XRT79L71_1 Datasheet, PDF (140/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
REV. 1.0.0
BIT NUMBER
NAME
3
Auto Retransmit
2
Reserved
1
Transmit LAPD Message
Length
0
Transmit LAPD Enable
TYPE
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
Transmit LAPD Controller block to transmit PMDL messages,
repeatedly at one-second intervals. Once the user enables this
feature and then commands the Transmit LAPD Controller block
to transmit a given PMDL Message, the Transmit LAPD Control-
ler block 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
Transmit LAPD Controller block will proceed to transmit a contin-
uous 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 Trans-
mit LAPD Controller block will transmit PMDL messages (based
upon the contents within the Transmit LAPD Message Buffer)
repeatedly at one-second intervals.
NOTE: This bit-field is ignored if the Transmit LAPD Controller
block 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 Transmit LAPD Controller block to transmit a
LAPD/PMDL message that has a payload data size of 76 bytes.
1 - Configures the Transmit LAPD Controller block to transmit a
LAPD/PMDL message that has a payload data size of 82 bytes.
This bit-field is ignored if the Transmit LAPD Controller block is
disabled.
Transmit LAPD Controller Block Enable:
This READ/WRITE bit-field permits the user to enable the Trans-
mit LAPD Controller block, within the XRT79L7l device. Once
the user enables the Transmit LAPD Controller block, 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 Transmit LAPD Controller block will con-
tinue to repeatedly transmit the Flag Sequence octet until the
user commands the Transmit LAPD Controller block to transmit
a PMDL Message.
0 - Disables the Transmit LAPD Controller block.
1 - Enables the Transmit LAPD Controller block.
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