3UsingtheDDR2MemoryController
3.1ConnectingtheDDR2MemoryControllertoDDR2SDRAM
UsingtheDDR2MemoryController
ThefollowingsectionsshowvariouswaystoconnecttheDDR2memorycontrollertoDDR2memory
devices.ThestepsrequiredtoconfiguretheDDR2memorycontrollerforexternalmemoryaccessare
alsodescribed.
Figure17,Figure18,andFigure19showahigh-levelviewofthethreememorytopologies
•A32-bitwideconfigurationinterfacingtotwo16-bitwideDDR2SDRAMdevices
•A16-bitwideconfigurationinterfacingtoasingle16-bitwideDDR2SDRAMdevice
•A16-bitwideconfigurationinterfacingtotwo8-bitwideDDR2SDRAMdevices
AllDDR2SDRAMdevicesmustbecomplainttotheJESD79D-2Astandard.
Notallofthememorytopologiesshownmaybesupportedbyyourdevice.Seethedevice-specificdata
manualformoreinformation.
Printedcircuitboard(PCB)layoutrulesandconnectionrequirementsbetweentheDSPandthememory
deviceexistandaredescribedinaseparatedocument.Seethedevice-specificdatamanualformore
information.TheODToutputpinsoftheDDR2memorycontrollermustnotbeconnectedtotheODTinput
pinsofDDR2memorydevices.Instead,theODTinputpinsoftheDDR2memorydevicesshouldbe
connectedtogroundandtheODToutputpinsoftheDDR2memorycontrollermustbeleftunconnected.
TheODToutputpinsoftheDDR2memorycontrollerarereservedforfutureuse.
SPRUEK5A–October2007DSPDDR2MemoryController29
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