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Raw FIFO
Raw 2 Raw 4 Raw 6Raw 1 Raw 3 Raw 5 Raw 7
VDIN[19−12] / VDIN[9−2]
VCLKINA
63 4847 32
Raw 2Raw 3
Raw 6Raw 7
Little-Endian Packing
Raw 8 Raw 10Raw 9 Raw 11Raw 0
31 1615 0
Raw 0Raw 1
Raw 4Raw 5
Raw 10Raw 11 Raw 8Raw 9
3.8TCICaptureMode
3.8.1TCICaptureFeatures
3.8.2TCIDataCapture
TCICaptureMode
Figure3-14.16-BitRawDataFIFOPacking
Thetransportchannelinterface(TCI)capturemodecapturesMPEG-2transportdata.
ThevideoportTCIcapturemodesupportsthefollowingfeatures:
•SupportsSYNCdetectusingthePACSTRTinputfromafront-enddevice.
•DatacaptureattherisingedgeofincomingVCLK1.
•Paralleldatareception.
•Maximumdatarateof30Mbytes/second.
•Programmablepacketsize.
•Hardwarecountermechanismtotimestampincomingpacketdata.
•Programmablefilteringofpacketswitherrors.
•InterrupttotheDSP,basedonabsolutesystemtimeorsystemtimeclockcycles.
Thevideoportdoesnotperformfollowingfunctions;thesefunctionsshouldbeperformedinsoftware:
•PIDfiltering
•Dataparsing
•De-scramblingofdata
Eight-bitparalleldataisreceivedontheinputdatabus.DataiscapturedontherisingedgeofVCLKIN.
Thedataconsiststypicallyof188-bytepackets,withthefirstbyteaSYNCbyte(alsocalledapreamble).
ThecapturepacketlengthisdeterminedbythevalueofVCASTOP.
DataonthedatabusisconsideredvalidandcapturedonlywhentheCAPENsignalisactive.TCIdata
capturebeginswithaSYNCbyteasindicatedbyPACSTRT(andCAPEN)active.(TheSYNCbytemay
haveanyvalue.)DataiscapturedoneachVCLKrisingedgewhenCAPENisactiveuntiltheentirepacket
hasbeencaptured,irrespectiveofadditionalPACSTRTtransitions.Theend-of-packetconditionoccurs
whenthe24-bitcapturebytecounter(asreflectedbytheVCYPOSandVCXPOSbitsofVCASTAT)
equalsthevalueintheVCYSTOPandVCXSTOPbitsofVCASTOP.Thecaptureddataincludesboth
SYNCbyteandthedatapayloadasshowninFigure3-15.
Afterapacketiscaptured,thevideoportwaitsforthenextactivePACSTRTtobegincaptureofanother
packet.Receivedpacketdataispackedinto64bitsbeforebeingwrittentotheFIFO.
SPRUEM1–May2007VideoCapturePort63
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