XRT72L58 Datasheet, PDF (32/486 Pages) Exar Corporation – EIGHT CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L58
EIGHT CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
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PRELIMINARY
PIN DESCRIPTION FOR THE XRT72L58
PIN #
D22
D23
D24
D25
D26
E1
PIN NAME
RxLOS[2]
RxNib2[2]/
RxHDLCDat2[2]
RxOHClk[2]/
RxHDLCClk[2]
RxOHEnable[2]/
RxHDLCDat5[2]
TxNibFrame[2]/
ValFCS[2]
TxPOS[7]
E2
ExtLOS[7]
E3
TMS
E4
TDI
E23
RxOH[2]/
RxHDLCDat6[2]
E24
TxNibClk[2]/
SndFCS[2]
TYPE
O
O
See Description of Pin A8
See Description of Pin A10
DESCRIPTION
O
See Description of Pin A7
O
See Description of Pin A17
O
See Description of Pin A12
O
Transmit Positive 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 pin functions as the "Single-Rail" output signal for the "outbound"
DS3 or E3 data stream. The signal, at this output pin, will be updated on the
"user-selected" edge of the TxLineClk signal.
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. TxNEG is the other
output pin. This input is typically connected to the TPDATA input of the exter-
nal DS3 or E3 Line Interface Unit IC. When this output is asserted, it will com-
mand the LIU to generate a positive polarity pulse on the line
I
Receive LOS (Loss of Signal) Indicator Input (from XRT73xx LIU IC):
This input pin is intended to be connected to the RLOS (Receive Loss of Sig-
nal) output pin of the XRT73xx 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 XRT73xx is currently NOT
declaring an "LOS (Loss of Signal) condition. However, if this input pin is
"high", then it means that the XRT73xx is currently declaring an LOS (Loss of
Signal) condition.
For more information on the operation of the XR-T73xx DS3/E3 Line Receiver
IC, please consult the "XRT73xx DS3/STS-1/E3 Line Interface Unit IC" data
sheet.
Asserting the RLOS input pin will cause the XRT72L58 DS3/E3 Framer to
declare an "LOS (Loss of Signal) condition. Therefore, this input pin should
not be used as a general purpose input.
I
Test Mode Select: Boundary Scan Mode Select input
I
Test Data In: Boundary Scan Test data input
O
See Description of Pin B11
O
See Description of Pin A2
I
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