USB基本術(shù)語及簡(jiǎn)單枚舉過程課件

USBHostSystemClientdriversoftwareUniversalBusDriver(USBD)HostControllerDriver(HCD)HostController(HC)USBDeviceSystemsoftwareHardwareHCIEhci/ohci/uhci/xhci1精選2021版課件TypeLowSpeed 1.1Mb/S (e.g.,USBMS/KB)FullSpeed 12Mb/S

(e.g.,USBflash)HighSpeed 480Mb/SSuperSpeed5Gb/SUSB1.1(UHCI/OHCI)USB2.0(EHCI)

ICH-7has4USB1.1Controllers&1USB2.0Controller,andsupports8USBports.

PCHhas2USB2.0Controllers&2USB2.0 USB3.0(XHCI)2精選2021版課件ICH7.port1port2port3port4port5port6port7port8UHCIControllerUHCIControllerUHCIControllerUHCIControllerEHCIController3精選2021版課件PCH.

TheHubsreplacethefunctionalityoftheUHCIcontrollersbyconvertinghigh-speedtrafficintolowandfull-speedtraffic.4精選2021版課件Terms.5精選2021版課件EndpointUSB通信最基本的形式是通過USB設(shè)備里一個(gè)叫Endpoint的東西，Endpoint是通信的發(fā)送或者接收點(diǎn)。Endpoint有確定的單一的方向，要么為in(Device->Host)，要么為out(Host->Device)。注意有一個(gè)例外：USB協(xié)議規(guī)定每個(gè)設(shè)備都必須有Endpoint0，它是雙向的，USB利用它來實(shí)現(xiàn)缺省的控制管道(ControlPipe)，從而控制設(shè)備。Endpoint共有四種類型：Control，Bulk，Interrupt，Isochronous.6精選2021版課件PipeAUSBpipeisanassociationbetweenanendpointonadeviceandsoftwareonthehost.

Pipesrepresentthe

abilitytomovedatabetweensoftwareonthehostviaamemorybufferandanendpointonadevice.7精選2021版課件Frame&MicroFrameUSBestablishesa1millisecondtimebasecalledaframeonafull-/low-speedbusanda125μstimebasecalledamicroframeonahigh-speedbus.A(micro)framecancontainseveraltransactions.8精選2021版課件TransferTypes對(duì)應(yīng)于四種不同的Endpoint同樣有四種不同的傳輸方式：控制傳輸(ControlTransfer),中斷傳輸(InterruptTransfer),批量傳輸(BulkTransfer),等時(shí)傳輸(IsochronousTransfer).控制傳輸(ControlTransfer)通常用于配置設(shè)備，獲取設(shè)備信息，發(fā)送命令到設(shè)備，或者獲取設(shè)備的狀態(tài)報(bào)告等，總之就是用來傳送控制信息的.中斷傳輸(InterruptTransfer)用來以一個(gè)固定的速率傳送少量的數(shù)據(jù)，USB鍵盤和USB鼠標(biāo)使用的就是這種方式.9精選2021版課件批量傳輸(BulkTransfer)用來傳輸大量的數(shù)據(jù)，確保沒有數(shù)據(jù)丟失，并不保證在特定的時(shí)間內(nèi)完成。U盤使用的就是批量傳輸，咱們用它備份數(shù)據(jù)時(shí)需要確保數(shù)據(jù)不能丟，而且也不能指望它能在一個(gè)固定的比較快的時(shí)間內(nèi)拷貝完.massstoragedevice（U盤）.等時(shí)傳輸(IsochronousTransfer)同樣用來傳輸大量的數(shù)據(jù)，但并不保證數(shù)據(jù)是否到達(dá)，以穩(wěn)定的速率發(fā)送和接收實(shí)時(shí)的信息，對(duì)傳送延遲非常敏感。常用于音頻和視頻一類的設(shè)備，這類設(shè)備期望能夠有個(gè)比較穩(wěn)定的數(shù)據(jù)流.camera.Detail:USB2.0SPEC5.5&5.6&5.7&5.8Difference:Bandwidth&Priority&errorretry10精選2021版課件ConfigurationConfiguration:AUSBdevicemustbeconfiguredbeforeitsfunction(s)maybeused.Interface:

Withinasingleconfiguration,adevicemaysupportmultipleinterfaces.Aninterfaceisarelatedsetofendpointsthatpresentasinglefeatureorfunctionofthedevicetothehost.Alternatesettings:aninterfacewithinaconfigurationmayhavealternatesettingsthatredefinethenumberorcharacteristicsoftheassociatedendpoints.Endpoint:

DatamaybetransferredbetweenaUSBdeviceendpointandthehostinoneoffourways.Anendpointnumbermaybeusedfordifferenttypesofdatatransfersindifferentalternatesettings.Chooseaproperlyfunction/featuretoUSBdevice.USB2.0spec9.2.311精選2021版課件USBDeviceStates

&Enumeration12精選2021版課件13精選2021版課件Attach&Powered&Defaultstate由portstatusregister來控制和體現(xiàn)。

Address&configuredstate由USBstandardcommand來配置。

Note:differentfromgenericHUB.14精選2021版課件SuspendAlldevicebeginthetransitiontotheSuspendstateaftertheyseeaconstantIdlestateontheirupstreamfacingbuslinesformorethan3.0ms.Globalsuspend:theentirebusisplacedintheSuspendstate.Selectivesuspend:

SegmentsofthebuscanbeselectivelysuspendedbysendingthecommandSetPortFeature(PORT_SUSPEND)tothehubporttowhichthatsegmentisattached.15精選2021版課件PoweredstateThehubtowhichtheUSBdeviceisnowattachedinformsthehostoftheeventviaareplyonitsstatuschangepipe.Ahubportmustbepoweredinordertodetectportstatuschanges,includingattachanddetach.thehostthenwaitsforatleast100mstoallowcompletionofaninsertionprocessandforpoweratthedevicetobecomestable.16精選2021版課件DefaultstateWhentheresetsignalisreleased,theporthasbeen

enabled.Afterreceivingareset,thedeviceisthenaddressableatthe

defaultaddress.Whentheresetprocessiscomplete,theUSBdeviceisoperatingatthecorrectspeed.low-andfull-speedisdeterminedbythedeviceterminationresistors.Adevicecapableofhigh-speedoperationmustresetsuccessfullyatfull-speedwheninanelectricalenvironmentthatisoperatingatfull-speed.17精選2021版課件AddressstateAllUSBdevicesareaccessedbyaUSBaddress.AllUSBdevicesmustsupportendpointzerotowhichtheUSBdevice’sUSBcontrolpipewillbeattached.BeforetheUSBdevicereceivesauniqueaddress,itsDefaultControlPipeisstillaccessibleviathedefaultaddress.ThehostassignsauniqueaddresstotheUSBdevice,movingthedevicetotheAddressstate.SetAddresscommandisastandardUSBcommand.HowtosendastandardUSBcommandunderXHCI/EHCI/UHCI/OHCIenvironment.

18精選2021版課件ConfiguredstateGet

ConfigurationdescriptorbygetConfigurationcommand.thehostassignsaconfigurationvaluetothedevice.ThedeviceisnowintheConfiguredstateandalloftheendpointsinthisconfigurationhavetakenontheirdescribedcharacteristics.SetConfigurationcommandisastandardUSBcommand.19精選2021版課件SetInterfaceWithinasingleconfiguration,adevicemaysupportmultipleinterfaces.Aninterfaceisarelatedsetofendpointsthatpresentasinglefeatureorfunctionofthedevicetothehost.SomeUSBdeviceshaveconfigurationswithinterfacesthathavemutuallyexclusivesettings.Thisrequestallowsthehosttoselectthedesiredalternatesetting.SetinterfacecommandisastandardUSBcommand.20精選2021版課件USBDeviceRequests

AllUSBdevicesrespondtorequestsfromthehostonthedevice’sDefaultControlPipe.21精選2021版課件StandardDeviceRequests

22精選2021版課件DescriptorsDevicedescriptor:generalinformationaboutaUSBdevice.AUSBdevicehasonlyonedevicedescriptor.DeviceDescriptor:bLength:18bDescriptorType:1DeviceDescriptorbcdUSB:512bDeviceClass:0xffmassStor\HID\HubbDeviceSubClass:0xffbDeviceProtocol:0xffbMaxPacketSize0:0x40Maxpacketsizeforendpoint0.idVendor:0x4b4VendorID.idProduct:0x8613ProductID.bcdDevice:0xa001FWversion.iManufacturer:0x0iProduct:0x0iSerialNumber:0x0bNumConfigurations:0x1Numberofconfigurations.Example:23精選2021版課件DescriptorsConfigu