XRT7250 Datasheet, PDF (190/463 Pages) Exar Corporation – DS3/E3 FRAMER IC

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DS3/E3 FRAMER IC
XRT7250
REV. 1.1.1
TABLE 30: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 4 (TX AIS PATTERN) WITHIN THE TX DS3
CONFIGURATION REGISTER, AND THE RESULTING TRANSMIT DS3 FRAMER BLOCK'S ACTION
BIT 4
TRANSMIT DS3 FRAMER'S ACTION
0 _{Normal Operation:}
The Overhead bits are either internally generated, or they are inserted via the Transmit Overhead Data Input
Interface or the Transmit HDLC Controller blocks. The Payload bits are received from the Transmit Payload Data
Input Interface.
1 _{Transmit AIS Pattern:}
When this command is invoked, the Transmit DS3 Framer block will do the following.
• Set the X-bits to 1
• Set all the C-bits to 0
• Generate valid M, F, and P bits
Overwrite the data in the DS3 payload with a repeating 1010... pattern
NOTE: This bit is ignored when the TxLOS bit is set.
4.2.4.2.1.5 Transmit LOS Pattern - Bit 3
This read/write bit field allows the user to transmit an
LOS (Loss of Signal) pattern to the remote terminal,
upon software control. Table 31 relates the contents
of this bit field to the Transmit DS3 Framer block's ac-
tion.
TABLE 31: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 3 (TX LOS) WITHIN THE TX DS3 CONFIGURATION
REGISTER, AND THE RESULTING TRANSMIT DS3 FRAMER BLOCK'S ACTION
BIT 3
0
1
TRANSMIT DS3 FRAMER'S ACTION
Normal Operation:
The Overhead bits are either internally generated, or they are inserted via the Transmit Overhead Data Input
Interface or the Transmit HDLC Controller blocks. The Payload bits are received from the Transmit Payload
Data Input Interface.
Transmit LOS Pattern:
When this command is invoked the Transmit DS3 Framer will do the following.
• Set all of the overhead bits to "0" (including the M, F, and P bits)
Overwrite the DS3 payload bits with an all zeros pattern.
NOTE: When this bit is set, it overrides all of the other bits in
this register.
4.2.4.2.1.6 FERF (Far-End Receive Failure) on
LOS - Bit 2
This Read/Write bit-field allows the user to configure
the Transmit DS3 Framer block to automatically gen-
erate a Yellow Alarm if the Near-End Receive Section
(of the XRT7250) detects a LOS (Loss of Signal)
Condition.
Writing a "1" to this bit-field enables this feature. Writ-
ing a "0" to this bit-field disables this feature.
4.2.4.2.1.7 FERF (Far-End Receive Failure) on
OOF - Bit 1
This Read/Write bit-field allows the user to configure
the Transmit DS3 Framer block to automatically gen-
erate a Yellow Alarm if the Near-End Receive Section
(of the XRT7250) detects an OOF (Out-of-Frame)
Condition.
Writing a "1" to this bit-field enables this feature. Writ-
ing a "0" to this bit-field disables this feature.
4.2.4.2.1.8 FERF (Far-End Receive Failure) on
AIS - Bit 0
This Read/Write bit-field allows the user to configure
the Transmit DS3 Framer block to automatically gen-
erate a Yellow Alarm if the Near-End Receive Section
(of the XRT7250) detects an AIS (Alarm Indication
Signal) pattern.
Writing a "1" to this bit-field enables this feature. Writ-
ing a "0" to this bit-field disables this feature.
4.2.4.2.1.9 Transmitting FEBE (Far-End Block
Error) Values
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