XRT74L73 Datasheet, PDF (359/488 Pages) Exar Corporation – 3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER

PRELIMINARY
XRT74L73
3 CHANNEL, ATM UNI/PPP DS3/E3 FRAMING CONTROLLER
REV. P1.0.1
FIGURE 150. FLOW CHART DEPICTING THE FUNCTIONALITY OF THE LAPD RECEIVER
SSTTAARRTT
ENABLE THE LAPD RECEIVER
This is done by writing the value “xxxx x1xx” into
the RxLAPD Control Register (Address = 0x18)
LAPD Receiver begins reading in the N bits
from each inbound E3 frame
DDoeoses
thteheLLAAPPDD
RReceecievievrerdedteetcetct66
NO
coconnsesceucutitvieve
ZZereorsos
??
11
YES
AABBOORRTTSSeqequuenencece
DDoeoses
ththeeLLAAPPDD
RReceecievivererddeteetcetct77
coconnsesceuctuitvieve
ZZereorsos
YES
??
NO
FFlalgagSSeqeuqeunecnece
LLAAPPDDRReceecievievrerisisreraedadininggininaaLLAAPPDD
MMesessasgaegeFFrarmame,ec, ocnotnatianiinnigngaaPPMMDDLL
MMesessasgage.e.
DDoeoses
NO
ththeeLLAAPPDD
RReceecievievrerdedteetcetct66
coconnsesceucutitvivee
ZZereorsos
??
YES
EEndndofofMMesessasgaege(E(EOOMM) ₎
VVEERRIFIFYYTTHHEEFFCCSSVVAALLUUEE
RRepepoortrtrerseusultlstsininththeeRRxxLLAAPPDD
SStattautus _{sRRegegisitsetre.r...}
“U“Un-ns-tsutuffffcocnotnetnetnstsofofRReceecieviveded
MMesessasgaeg”e”
GGeneenreartaete“R“ReceecievievdedLLAAPPDD
InItnetrerrurputp”t”
DDoeoses
thteheLLAAPPDD
YES
RReceecievivererddeteetcetct77
coconnsesceuctuitvieve
ZZereorsos
??
NO
WWrirtieteRReceecievivededPPMMDDLLMMesessasgagee
inintotoththeeRReceecieviveeLLAAPPDDMMesessasgaege
BBuufffefrer(A(Addddrersessesses00xxDDEE- _{-00xx113355) )}
EExxeceucuteteRReceecievieveLLAAPPDD
InItnetrerruruptptSSerevrivcieceRRouotuitniene
11
5.3.4 The Receive Overhead Data Output Inter-
face
Figure 151 presents a simple illustration of the Re-
ceive Overhead Data Output Interface block within
the XRT74L73.
FIGURE 151. THE RECEIVE OVERHEAD OUTPUT INTERFACE BLOCK
RxOHFrame
RxOH
RxOHClk
RxOHEnable
Receive
Overhead Output
Interface Block
From Receive
E3 Framer Block
360