XR72L52 Datasheet, PDF (203/480 Pages) Exar Corporation – TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

xr
TWO CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
XRT72L52
REV. 1.0.1
The purpose of this interrupt is to alert the Microcontroller/MIcroprocessor that the LAPD Transmitter has com-
pleted its transmission of a given LAPD (or PMDL) Message, and is now ready to transmit the next PMDL Mes-
sage, to the Remote Terminal Equipment.
4.3 THE RECEIVE SECTION OF THE XRT72L52 (DS3 MODE OPERATION)
When the XRT72L52 has been configured to operate in the DS3 Mode, the Receive Section of the XRT72L52
consists of the following functional blocks.
• Receive LIU Interface block
• Receive HDLC Controller block
• Receive DS3 Framer block
• Receive Overhead Data Output Interface block
• Receive Payload Data Output Interface block
Figure 60 presents a simple illustration of the Receive Section of the XRT72L52 Framer IC.
FIGURE 60. THE XRT72L52 RECEIVE SECTION CONFIGURED TO OPERATE IN THE DS3 MODE
RxOHFrame
RxOHEnable
RxOH
RxOHClk
Receive
OverhReeacdeIinvpeut
InOtevrfearcheeBadloIcnkput
Interface Block
RxOHInd
RxSer
RxNib[3:0]
RxClk
RxFrame
Receive
PayloRaedcDeiaveta
PaInyplouatd Data
InterfacInepBultock
Interface Block
Receive DS3/E3
FRraemceeirveBDloSck3/E3
Framer Block
Receive LIU
IRnteecrefaivceeLIU
BInlotecrkface
Block
RxPOS
RxNEG
RxLineClk
From Microprocessor
Interface Block
Receive DS3
RHeDceLiCve DS3
ControlHleDr/LBCuffer
Controller/Buffer
Each of these functional blocks will be discussed in detail in this document.
4.3.1 The Receive DS3 LIU Interface Block
The purpose of the Receive DS3 LIU Interface block is two-fold:
1. To receive encoded digital data from the DS3 LIU IC.
2. To decode this data, convert it into a binary data stream and to route this data to the Receive DS3 Framer
block.
Figure 61 presents a simple illustration of the Receive DS3 LIU Interface block.
187