XRT74L73 Datasheet, PDF (9/488 Pages) Exar Corporation – 3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER

PRELIMINARY
XRT74L73
3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
REV. P1.0.1
PIN DESCRIPTION
PIN#
NAME
TYPE
DESCRIPTION
General Purpose Input and Output Pins
C13
DMO_0
B13
DMO_1
A13
DMO_2
I
“Drive Monitor Output” Input (from the XRT73L03 LIU IC):
This input pin is intended to be tied to the DMO output pin of the XRT73L03 E3/
DS3/STS-1 LIU IC. The user can determine the state of this input pin by reading
Bit 2 (DMO) within the Line Interface Scan Register (Address = 0x73). If this
input signal is “High”, then it means that the drive monitor circuitry (within the
XRT73L03 LIU 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 XRT73L03 device.
NOTE: If the designer is not using the XRT73L03 E3/DS3/STS-1 LIU IC, then
this input pin can be used for other purposes.
R4
GPIO_0
T3
GPIO_1
T2
GPIO_2
T1
GPIO_3
I/O General Purpose Input/Output pins:
Each of these pin can be configured to function as either input or output pins. If a
given pin is configured to function as an Input pin, then the state of this input pin
can be monitored by reading Bit X within the "XXX" Register (Address Location =
0xXX, 0xXX).
If a given pin is configured to function as a Output pin, then the state of this out-
put pin can be controlled by writing the appropriate value into Bit X within the
"XXX" Register.
A5
LLOOP_0
D5
LLOOP_1
C4
LLOOP_2
O
Local Loop-back Output Pin (to the XRT73L03 E3/DS3/STS-1 LIU IC):
This output pin is intended to be connected to the LLOOP input pin of the
XRT73L03 LIU IC. This input pin, along with “RLOOP” permits the user to config-
ure the XRT73L03 LIU IC to operate in either of the following three (3) loop-back
modes.
• Analog Local Loop-Back Mode
• Digital Local Loop-Back Mode
• Remote Loop-Back Mode.
For a detailed description on how to configure the XRT73L03 to operate in each
of these loop-back modes, please see Section _.
Writing a “1” to bit 1 of the “Line Interface Drive Register” (Address = 0xXX,
0xXX) will cause this output pin to toggle “High”. Writing a “0” to this bit-field will
cause the RLOOP output to toggle “Low”.
NOTE: If the user is not using the XRT73L03 DS3/E3/STS-1 LIU IC, then this
output pin can be used for other purposes.
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