XRT72L56 Datasheet, PDF (345/486 Pages) Exar Corporation – SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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PRELIMINARY
XRT72L56
SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. P1.1.2
FIGURE 143. 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
ththeeLLAAPPDD
RReceecievivererdedteetcetct66
NO
cocnonsesceucutitvieve
ZZereorsos
??
11
YES
AABBOORRTTSSeqequuenencece
DDoeoses
thteheLLAAPPDD
RReceecievievrerdedteetcetct77
cocnonsesceucutitvieve
ZZereorsos
YES
??
NO
FFlalgagSSeqeuqeunecnece
LLAAPPDDRReceecievievrerisisreraedadininggininaaLLAAPPDD
MMesessasgaegeFFrarmame,e,cocnontatianiinninggaaPPMMDDLL
MMesessasgaeg.e.
DDooeses
NO
ththeeLLAAPPDD
RReceecievivererdedteetcetct66
cocnonsesceucutitvieve
ZZereorsos
??
YES
EEndndofofMMesessasgaege(E(EOOMM) ₎
VVEERRIFIFYYTTHHEEFFCCSSVVAALLUUEE
RRepepoortrtrerseusultlstsininththeeRRxxLLAAPPDD
SStattautsusRRegegisitsetre.r...
“U“Un-ns-tsutfufffcocnotnetnetnstsofofRReceecievievded
MMesessasgaeg”e”
GGenenereartaete“R“ReceecievivededLLAAPPDD
InItnetrerrurputp”t”
DDoeoses
thteheLLAAPPDD
YES
RReceecievievrerdedteetcetct77
cocnonsesceucutitvieve
ZZereorsos
??
NO
WWrirtieteRReceecievivededPPMMDDLLMMesessasgagee
inintotoththeeRReceecieviveeLLAAPPDDMMesessasgaege
BBuufffefrer(A(Addddrersessesses0x0DxDEE- _{-0x01x3153)5)}
EExexceuctueteRReceecieviveeLLAAPPDD
InIntetrerruruppt _{tSSerevrivcieceRRooutuitninee}
11
5.3.4 The Receive Overhead Data Output Inter-
face
Figure 144 presents a simple illustration of the Re-
ceive Overhead Data Output Interface block within
the XRT72L56.
326