XRT79L71 Datasheet, PDF (191/441 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
TXDS3 LAPD CONFIGURATION REGISTER (DIRECT ADDRESS = 0X1133)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
TxLAPD
Any
Unused
Auto
Retransmit
Reserved
R/W
R/O
R/O
R/O
R/W
R/O
0
0
0
0
1
0
XRT79L71
REV. P1.0.3
BIT 1
TxLAPD
Message
Length
R/W
0
BIT 0
TxLAPD
Enable
R/W
0
BIT NUMBER
NAME
7
TxLAPD Any
6-4
3
Unused
Auto Retransmit
2
Reserved
TYPE
R/W
R/O
R/W
R/O
DESCRIPTION
Transmit LAPD - Any kind:
This READ/WRITE bit-field permits the user to configure the
LAPD Transmitter to transmit any kind of LAPD Message (or
HDLC Message) with a size of 82 byte or less. If the user imple-
ments this option, then the LAPD Transmitter will be capable of
transmitting any kind of HDLC frame (with any value of header
bytes). The only restriction is that the size of the HDLC frame
must not exceed 82 bytes.
0 - Does not invoke this "Any Kind of HDLC Message" feature. In
this case, the LAPD Transmitter will only transmit HDLC Mes-
sages that contains the Bellcore GR-499-CORE values for SAPI
and TEI.
1- Invokes this "Any Kind of HDLC Message" feature. In this
case, the LAPD Transmitter will be able to transmit HDLC Mes-
sages that contain any header byte values.
NOTE:
If the user invokes the "Any Kind of HDLC Message"
feature, then he/she must indicate the size of the
information payload (in terms of bytes) within the
"Transmit LAPD Byte Count" Register (Direct Address
=0x1183).
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.
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