![](http://datasheet.mmic.net.cn/Exar-Corporation/XRT79L71IB-F_datasheet_100145/XRT79L71IB-F_29.png)
PRELIMINARY
XRT79L71
14
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
1.3
BRIEF FUNCTIONAL/ARCHITECTURAL DESCRIPTION OF THE XRT79L71 - ATM UNI OVER
DS3/E3 MODE
If the XRT79L71 has been configured to operate in the ATM UNI over DS3/E3 Mode, then it will have the
Functional Architecture as is presented below in Figure 4.
Figure 4 indicates that the XRT79L71 consists of the following functional blocks.
The Transmit UTOPIA Interface Block
The Transmit Overhead Data Input Interface Block
The Transmit ATM Cell Processor Block
The Transmit FEAC Controller Block (DS3 C-bit Parity Applications Only)
The Transmit Trail-Trace Message Controller Block (E3, ITU-T G.832 Applications Only)
The Transmit SSM Controller Block (E3, ITU-T G.832 Appications Only)
The Transmit LAPD Controller Block
The Transmit PLCP Processor Block
The Transmit DS3/E3 Framer Block
The Transmit DS3/E3 LIU Block
The Receive DS3/E3 LIU Block
The Receive DS3/E3 Framer Block
The Receive PLCP Processor Block
The Receive LAPD Controller Block
The Receive SSM Controller Block (E3, ITU-T G.832 Applications Only)
FIGURE 4. THE FUNCTIONAL BLOCK DIAGRAM OF THE XRT79L71 WHEN IT HAS BEEN CONFIGURED TO OPERATE IN
THE
ATM UNI OVER DS3/E3 MODE
Tx
UTOPIA
Interface
Block
Tx
UTOPIA
Interface
Block
Rx
UTOPIA
Interface
Block
Rx
UTOPIA
Interface
Block
Tx ATM
Cell
Processor
Block
Tx ATM
Cell
Processor
Block
Rx ATM
Cell
Processor
Block
Rx ATM
Cell
Processor
Block
Tx PLCP
Processor
Block
Tx PLCP
Processor
Block
Rx PLCP
Processor
Block
Rx PLCP
Processor
Block
Rx DS3/E3
Framer
Block
Rx DS3/E3
Framer
Block
Tx DS3/E3
Framer
Block
Tx DS3/E3
Framer
Block
Rx DS3/E3
LIU
Block
Rx DS3/E3
LIU
Block
Tx DS3/E3
LIU
Block
Tx DS3/E3
LIU
Block
DS3/E3
Jitter
Attenuator
Block
DS3/E3
Jitter
Attenuator
Block
DS3/E3
Jitter
Attenuator
Block
DS3/E3
Jitter
Attenuator
Block
Rx PLCP Processor Block
Can be by-passed for “Direct-Mapped”
ATM Applications
Tx PLCP Processor Block
Can be by-passed for “Direct-Mapped”
ATM Applications
Only one JA exists.
Can be configured in
Tx or Rx Path