XRT79L71_1 Datasheet, PDF (159/434 Pages) Exar Corporation – 1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC -

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XRT79L71
1-CHANNEL DS3/E3 ATM UNI/PPP/CLEAR-CHANNEL FRAMER IC - REGISTER/MAP DESCRIPTION
Transmit DS3 F-Bit Mask # 4 Register (Address = 0x1139)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
F_Bit
Mask [7]/
UDL Bit # 3
(C23)
F_Bit
Mask [6]/
UDL Bit # 2
(C22)
F_Bit
Mask [5]/
UDL Bit # 1
(C21)
F_Bit
Mask [4]/X
Bit # 2
F_Bit
Mask [3]/
FEAC Bit
(C13)
R/W
R/W
R/W
R/W
R/W
0
0
0
0
0
BIT 2
BIT 1
F_Bit
F_Bit
Mask [2]/NA Mask [1]/AIC
Bit (C12)
Bit (C11)
BIT 0
F_Bit
Mask [0]/X
Bit # 1
R/W
R/W
R/W
0
0
0
BIT NUMBER
NAME
7
F Bit Mask[7]/UDL Bit # 3
(C23)
TYPE
R/W
DESCRIPTION
Transmit F-Bit Error - Bit 8/UDL Bit # 3 (C23):
The exact function of this register bit depends upon the following
parameters.
• Whether the XRT79L71 has been configured to operate in the
Clear-Channel Framer Mode, or not.
• Whether Bit 7 (TxOHSrc), within the Test Register (Address =
0x110C) is set to "1" or "0".
If the XRT79L71 is NOT configured to operate in the Clear-
Channel Framer Mode, OR if TxOHSrc = "0" - Transmit F-Bit
Error - Bit 8:
This READ/WRITE bit-field permits the user to configure the
Transmit DS3 Framer block to transmit DS3 frames with an
erred F bit.
This F-bit corresponds with the 8th F-bit, within a given outbound
DS3 frame. The Transmit DS3 Framer block will perform an
XOR operation with the contents of this bit-field and value of the
8th F-bit. The results of this calculation will be written back into
the 8th 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 the XRT79L71 is configured to operate in the Clear-Chan-
nel Framer Mode, AND if TxOHSrc = "1" - Insert Enable for
UDL Bit # 3 or C23 bit:
This READ/WRITE bit-field permits the user to configure the
Transmit Payload Data Input Interface block to externally accept
an overhead bit and insert it into the UDL Bit # 3 (or C23) bit-
fields, within the outbound DS3 data-stream.
0 - Configures the Transmit Direction circuitry to externally
accept and insert data into this overhead bit-field.
1- Configures the Transmit Direction circuitry to NOT externally
accept and insert data into this overhead bit-field.
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