TNDATA input of the exter-
nal DS3/E3 Line Interface Unit IC. When this output is asserted, it will com-
mand the LIU to generate a negative polarity pulse on the line.
Receive Out Clock - Transmit Terminal Interface Clock for Loop-Timing:
This clock signal functions as the "Terminal Interface" clock source, if the
XRT72L58 Framer is operating in the "loop-timing" mode.
In this mode, the Transmitting Terminal Equipment is expected to input data to
the Framer, via the “TxSer” input pin, upon the rising edge of this clock signal.
The XRT72L58 will use the rising edge of this clock signal to sample the data
at the TxSer input.
This clock signal is a buffered version of the RxLineClk signal.
Receive HDLC Data Output - 7:
This pin contains bit 7 RxHDLC data when the HDLC controller is turned on.
Receive Negative Data Input:
The exact role of this input pin depends upon whether the Framer is operating
in the Unipolar or Bipolar Mode.
Unipolar Mode:
This input pin is inactive, and should be pulled ("low" or "high") when the
Framer is operating in the Unipolar Mode.
Bipolar Mode:
This input pin functions as one of the dual rail inputs for the incoming AMI/
HDB3 encoded DS3 or E3 data that has been received from an external Line
Interface Unit (LIU) IC. RxPOS functions as the other dual rail input for the
Framer. When this input pin is asserted, it means that the LIU has received a
"negative polarity" pulse from the line.
Test Data Out: Boundary Scan test data output
See Description of Pin B2
See Description of Pin A14
See Description of Pin A22
See Description of Pin A15
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