XRT72L50 Datasheet, PDF (96/471 Pages) Exar Corporation – SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER WITH HDLC CONTROLLER
REV. 1.2.1
2.3.4.9 Receive E3 Service Bits Register (E3, ITU-T G.751)
RxE3 Service Bit Register (Address = 0x1A)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
Not Used
RO
RO
RO
RO
RO
0
0
0
0
0
BIT 2
RO
0
áç
BIT 1
RxA
RO
0
BIT 0
RxN
RO
0
Bit 1 - RxA (A-Bit)
This Read-Only bit-field reflects the state of the A-Bit-field, within the most recently received E3 frame.
Bit 0 - RxN (N-Bit)
This Read-Only bit-field reflects the state of the N-Bit-field, within the most recently received E3 frame.
2.3.5 Transmit DS3 Configuration Registers
2.3.5.1 Transmit DS3 Configuration Register
Transmit DS3 Configuration Register (Address = 0x30)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Tx Yellow
Alarm
Tx X Bits
Tx Idle
Tx AIS
Tx LOS
FERF on
LOS
FERF on
OOF
FERF on
AIS
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
1
1
1
Bit 7 - Tx Yellow Alarm
This Read/Write bit-field permits the user to command the Transmit DS3/E3 Framer block to transmit a Yellow
Alarm (e.g., X bits are all "0") in the outbound DS3 data stream.
Writing a "0" to this bit-field disables this feature (the default condition). In this condition, the X-bits in the out-
bound DS3 frame, are internally generated (based upon receiver conditions).
Writing a "1" to this bit-field invokes this command. In this condition, the Transmit DS3/E3 Framer block will
override the internally-generated X-bits and force all of the X-bits of each outbound DS3 frame to "0".
NOTES:
1. For more information in this feature, refer to Section 4.2.4.2.1.1.
2. This bit-setting is ignored if Bits 3, 4 or 5 (within this register) are set to "1".
Bit 6 - Tx X-Bit (Force X bits to "1")
This "Read/Write" bit-field permits the user to command the Transmit DS3/E3 Framer block to force all of the X-
bits, in the outbound DS3 Frames, to "1".
Writing a "0" to this bit-field disables this feature (the default condition). In this case, the Transmit DS3/E3
Framer block will generate X-bits based upon the receive conditions.
Writing a "1" to this bit-field invokes this command. In this case, the Transmit DS3/E3 Framer block will
overwrite the internally-generated X-bits and set them all to "1".
NOTES:
1. For more information on this feature, refer to Section 4.2.4.2.1.2.
2. This bit-setting is ignored if Bits 3, 4, 5, or 7 (within this register) are set to "1".
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