Intel微机原理第10章（存储器接口）ppt课件.ppt

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1、MemoryInterface本章要求掌握各种存储器器件、译码方法、时序及其接口原理1.MemoryDevicesRAMSRAMDRAMROMROMPROMEPROMEEPROM(FlashMemory)存储器引脚地址线----Allmemorydeviceshaveaddressinputsselectamemorylocation.Threemainpoints:•arrangenumber•thenumberofmemorylocationsfound•firstaddressandlasta

2、ddress数据线----Allmemorydeviceshaveasetofdatainput/output.twomainpoints:•utility•cataloglisting选择线----Eachmemorydevicehasatleastonechipselect(CS)orchipenable(CE)pinthatenablesthememorydevice.twomainpoints:•activelevel•morethanoneconnection控制线----Eachmemo

3、rydevicehasatleastonecontrolpin.ForROMs,anoutputenable(OE)orgate(G)ispresent.ForRAMs,aread-write(R/W)orwriteenable(WE)andreadenable(OE)arepresent.twomainpoints:•ROMcontrolconnection•RAMcontrolconnection存储器引脚图EPROM2716(2kX8)2716读时序SRAM4016(2Kx8)DRAM4464

4、(64KX4)4464时序SRAM和DRAMSRAMsarelimitedinsize(upto128KX8).DRAMsareavailableinmuchlargersizes,e.g.,16MX1,64MX1256MX1.DRAMsmustberefreshedevery2to4ms.DRAMsaretypicallyplacedonSIMM(SingleIn-lineMemoryModules)boards.（单列直插式存储器模块）30-pinSIMMscomein1MX8,1MX9(par

5、ity),4MX8,4MX9.72-pinSIMMscomein1/2/3/8/16MX32or1MX36(parity).Seep343fig.10-11SIMM和DIMMPentiumshavea64-bitwidedatabus.64-bitDIMMs(DualIn-lineMemoryModules)arethestandard.（双列直插式存储器模块）TheboardhasDRAMsmountedonbothsidesandis168pins.Sizesinclude2MX64(16M),

6、4MX64(32M),8MX64(64M)and16MX64(128M).Seep344fig.10-12TheDIMMmoduleisavailableinDRAM,EDOandSDRAMwithandwithoutanEPROM.TheEPROMprovidesinformationaboutthesizeandspeedofthememorydeviceforPNPapplications.10-2地址译码存储器地址译码使存储器工作在存储器映射表中独立的区域，CPU按地址访问其存储单元(loc

7、ation),访问方法可采用字节寻址或字寻址。地址译码需要地址译码器，CPU的地址线通过地址译码器与存储器连接。地址译码可采用3-8译码器、PROM地址译码器、PLD地址译码器等技术。简单的与非门译码器地址分布3-8译码器译码电路PROM地址译码器TPB28L42(512X8)PLD可编程译码器PLDscomeinthreevarieties:•PLA(ProgrammableLogicArray)•PAL(ProgrammableArrayLogic)•GAL(GatedArrayLogic)AP

8、ALexample(16L8)isshowninthetextandiscommonlyusedtodecodethememoryaddress,particularlyfor32-bitaddressesgeneratedbythe80386DXandabove.AMD16L8PALPAL16L8译码器--8X2764（8KX8）10-38088和80188存储器接口8088and80188(8-bit)MemoryInterfaceThememorysystems