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4.12VTPIOControlRegister(VTPIOCR)
DDR2MemoryControllerRegisters
TheVTPIOcontrolregister(VTPIOCR)isusedtocontrolthecalibrationoftheDDR2memorycontroller
IOswithrespecttovoltage,temperature,andprocess(VTP).Thevoltage,temperature,andprocess
informationisusedtocontroltheIO'soutputimpedance.TheVTPIOCRisshowninFigure30and
describedinTable36.
Figure30.VTPIOControlRegister(VTPIOCR)
3116
Reserved
R-0
1514131211109540
RECALRsvdENReservedRsvdPCHNCH
R/W-0R/W-0R/W-0R/W-0R-0R/W-0R/W-1Fh
LEGEND:R/W=Read/Write;R=Readonly;-n=valueafterreset
Table36.VTPIOControlRegister(VTPIOCR)FieldDescriptions
BitFieldValueDescription
31-16Reserved0Reserved
15RECALStartVTPIOcalibration.
0Normaloperation
1Transitionfrom0to1startsVTPIOcalibration.
14Reserved0Reserved.Alwayswritea0tothisbit.
13ENVTPenable.
0VTPIOcalibrationisdisabled.
1VTPIOcalibrationisenabled.
12-11Reserved0Reserved.Alwayswritea0tothisbit.
10Reserved0Reserved
9-5PCH0-1FhPchannelvalue.ThisvalueisdriventotheIOtocalibratetheimpedanceoftheIO.ThevalueofPCH
isdeterminedbyreadingtheDDRVTPregister(DDRVTPR).SeeSection4.13fordetails.
4-0NCH0-1FhNchannelvalue.ThisvalueisdriventotheIOtocalibratetheimpedanceoftheIO.ThevalueofNCH
isdeterminedbyreadingtheDDRVTPregister(DDRVTPR).SeeSection4.13fordetails.
SPRU986B–November2007DDR2MemoryController53
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