
á
á THREE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER XRT72L53
PRELIMINARY
REV. P1.1.7
120
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)
Bit 3 - Auto Retransmit
This Read/Write bit-field is used 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. 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 is used 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-
ting this bit-field to "1" configures the outbound LAPD
Message frame to be 82 bytes in length.
Bit 0 - TxLAPD Enable
This Read/Write bit-field is used 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 message)
via the outbound E3 frames, to the Remote Terminal.
Writing a "0" disables the LAPD Transmitter (default
condition). Writing a "1" enables the LAPD Transmit-
ter.
NOTE: For information on the LAPD Transmitter, please see
Section 4.2.3.
2.4.7.3
Transmit E3 LAPD Status and Interrupt
Register (ITU-T G.751)
Bit 3 - TxDL Start
This Read/Write bit-field is used to command the
LAPD Transmitter to do the following.
Scan through the PMDL Message, within the Trans-
mit LAPD Message buffer, and search for a string of
five (5) consecutive "1’s". The LAPD Transmitter will
then insert (or stuff) a "0" into the PMDL Message
TXE3 LAPD CONFIGURATION REGISTER (ADDRESS = 0X33)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
Not Used
Auto Retrans-
mit
Not Used
TxLAPD
Msg Length
TxLAPD
Enable
RO
R/W
RO
R/W
0
0001
000
TXE3 LAPD STATUS AND INTERRUPT REGISTER (ADDRESS = 0X34)
BIT 7BIT 6BIT 5BIT 4BIT 3BIT 2BIT 1BIT 0
Not Used
TXDL Start
TXDL Busy
TxLAPD
Interrupt
Enable
TxLAPD
Interrupt
Status
RO
R/W
RO
R/W
RUR
0
0000
000