XRT79L71 Datasheet, PDF (205/441 Pages) Exar Corporation – 1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC

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PRELIMINARY
1 - CHANNEL DS3/E3 ATM UNI/PPP COMBO IC
XRT79L71
REV. P1.0.3
BIT NUMBER
NAME
4
F Bit Mask [12]
3
F Bit Mask [11]/CP
Bit # 3 (C33)
TYPE
R/W
R/W
DESCRIPTION
Transmit F-Bit Error - Bit 13:
This READ/WRITE bit-field permits the user to configure the
Frame Generator block to transmit DS3 frames with an erred F
bit.
This F-bit corresponds with the 13th F-bit, within a given out-
bound DS3 frame. The Frame Generator block will perform an
XOR operation with the contents of this bit-field and value of the
13th F-bit. The results of this calculation will be written back into
the 13th F-bit position, within each outbound DS3 frame.
The user should set this bit-field to "0" for normal (e.g., un-erred)
operation.
Transmit F-Bit Error - Bit 12/CP Bit # 3 (C33):
The exact function of this register bit depends upon whether Bit 7
(TxOHSrc), within the "Test Register" (Direct Address = 0x110C)
is set to "1" or "0".
If "TxOHSrc" = 0 - Transmit F-Bit Error - Bit 12:
This READ/WRITE bit-field permits the user to configure the
Frame Generator block to transmit DS3 frames with an erred F
bit.
This F-bit corresponds with the 12th F-bit, within a given out-
bound DS3 frame. The Frame Generator block will perform an
XOR operation with the contents of this bit-field and value of the
12th F-bit. The results of this calculation will be written back into
the 12th F-bit position, within each outbound DS3 frame.
The user should set this bit-field to "0" for normal (e.g., un-erred)
operation.
If "TxOHSrc" = 1 - Insert Enable for CP Bit # 3 or C33 bit:
This READ/WRITE bit-field permits the user to configure the
Frame Generator block to externally accept an overhead bit and
insert it into the "CP Bit # 3 (or C33)" bit-fields, within the out-
bound DS3 data-stream.
0 - Configures the Frame Generator to externally accept and
insert data into this overhead bit-field.
1- Configures the Frame Generator to NOT externally accept
and insert data into this overhead bit-field.
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