www.德州仪器.com
s0078-01
V
CC
V
EE
VT = v
CC
–
2V
CDCM7005
驱动器
LVPECL
接受者
Z = 50
O
50
50
Z = 50
O
Yx
Yx
SPICONTROLINTERFACE
CDCM7005
SCAS793A–JUNE2005–REVISEDJUNE2005
parametermeasurementinformation(持续)
figure13.lvpecloutputloadingduringdevicetest
theserialinterfaceofthecdcm7005isasimplespi-compatibleinterfaceforwritingtotheregistersofthe
deviceandconsistsofthreecontrollines:ctrl_clk,ctrl_数据,andctrl_le.therearefour32-bitwide
寄存器,whichcanbeaddressedbythetwolsbsofatransferredword(bit0andbit1).everytransmittedword
musthave32bits,startingwithmsbfirst.eachwordcanbewrittenseparately.bit7,8,10,andbit12to31of
word3arereservedforfactorytestpurposesandmustbefilledwithzeros.thetransferisinitiatedwiththe
fallingedgeofctrl_le;aslongasctrl_leishigh,nodatacanbetransferred.duringctrl_le,lowdata
canbewritten.thedatahastobeappliedatctrl_dataandhastobestablebeforetherisingedgeof
ctrl_clk.thetransmissionisfinishedbyarisingedgeofctrl_le.withtherisingedgeofctrl_le,这
newwordisasynchronouslytransferredtotheinternalregister(e.g.,n,m,p,...).eachwordhastobe
separatelytransmittedbythisprocedure.
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