Texas Instruments TMS320DM355 Computer Hardware User Manual


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PRODUCT PREVIEW
DIN<9:0>
DACDigitalInput
C
BG
0.1 Fm
VREF
VideoDACandBuffer
R
BIAS
2550 Ω
IBIAS
R
fb
= 1000 Ω
IOUT VFB TVOUT
R
out
=1070 Ω
TVmonitor
TVOUT[V]
VideoBufferOutputVoltage
MSB
LSB
V
OL(VIDBUF)
V
OH(VIDBUF)
0
TMS320DM355
DigitalMediaSystem-on-Chip(DMSoC)
SPRS463A–SEPTEMBER2007–REVISEDSEPTEMBER2007
A.PlacecapacitorsandresistorsascloseaspossibletotheDM355.
B.Youmustusethecircuitshowninthisdiagram.AlsoyoumustconfiguretheVDAC_CONFIGregisterintheSystem
Controlmoduleasfollows:TRESB4R4=0x3,TRESB4R2=0x8,TRESB4R1=0x8,TRIMBITS=0x34,PWD_BGZ=
1(powerupVREF),SPEED=1(faster),TVINT=don'tcare,PWD_VBUFZ=1(powerupvideobuffer),VREFSET=
don'tcare,ACCUP_EN=0(noA/Ccoupling),DINV=1(invert).SeetheTMS320DM355ARMSubsystemReference
GuideandtheTMS320DM355DMSoCVideoProcessingBackEnd(VPBE)User'sGuideformoreinformationonthe
VDAC_CONFIGregisterandVideoBuffer.
C.ForproperTVOUTvoltage,youmustconnectthepinTVOUTdirectlytotheTV.NoA/Ccouplingcapacitoror
terminationresistorisnecessaryonyourDM355board.Also,itisassumedthattheTVhasnointernalA/Ccoupling
capacitorbutdoeshaveaninternalterminationresistor,asshowninthisdiagram.TVOUTvoltagewillrangefrom
V
OL(VIDBUF)
toV
OH(VIDBUF)
.SeeSection4.3forthevoltagespecifications.
Figure5-32.DACWithBufferCircuit
126PeripheralInformationandElectricalSpecificationsSubmitDocumentationFeedback
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