XRT74L74 Datasheet, PDF (395/498 Pages) Exar Corporation – 4 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER

PRELIMINARY
XRT74L74
4 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
REV. P1.1.1
FIGURE 162. THE TRANSMIT SECTION WHEN IT HAS BEEN CONFIGURED TO OPERATE IN THE E3 MODE
TxOHFrame
TxOHEnable
TxOH
TxOHClk
TxOHIns
TxOHInd
TxSer
TxNib[3:0]
TxInClk
TxNibClk
TxFrame
Transmit
OverhTeraandsInmpiut t
InOtevrfearcheeBadloIcnkput
Interface Block
Transmit
PaylToaradnDsamtait
PaInyplouatd Data
InterfacInepBulot ck
Interface Block
Transmit DS3/E3
FTrraamnsemr BitlDocSk3/E3
Framer Block
Transmit LIU
ITnrtaenrfsamceit ^LIU
BInlotecrkface
Block
TxPOS
TxNEG
TxLineClk
From Microprocessor
Interface Block
Transmit E3
THraDnLsCmit E3
ControlHleDr/LBCuffer
Controller/Buffer
Each of these functional blocks will be discussed in
detail in this document.
7.2.1 The Transmit Payload Data Input Inter-
face Block
Figure 163 presents a simple illustration of the
Transmit Payload Data Input Interface block.
FIGURE 163. THE TRANSMIT PAYLOAD DATA INPUT INTERFACE BLOCK
TxOH_Ind
TxSer
TxNib[3:0]
TxInClk
TxNibClk
TxFrame
TxFrameRef
Transmit
Payload Data
Input Interface
Block
To Transmit E3
Framer Block
Each of the input and output pins of the Transmit Pay-
load Data Input Interface are listed in Table 86 and
described below. The exact role that each of these
inputs and output pins assume, for a variety of oper-
ating scenarios are described throughout this section.
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