XRT72L52 Datasheet, PDF (132/480 Pages) Exar Corporation – TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L52 TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.3
áç
PRELIMINARY
TXNSOURCESEL[1:0]
SOURCE OF N BIT
01
Transmit Overhead Data Input Interface
10
Transmit LAPD Controller
11
Transmit Payload Data Input Interface.
NOTE: For more information on the N-bit, within the ITU-T
G.751 frame, please see Section 4.1.1.2.
Bit 2 - TxAIS Enable
This Read/Write bit-field permits the user to configure
the Transmit Section of the Framer IC to transmit an
AIS pattern to the remote terminal
Setting this bit-field to "0" configures the Transmit
Section (of the chip) to transmit data in a normal man-
ner (e.g., as received via the Input Interface).
Setting this bit-field to "1" configures the Transmit
Section (of the chip) to transmit an "All Ones" pattern
(e.g., an AIS pattern) to the remote terminal.
NOTE: For more information on the AIS pattern, please see
Section 4.2.4.2.1.1.
Bit 1 - TxLOS Enable
This Read/Write bit-field permits the user to configure
the Transmit Section of the Framer IC to transmit an
LOS (e.g., All Zeros) pattern to the remote terminal
Setting this bit-field to "0" configures the Transmit
Section (of the chip) to transmit data in a normal man-
ner (e.g., as received via the Input Interface).
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, please
see Section 4.2.4.2.1.2.
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
pattern, 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, please see
Section 4.1.
2.4.7.2 Transmit E3 LAPD Configuration Reg-
ister (ITU-T G.751)
TXE3 LAPD CONFIGURATION REGISTER (ADDRESS = 0X33)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
Not Used
Auto Retrans- Not Used
mit
RO
RO
RO
RO
R/W
RO
0
0
0
0
1
0
BIT 1
TxLAPD
Msg Length
R/W
0
BIT 0
TxLAPD
Enable
R/W
0
Bit 3 - Auto Retransmit
This Read/Write bit-field permits the user to configure
the LAPD Transmitter to either transmit the LAPD
Message frame only once, or repeatedly at one-sec-
ond intervals.
Writing a "0" to this bit-field configures the LAPD
Transmitter to transmit the LAPD Message frame
once. Afterwards, the LAPD Transmitter will halt
transmission, until it has commanded to transmit an-
other LAPD Message frame.
Writing a "1" to this bit-field configures the LAPD
Transmitter to transmit the LAPD Message frame re-
peatedly at One-Second intervals. In this configura-
tion, the LAPD Transmitter will repeat its transmission
of the LAPD Message frame until it has been dis-
abled.
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. Set-
113