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PRELIMINARY
DS3 UNI FOR ATM
XRT7245
REV. 1.03
115
Bit 1—TxFIFO Full
This “Read Only” bit-field indicates whether or not the
Tx FIFO (within the Transmit UTOPIA interface block)
is full. If this bit-field contains a “0” then the Tx FIFO
is NOT full. If this bit-field contains a “1”, then the
Tx FIFO IS full.
Bit 0—TxFIFO Empty
This “Read Only” bit-field indicates whether or not the
Tx FIFO (within the Transmit UTOPIA interface block)
is empty. If this bit-field contains a “0” then the Tx FIFO
is NOT empty. If this bit-field contains a “1”, then the
Tx FIFO IS empty.
3.3.2.114
Line Interface Drive Register
Bit 5—REQB (Receive Equalization Bypass
Control)
This “Read/Write” bit-field allows the user to control
the state of the REQB output pin of the UNI device.
This output pin is intended to be connected to the
REQB input pin of the XRT7300 DS3/E3 LIU IC. If
the user forcesss this signal to toggle “high”, then the
Receive Equalizer (within the XRT7300 device) willa
be disabled. Conversely, if the user forces this signal
to toggle “l(fā)ow”, then the Receive Equalizer (within the
XRT7300 device) will be enabled.
Writing a “1” to this bit-field causes the UNI device to
toggle the REQB output pin “high”. Writing a “0” to
this bit-field causes the UNI device to toggle the
REQB output pin “l(fā)ow”.
For information on the criteria that should be used
when deciding whether to bypass the equalization
circuitry or not, please consult the “XRT7300 DS3/
E3/STS-1 LIU IC” data sheet.
Note:
If the customer is not using the XRT7300 DS3/E3/
STS-1 LIU IC, then he/she can use this bit-field and the
REQB output pin for other purposes.
Bit 4—TAOS (Transmit All Ones Signal)
This “Read/Write” bit-field allows the user to control
the state of the TAOS output pin of the UNI device.
This output pin is intended to be connected to the
TAOS input pin of the XRT7300 DS3/E3 LIU IC. If the
user forces this signal to toggle “high”, then the
XRT7300 device will transmit an “All Ones” pattern
onto the line. Conversely, if the user commands this
output signal to toggle “l(fā)ow” then the XRT7300 LIU
IC will proceed to transmit data based upon the pat-
tern that it receives via the TxPOS and TxNEG out-
put pins (of the UNI IC).
Writing a “1” to this bit-field will cause the TAOS out-
put pin to toggle “high”. Writing a “0” to this bit-field
will cause this output pin to toggle “l(fā)ow”.
Note:
If the customer is not using the XRT7300 DS3/E3
LIU IC, then he/she can use this bit-field, and the TAOS
output pin for other purposes.
Bit 3—Encodis (B3ZS Encoder Disable)
This “Read/Write” bit-field allows the user to control the
state of the Encodis output pin of the UNI device. This
output pin is intended to be connected to the Encodis
input pin of the XRT7300 DS3/E3 LIU IC. If the user
forces this signal to toggle “high”, then the “internal
B3ZS encoder” (within the XRT7300 device) will be
disabled. Conversely, if the user command this output
signal to toggle “l(fā)ow”, then the “internal B3ZS encoder”
(within the XRT7300 device) will be enabled.
Writing a “1” to this bit-field causes the UNI IC to
toggle the “Encodis” output pin “high”. Writing a “0”
to this bit-field will cause the UNI IC to toggle this
output pin “l(fā)ow”.
Note:
3. The B3ZS encoder, within the XRT7300 device, is
not to be confused with the B3ZS encoding capa-
ble that exists within the Transmit DS3 Framer
block of the UNI IC.
4. The user is advised to disabled the B3ZS encoder
(within the XRT7300 IC) if the Transmit and
Receive DS3 Framers (within the UNI) are config-
ured to operate in the B3ZS line code.
5. If the customer is not using the XRT7300 DS3/E3
LIU IC, then he/she can use this bit-field and the
“Encodis” output pin for other purposes.
6. It is permissible to tie the “Encodis” output pin of
the XRT7245 DS3 UNI to both the “Encodis” and
“Decodis” input pins of the XRT7300 device.
Address = 72h, Line Interface Drive Register
B
IT
7
B
IT
6
B
IT
5
B
IT
4
B
IT
3
B
IT
2
B
IT
1
B
IT
0
Unused
REQB
TAOS
Encodis
TxLev
RLoop
LLoop
RO
RO
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
0
0
0