XR72L52 Datasheet, PDF (120/480 Pages) Exar Corporation – TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L52
REV. 1.0.1
xr
TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
Setting this bit-field to "1" configures the Transmit Section (of the chip) to transmit an "All Zeros" pattern (e.g.,
an LOS pattern) to the remote terminal.
NOTE: For more information on the LOS pattern, refer to Section 5.2.4.2.1.2.
Bit 0 - TxFAS Source Select
This Read/Write bit-field permits the user to configure the Transmit Section of the Channel to either:
a. Internally generate the FAS (Framing Alignment Signal) pattern, within the outbound E3 frames, or to
b. use the Input Interface as the source for the FAS pattern.
Setting this bit-field to "0" configures the Transmit Section of the Channel to internally generate the FAS pat-
tern, for each outbound E3 frame.
Setting this bit-field to "1" configures the Transmit Section of the Channel to use the Input Interface as the
source for the FAS pattern.
NOTE: For more information on the FAS pattern, refer to Section 5.1.
2.3.7.2 Transmit E3 LAPD Configuration Register (ITU-T G.751)
TXE3 LAPD CONFIGURATION REGISTER (ADDRESS = 0X33)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Not Used
Auto Retrans- Not Used
mit
TxLAPD
Msg Length
TxLAPD
Enable
RO
RO
RO
RO
R/W
RO
R/W
R/W
0
0
0
0
1
0
0
0
Bit 3 - Auto Retransmit
This Read/Write bit-field permits the user to configure the LAPD Transmitter to either transmit the LAPD Mes-
sage frame only once, or repeatedly at one-second intervals.
Writing a "0" to this bit-field configures the LAPD Transmitter to transmit the LAPD Message frame once. After-
wards, the LAPD Transmitter will halt transmission, until it has commanded to transmit another LAPD Message
frame.
Writing a "1" to this bit-field configures the LAPD Transmitter to transmit the LAPD Message frame repeatedly
at One-Second intervals. In this configuration, the LAPD Transmitter will repeat its transmission of the LAPD
Message frame until it has been disabled.
Bit 1 - TxLAPD Message Length Select
This Read/Write bit-field permits the user to select the length of the outbound LAPD Message frame.
Setting this bit-field to "0" configures the outbound LAPD Message frame to be 76 bytes in length. Setting this
bit-field to "1" configures the outbound LAPD Message frame to be 82 bytes in length.
NOTE: This should match with the message type of the LAPD message to be sent. (See Table 21 .)
Bit 0 - TxLAPD Enable
This Read/Write bit-field permits the user to enable or disable the LAPD Transmitter. The LAPD Transmitter
must be enabled before it can be commanded to transmit a LAPD Message frame (containing a PMDL mes-
sage) via the outbound E3 frames, to the Remote Terminal.
Writing a "0" disables the LAPD Transmitter (default condition). Writing a "1" enables the LAPD Transmitter.
NOTE: For information on the LAPD Transmitter, refer to Section 5.2.3.
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