XRT86L30
REV. 1.0.1
SINGLE T1/E1/J1 FRAMER/LIU COMBO
F
IGURE 21. E1 OVERHEAD
EXTERNAL DATALINK BUS
Non-FAS Frame
FAS Frame
TxSYNC
TxSER
TxOHclk
TxOH
Si
1
A Sa4 Sa5 Sa6 Sa7 Sa8
If Sa4, Sa7, and Sa8 are Selected
Sa4
Sa7 Sa8
4.11 Framer Bypass Mode
The framer bypass mode allows the XRT86L30 to be used as a stand alone Line Interface Unit. In this mode,
a few of the backplane interface signals multiplex into the digital Input/output signals to and from the LIU block.
Figure 22 shows a simplified block diagram of the framer bypass mode.
F
IGURE 22. SIMPLIFIED BLOCK DIAGRAM OF THE FRAMER BYPASS MODE
2-Frame
Slip Buffer
Elastic Store
TCLK=TxSERCLK
TPOS=TxSER
TNEG=TxSYNC
Tx Serial
Data In
Tx LIU
Interface
Tx Framer
Rx Framer
2-Frame
Slip Buffer
Elastic Store
RCLK=RxSERCLK
RPOS=RxSER
RNEG=RxSYNC
Rx Serial
Data Out
Rx LIU
Interface
154
EXAR [ EXAR CORPORATION ]
