XRT72L56 Datasheet, PDF (122/486 Pages) Exar Corporation – SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L56 SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
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PRELIMINARY
• Serially transmit this 16-bit FEAC Message to the
far-end receiver via the outbound DS3 data-stream,
10 consecutive times.
NOTE: For more information on the Transmit FEAC Proces-
sor, please see Section 3.2.3.1.
Bit 0 - TxFEAC Busy
This Read-Only bit-field allows the local µP to poll
and determine if the Transmit FEAC Processor has
completed its 10th transmission of the 16-bit FEAC
Message. This bit-field will contain a "1", if the Trans-
mit FEAC Processor is still transmitting the FEAC
Message. This bit-field will toggle to "0", once the
Transmit FEAC Processor has completed its 10th
transmission of the FEAC Message.
NOTE: For more information on the Transmit FEAC Proces-
sor, please see Section 3.2.3.1.
2.4.5.3 Transmit DS3 FEAC Register (DS3
Applications)
TXDS3 FEAC REGISTER (ADDRESS = 0X32)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
Not Used
TxFEAC[5:0]
RO
R/W
R/W
R/W
R/W
0
1
1
1
1
BIT 2
R/W
1
BIT 1
R/W
1
BIT 0
Not Used
RO
0
This register contains a six (6) bit read/write field that
allows the user to write in the six-bit FEAC code word,
that is desired to be transmitted to the Far End Re-
ceive FEAC Processor, via the outgoing DS3 data
stream. The Transmit FEAC Processor will encapsu-
late this six-bit code into a 16-bit FEAC message, and
will proceed to transmit this message to the Remote
Receiver via the FEAC bit-field within each out-going
DS3 frame.
NOTE: For more information on the operation of the Trans-
mit FEAC Processor, please see Section 3.2.3.1.
2.4.5.4 Transmit DS3 LAPD Configuration
Register (DS3 Applications)
TXDS3 LAPD CONFIGURATION REGISTER (ADDRESS = 0X33)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Not Used
Auto
Retransmit
Not Used TxLAPD Msg TxLAPD
Length
Enable
RO
R/W
R/W
R/W
R/W
R/W
R/W
RO
0
0
0
0
1
0
0
0
Bit 3 - Auto Retransmit
This Read/Write bit-field allows the user to configure
the LAPD Transmitter to either transmit the LAPD
Message frame only once or, repeatedly at one-sec-
ond 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 permits the user 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 allows the user 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 DS3 frames, to the Far-
End Terminal.
Writing a “0" disables the LAPD Transmitter (default
condition). Writing a "1" enables the LAPD Transmit-
ter.
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