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PRELIMINARY
XRT79L71
146
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
4.2.5.5
SETTING X BITS TO "1"
The Transmit DS3 Framer block permits the user to force all of the X bits to "1". This bit field functions as the
logical inverse of Bit 7 (Tx FERF Indicator). The user can accomplish this by setting Bit 6 (Tx X Bits) within the
Transmit DS3 Configuration Register, to "1" as illustrated below.
This read/write bit field permits the user to force each of the X-bits, in each outbound DS3 frame, to "1" and
transmit them to the remote terminal equipment.
NOTE: This bit is ignored when either the Transmit FERF Indicator, Tx AIS, Tx IDLE, or TxLOS bit is set.
4.2.5.6
TRANSMITTING THE FEBE (FAR-END BLOCK ERROR) INDICATOR
If the Transmit DS3/E3 Framer block is configured to support the DS3, C-bit Parity framing format, then it will
be capable of transmitting the FEBE (Far-End-Block-Error) indicator to the remote terminal equipment.
The purpose of the FEBE bit-fields, within the DS3 frame is two-fold.
FIGURE 62. ILLUSTRATION OF THE NEAR-END TRANSMIT DS3/E3 FRAMER BLOCK, TRANSMITTING A DS3 FRAME TO
THE REMOTE TERMINAL EQUIPMENT WITH EACH OF THE
X BITS SET TO "1"
Transmit DS3 Configuration Register (Indirect Address = 0xNE, 0x30; Direct Address = 0x1130)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Tx FERF
Indicator
Tx X-Bits
TxIdle
TxAIS
TxLOS
TxFERF upon
LOS
TxFERF upon
OOF
TxFERF upon
AIS
R/W
0
1
0
1
Transmit Payload
Data Input
Interface Block
Transmit DS3/E3
Framer Block
DS3/E3
Jitter
Attenuator
Block
DS3/E3
Jitter
Attenuator
Block
DS3/E3
Jitter
Attenuator
Block
DS3/E3
Jitter
Attenuator
Block
Receive DS3/E3
Framer Block
Receive Payload
Data Output
Interface Block
Microprocessor
Interface
TxSer
TxNib[3:0]
TxInClk
MOTO
D[7:0]
A[8:0]
IntB*
CSB*
RdB_DS
WrB_RW
Rdy_Dtck
Reset*
ALE_AS
RxSer
RxNib[3:0]
RxOutClk
Tx LAPD Buffer/
Controller
Rx LAPD Buffer/
Controller
Transmit Overhead
Input
Interface Block
Receive Overhead
Output
Interface Block
TxOHClk
TxOHIns
TxOHInd
TxOH
TxOHEnable
TxOHFrame
TxNibClk
TxFrame
RxNibClk
RxFrame
RxOHFrame
RxOH
RxOHClk
RxOHEnable
RxOHInd
Transmit
DS3/E3
LIU Block
Transmit
DS3/E3
LIU Block
Receive
DS3/E3
LIU Block
Receive
DS3/E3
LIU Block
TTIP
TRING
RTIP
RRING
Only one JA exists.
Can be configured in
Tx or Rx Path
No Defects Declared
1
Next Outbound
DS3 Frame
X-bits are set to“1” to
denote Normal Condition
1