
XRT7234
E3 UNI FOR ATM
x r
PRELIMINARY
REV. P1.0.0
48
Bit 6—Disable LOC
This “Read/Write” bit-field allows the user to enable or disable the “Loss of Clock signal” circuit. Writing a “1” to
this bit-field disables the “Loss of Clock” circuit. Writing a “0” to this bit-field enables the “Loss of Clock” circuit.
Bit 5—Int LOS Enable
This “Read/Write” bit-field allows the user to define the “Loss of Signal” (LOS) declaration criteria that the
Receive E3 Framer will use. At most, the Receive E3 Framer can declare an LOS condition if one of the follow-
ing two conditions are met.
1.
The RxPOS and RxNEG input pins are ‘stuck’ at “0” for 32 or more consecutive bit-periods.
2.
The XR-T7295 E3 Line Receive IC asserts the RLOS input pin of the UNI (please see Section 5.0).
Writing a “0” to this bit-field configures the Receive E3 Framer to declare an LOS condition only if the RLOS
input pin is asserted. In this configuration, the Receive E3 Framer will not declare an LOS condition if it detects
a string of 32 (or more) consecutive “0s”, in the incoming E3 data stream via the RxPOS and RxNEG pins.
Writing a “1” to this bit-field configures to the Receive E3 Framer to declare an LOS condition if either one of
the following two conditions occur:
The RxPOS and RxNEG input pins are stuck at “0” for 32 or more consecutive bit-periods.
If the RLOS input pin is asserted.
Bit 4 Reset By Reg (Reset by Register Setting)
This “Read/Write” bit-field allows the local
μ
P
/
μ
C to command a reset of the entire UNI IC. When the UNI is
reset, both the TxFIFO and the RxFIFO are flushed, all on-chip registers are reset to their default values, and
all configurations are automatically set to their default conditions.
Writing a “1” to this bit-field will reset the UNI IC. Writing a “0” to this bit-field imposes no change in the UNI IC.
Bit 3—“Cell Loopback” Mode
This “Read/Write” bit-field allows the user to configure the UNI to operate in the “Cell Loopback” mode. This is
a operating mode that is available via the UNI Test and Diagnostic Section. When the UNI is operating in this
mode, then the ATM Cells that are delineated and pass through the Receive Cell Processor will be routed directly
(internally) to the Tx FIFO (within the Transmit Utopia Interface block).
Writing a “1” to this bit-field enables the “Cell Loopback” Mode. Writing a “0” to this bit-field disables the Cell
Loopback Mode.
For more information on the Cell Loopback Mode of operation, please see Section 4.1.3.
Bit 2—“Line Loopback” Mode
This “Read/Write” bit-field allows the user to configure the UNI to operate in the “Line Loopback” mode. This is
a operating mode that is available via the UNI Test and Diagnostic Section. When the UNI is operating in this
mode, then the data stream from the TxPOS and TxNEG pins of the Transmit E3 Framer, are (internally) looped
back into the Receive RxPOS and RxNEG input pins of the Receive E3 Framer.
Writing a “1” to this bit-field enables the “Line Loopback” Mode. Writing a “0” to this bit-field disables the “Line
Loopback” Mode.
For more information on the Line Loopback Mode of operation, please see Section 4.1.1.
Sel(0)
R/O
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
1
1
0
0
0
0
0
Address = 00h, UNI Operating Mode Register