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1、哈爾濱理下大學(xué)1=學(xué)碩上學(xué)位論文嵌入式USB主機接口的設(shè)計摘要USB接口具有使用方便、數(shù)據(jù)傳輸速率高和支持即插即用等特點,但由于USB接口協(xié)議復(fù)雜,使得USB的應(yīng)用開發(fā)非常困難。如何將USB設(shè)備應(yīng)用到嵌入式領(lǐng)域,實現(xiàn)USB的點對點通訊,成為目前USB研究領(lǐng)域的熱點。簡單來說,USB系統(tǒng)包括兩部分:USB主機與USB外設(shè)。USB外設(shè)的開發(fā)與基于PC機的USB主機技術(shù)已經(jīng)非常成熟,相對于在PC機上的豐富資源,嵌入式系統(tǒng)中有限的資源給基于嵌入式系統(tǒng)的USB主機系統(tǒng)開發(fā)帶來了很大難度。本文根據(jù)設(shè)計要求,首先分析了USBI.1協(xié)議,對U
2、SB的系統(tǒng)體系、數(shù)據(jù)通信模型、數(shù)據(jù)包格式、USB標(biāo)準(zhǔn)描述符進(jìn)行了深入剖析;其次,在分析USB大容量存儲設(shè)備(MassStorage)類規(guī)范的基礎(chǔ)上,建立了USB主機與MassStorage類設(shè)備之間的邏輯通信模型;嵌入式USB主機選用了Winbond公司的W78E59B芯片作為主CPU,使用Cypress公司的SL811HS芯片作為USB主機控制器芯片,構(gòu)建了USB主機系統(tǒng)。系統(tǒng)硬件方案設(shè)計具有成本低、功耗小、速度快等特點。在軟件上,系統(tǒng)完成了USB主機控制器驅(qū)動程序、核心驅(qū)動程序以及用戶軟件的設(shè)計。論文針對嵌入式USB主機的
3、設(shè)計作了分析和總結(jié),根據(jù)論文中提出的方法,實現(xiàn)了嵌入式USB主機系統(tǒng)的構(gòu)建,這對于開發(fā)嵌入式USB主機,使USB的應(yīng)用脫離PC機具有普遍意義。論文的最后對嵌入式USB主機的發(fā)展前景作了展望。關(guān)鍵詞USB主機;Massstorage類;SL811HS塞堡堡矍三奎蘭三蘭堡圭蘭堡堡苧DesignofTheEmbeddedUSBHostInterfaceAbstractUSBinterfacehasthecharacteristicsofconvenient—ilse,hJ【gh-speedandsupportinghot—plugg
4、inginPC.ThedevelopmentofUSBdevicesisdifficultbeeanseofthecomplexprotoc01.ThathowtoapplyUSBtoembeddedsystemandrealizecommunicationofpoint·-to·-pointbecomehotinthefieldofUSBresearchnOW.T11esimplifiedUSBsystemincludestwosubsystems:USBhostsystemandUSBslavesystem.Thedeve
5、lopmentofUSBslavesystemandtechnologyofUSBhostsystembasedonPChavebeenalreadymature,however,implementofUSBhostsystembasedonembeddedsystemencounteredmanydifficultiesbecauseoflimitcdreSOUrCeScomparedwiththeabundantresourcesonthePC.Accordingtothedesignrequestments,firstl
6、y,theUSBl.1specificationisanalyzed,inwhich,theUSBsystemarchitecture,datacommunicationmodel,datapacketformatandUSBstandarddescriptorhavebecomethekeypoint.Secondly,thelogicalcommunicationmodelbetweenhostanddeviceisestablishedonthebasisofanalyzingtheUSBdeviceMassStorag
7、eClassspecification.Thirdly,thattheEmbeddedUSBHostsystemselectsW79E58BandSL$11HStoactastheCPUandUSBHostinterfacechipseparatelyCOBStl'ncIstheHostsystem.Theprojectofthesystempossessesthevirtuesoflowcosts,lowpowerandhi咖speed,ete.Andfromthepointofthesoftware,thesystemin
8、tegratesUSBDriver,USBhostcontrollerdfivehandBSersoRware.ThepapermakesanalysisesandconclusionsonthedesignoftheembededHostsystem.Accordingto