XR72L52 Datasheet, PDF (190/480 Pages) Exar Corporation – TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L52
REV. 1.0.1
xr
TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
4.2.4.2.1.1 Transmit Yellow Alarm - Bit 7
This read/write bit field permits the user to force the transmission of a Yellow Alarm to the remote terminal
equipment via software control. If the user opts to transmit a Yellow Alarm then both of the X-bits, within the
outbound DS3 frames will be set to '0'. Table 24 relates the content of this bit field to the Transmit DS3 Framer
block's action.
TABLE 24: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 7 (TX YELLOW ALARM) WITHIN THE TX DS3
CONFIGURATION REGISTER, AND THE RESULTING TRANSMIT DS3 FRAMER BLOCK'S ACTION
BIT 7
0
1
TRANSMIT DS3 FRAMER'S ACTION
Normal Operation:
The X-bits are generated by the Transmit DS3 Framer block based upon Near End Receiving Conditions (as
detected by the Receive Section of the chip)
Transmit Yellow Alarm:
The Transmit DS3 Framer block will overwrite the X-bits by setting them all to 0. The payload information is
not modified and is transmitted as normal.
NOTE: This bit is ignored when either the TxIDLE, TxAIS, or the TxLOS bit-fields are set.
4.2.4.2.1.2 Transmit X-bit - Bit 6
This bit field functions as the logical complement to Bit 7 (e.g., Tx Yellow Alarm). This read/write bit field per-
mits the user to force all of the X-bits, in the outbound DS3 frames, to "1" and transmit them to the remote ter-
minal equipment. Table 25 relates the content of this bit field to the Transmit DS3 Framer Block's action.
TABLE 25: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 6 (TX X-BITS) WITHIN THE TX DS3 CONFIGURATION
REGISTER, AND THE RESULTING TRANSMIT DS3 FRAMER BLOCK'S ACTION
BIT 6
0
1
TRANSMIT DS3 FRAMER'S ACTION
Normal Operation:
The X-bits are generated by the Transmit DS3 Framer block based upon Receiving Conditions (as detected
by the Receive Section of the Framer chip).
Set X-bits to 1:
The Transmit DS3 Framer will overwrite the X-bits by setting them to 1. Payload information is not modified
and is transmitted as normal.
NOTE: This bit is ignored when either the Transmit Yellow Alarm, Tx AIS, Tx IDLE, or TxLOS bit is set.
4.2.4.2.1.3 Transmit Idle Pattern - Bit 5
This read/write bit field permits the user to transmit an Idle pattern to the remote terminal equipment upon soft-
ware control. Table 26 relates the contents of this bit field to the Transmit DS3 Framer's action.
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