XRT79L71 Datasheet, PDF (217/441 Pages) Exar Corporation – 1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

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PRELIMINARY
1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
XRT79L71
REV. P1.0.3
TXE3 LAPD CONFIGURATION REGISTER - G.751 (DIRECT ADDRESS = 0X1133)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
Unused
Auto
Retransmit
Reserved
TxLAPD
Message
Length
R/O
R/O
R/O
R/O
R/W
R/O
R/W
0
0
0
0
1
0
0
BIT 0
TxLAPD
Enable
R/W
0
BIT NUMBER
NAME
7-4
Unused
3
Auto Retransmit
2
Reserved
1
TxLAPD Message
Length
0
TxLAPD Enable
TYPE
R/O
R/W
R/O
R/W
R/W
DESCRIPTION
Auto-Retransmit of LAPD Message:
This READ/WRITE bit-field permits the user to configure the
LAPD Transmitter to transmit PMDL messages, repeatedly at
one-second intervals. Once the user enables this feature, and
then commands the LAPD Transmitter to transmit a given PMDL
Message; the LAPD Transmitter will then proceed to transmit this
PMDL Message (based upon the contents within the Transmit
LAPD Message Buffer) repeatedly at one second intervals.
0 - Disables the Auto-Retransmit Feature. In this case, the
PMDL Message will only be transmitted once, afterwards the
LAPD Transmitter will proceed to transmit a continuous stream of
Flag Sequence octets (0x7E) via the DL bits, within each output
DS3 frame. No more PMDL Messages will be transmitted until
the user commands another transmission.
1 - Enables the Auto-Retransmit Feature.In this case, the LAPD
Transmitter will transmit PMDL messages (based upon the con-
tents within the Transmit LAPD Buffer) repeatedly at one-second
intervals.
NOTE: This bit-field is ignored if the LAPD Transmitter is
disabled.
Transmit LAPD Message Length Select:
This READ/WRITE bit-field permits the user to specify the length
of the payload data within the outbound LAPD/PMDL Message,
as indicated below.
0 - Configures the LAPD Transmitter to transmit a LAPD/PMDL
message that has a payload data size of 76 bytes.
1 - Configures the LAPD Transmitter to transmit a LAPD/PMDL
message that has a payload data size of 82 bytes.
LAPD Transmitter Enable:
This READ/WRITE bit-field permits the user to enable the LAPD
Transmitter, within the channel. Once the user enables the
LAPD Transmitter, it will immediately begin transmitting the Flag
Sequence octet (0x7E) to the remote terminal via the outbound
"DL" bits, within each DS3 data stream. The LAPD Transmitter
will continue to do this until the user commands the LAPD Trans-
mitter to transmit a PMDL Message.
0 - Disables the LAPD Transmitter.
1 - Enables the LAPD Transmitter.
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