XRT79L71_1 Datasheet, PDF (177/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

REV. 1.0.0
XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
BIT NUMBER
NAME
0
Transmit LAPD Enable
TYPE
R/W
DESCRIPTION
Transmit LAPD Controller Block Enable:
This READ/WRITE bit-field permits the user to enable the Trans-
mit LAPD Controller block, within the XRT79L71. Once the user
enables the Transmit LAPD Controller block, it will immediately
begin transmitting the Flag Sequence octet (0x7E) to the remote
terminal via either the NR or the GC bytes, within the outbound
E3 data stream. The Transmit LAPD Controller block will con-
tinue to do this 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.
Transmit E3 LAPD Status/Interrupt Register - G.832 (Address = 0x1134)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
Unused
Initiate
Transmis-
sion
of
LAPD/PMDL
Message
Transmit
LAPD
Controller
Busy
R/O
R/O
R/O
R/O
R/W
R/O
0
0
0
0
0
0
BIT 1
Transmit
LAPD
Interrupt
Enable
R/W
0
BIT 0
Transmit
LAPD
Interrupt
Status
RUR
0
BIT NUMBER
NAME
7-4
Unused
3
Initiate Transmission of
LAPD/PMDL Message
TYPE
R/O
R/W
DESCRIPTION
Transmit LAPD Message Command:
A "0" to "1" transition, within this bit-field commands the Transmit
LAPD Controller block to begin the following activities:
• Reading out the contents of the Transmit LAPD Message
Buffer.·
• Zero-Stuffing of this data· FCS Calculation and Insertion
• Fragmentation of this composite PMDL Message, and
insertion into either the NR or GC byte-fields, within each
outbound E3 frame.
NOTE: This bit-field is only active if the Transmit LAPD Controller
block has been enabled.
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