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Developing USB PC Peripherals

1. 64 Logical Connections svrvrovnrvnne 10 LOW Speed 8 M Mbps arrena e 103 IG VA EE 37 MOSS EE 38 Memory Organization 38 Memphis Operating System 89 MFC DEL i jevnt vei 80 Microsoft Developer Network OMSIDN inaani 34 Microsoft Developer Studio 79 Microsoft Visual CC 34 Modem 103 Most Significant Bit MSB rnanan 16 103 Multitasking 62 103 N NACGR coh elects AANE AR 17 103 NAK Handshake 20 Non Page Mode 40 NRZI Encoding Decoding 44 103 NT Executve 63 103 NT Executive s I O system 66 NI Kerel anera 63 O EE 103 Object Manager 65 103 Object Model 63 67 OLE ControlWizard eonorvrernrr 80 Open Host Controller Interface OHED issues 30 61 Eben A 28 104 OUT Backen 52 OUT Token 11 17 20 23 53 P ET 104 Packet Format 15 Packet H keeft adniacndai 104 Page Mode 40 PC Legacy Class 60 PCL agence 104 Physical Device oonoronorvnnoneeenr 104 Physical Interface Class 60 FID EE 15 PIP 2h cites ee ee 10 104 NEE 104 Plug and Play 3 21 61 89 104 Si E 97 Polling i 4andadedaadaadade 104 Port Enable and Reser 22 POTS EE 104 Power Class 60 175 Power Supp 15 Preamble PRE Packet 18 Printer Class PROCESS ege naanin Product Identification Information idProduct ee 72 Programmable Counter Array PCA sea ee 37 43 Protocol Zeeche kjent 18 105 Pull Up Resistor sseeeeeee 14 Pulse
2. Chapter 8 Firmware WDM Driver and Application Software Chepter g Next Step Figure 1 1 Chapter Layout 1 3 References These references will appear several times throughout the book They will be designated by their number in subscript next to the referral For example you ll see something like this un 1 Compaq Digital Equipment Corporation IBM PC Company Intel Microsoft NEC and Northern Telecom USB Specification 1 0 revision 1 0 Jan 19 1996 http www usb org What Will This Book Do For You 2 To join the USB Implementers Forum contact USB IMPLEMENTERS FORUM JF2 51 2111 NE 25th Avenue Hillsboro OR 97124 For more information see http www usb org 3 Sx930Ax 8x930Hx USB Microcontroller User s Manual order no 272949 001 September 1996 It can be ordered from Intel Corporation Literature Sales P O Box 7641 Mt Prospect IL 60056 7641 Or call 1 800 879 4683 or http www intel com design usb manuals 4 8x93QAx USB Microcontroller Datasheet order no 272917 003 February 1997 and the 8x930Ax Specification Update order no 272940 available at http www intel com design usb 5 Helen Custer Inside Windows NT Microsoft Press a Division of Microsoft Corporation 1993 6 Dave Hamilton and Mickey Williams Programming Windows NT 4 Sams Publishing 1996 7 Ori Gurewich and Nathan Gurewich Teach Yourself Visual C 4 in 21 Days Sams Publishing 1996 1 4 Feedback to
3. issue a synchronous request see notes above KelnitializeEvent amp event NotificationEvent FALSE irp IoBuildDeviceloControlRequest IOCTL INTERNAL USB SUBMIT URB deviceExtension gt PhysicalDeviceObject NULL 0 NULL 0 TRUE INTERNAL amp event amp ioStatus Prepare for calling the USB driver stack nextStack loGetNextIrpStackLocation irp ASSERT nextStack NULL Set up the URB ptr to pass to the USB driver stack nextStack gt Parameters Others Argumentl Urb Call the USB class driver to perform the operation If the returned status is PENDING wait for the request to complete ntStatus IoCallDriver deviceExtension gt PhysicalDeviceObject irp if ntStatus STATUS PENDING status KeWaitForSingleObject amp event Suspended KernelMode FALSE NULL else ioStatus Status ntStatus 143 A WDM Driver Code Example II USBD maps the Error code for us USBD uses Error codes in its URB A structure that are more insightful into USB behavior To allow more insight into the specific USB Error that occurred your driver may wish to examine the URB s status code Urb gt UrbHeader Status as well ntStatus ioStatus Status return ntStatus We NTSTATUS Test_ConfigureDevice IN PDEVICE OBJECT DeviceObject Configures the USB device via USB specific device requests and interaction with the USB software subsystem DeviceObject pointer to t
4. CRC Figure 2 10 A USB SOF packet It consists of a PID indicating the SOF packet followed by an 11 bit frame number 2 8 3 Data Packets In USB the host performs the management of the bus and devices respond to requests from the host If the host requests information from a device it will send an IN token addressed to that device endpoint and the device will response with a USB data packet The format of the data packet is as shown in Figure 2 11 with the PID indicating DATAO or DATAI SYNC PID DATA CRG Figure 2 11 A USB data packet If the transfer type of this particular endpoint is bulk control or interrupt the host will response with an acknowledgment when it receives the data without error If the transfer type is isochronous no handshake packet will be sent The host will send an OUT token followed by a data packet if it wishes to transfer data to the device 2 8 4 Handshake Packets The handshake packets consist of only a PID as shown in Figure 2 12 They are used to report ACK NACK or STALL as indicated by the PID for transactions that require handshakes SYNE PD Figure 2 12 A USB handshake packet 17 USB Protocol by Transfer Types 2 8 5 Special Packets The special preamble PRE packet is sent by the host when it wishes to communicate to low speed devices The host will send this PRE packet first before sending low speed 1 5 Mbps packets to communicate with low speed devices 2 9 USB
5. Cleans up certain elements of the device object This is called when the device is being removed from the system DeviceObject pointer to DeviceObject Return Value None 141 A WDM Driver Code Example PDEVTCE_EXTENSION deviceExtension UNICODE STRING deviceLinkUnicodeString deviceExtension DeviceObject gt DeviceExtension if deviceExtension gt NeedCleanup deviceExtension gt NeedCleanup FALSE RtlInitUnicodeString amp deviceLinkUnicodeString deviceExtension gt DeviceLinkNameBuffer IoDeleteSymbolicLink amp deviceLinkUnicodeString NTSTATUS Test CallUSBD IN PDEVICE OBJECT DeviceObject IN PURB Urb Passes a Usb Request Block URB to the USB class driver USBD Note that we create our own IRP here and use it to send the request to the USB software subsystem This means that this Routine is essentially independent of the IRP that caused this driver to be called in the first place The IRP for this transfer is created used and then destroyed in this Routine DeviceObject pointer to the device object for this instance of a Test Device Urb pointer to Urb request block Return Value STATUS SUCCESS if successful STATUS UNSUCCESSFUL otherwise Wi NTSTATUS ntStatus status STATUS SUCCESS PDEVICE EXTENSION deviceExtension PIRP irp 142 Appendices KEVENT event IO STATUS BLOCK ioStatus PIO STACK LOCATION nextStack deviceExtension DeviceObject gt DeviceExtension
6. Transmit ISR wae ee OE SER Figure 5 1 USB device program flow 5 3 1 Initialization After chip reset the device will execute its initialization routine to initialize the USB modules peripherals or user defined flags The USB Specification allows a device to have multiple interfaces For example you can have endpoint I configured for bulk transfer endpoint 2 as interrupt for interface one and for interface two you can have endpoint 1 configured as an isochronous endpoint and endpoint 2 as an interrupt endpoint Depending on which interface we choose endpoint 1 handles either bulk or isochronous transfer To keep this operating model simple let s use only one interface for the USB device You will need to prepare your device to perform the various transfer types that are required Endpoint pair 0 is required to handle control transfer as dictated by the USB Specification For Endpoint pairs 1 2 3 you can choose to configure them to be control bulk interrupt or isochronous endpoints as required by the device To configure an endpoint pair to handle control transfer it is required to set the control endpoint CTLEP receive endpoint enable RXEPEN and the transmit endpoint enable TXEPEN bits of the EPCON register for that particular endpoint To configure a transmit endpoint for isochronous transfer set the transmit isochronous data TXISO bit in the TXCON register for that 51 The 8x930Ax Operating Model particular
7. urb if pvOutputBuffer UsbBuildGetDescriptorRequest urb USHORT sizeof struct URB CONTROL DESCRIPTOR REQUEST USB CONFIGURATION DESCRIPTOR TYPE descriptor type 0 index 0 Nanguage ID pvOutputBuffer transfer buffer NULL Y MDL ulLength buffer length NULL Nink ntStatus Test CallUSBD DeviceObject urb else ntStatus STATUS_NO_MEMORY 2 J length urb gt UrbControlDescriptorRequest Transfer BufferLength Ex Free Pool urb jelse ntStatus STATUS NO MEMORY return length The management of the IRPs and URBs thread scheduling is performed by the Windows NT operating system Figure 6 6 depicts the high level program flow of this operation 71 Loading the WDM Drivers user thread application program er EE kernel mode mm system services driver I I O manager manages the IRPs WDM driver layering Figure 6 6 An I O request example 6 6 Loading the WDM Drivers When we plug in a USB device to the USB host PC the host will enumerate the device Among other things the device descriptor information will be gathered by the host The Vendor identification information idVendor assigned by the USB IF Product identification information idProduct assigned by the device manufacturer and Device release number bcdDevice assigned by the device manufacturer of this descriptor refer to Chapter 9 6 1 of the USB specification will then be u
8. 1 e pipes in USB software terminology and User Mode file names You are free to use any convention you wish to create these links although the above convention offers a way to identify resources on a device by familiar file and directory structure nomenclature DeviceObject pointer to the device object for this instance of the Test device Return Value NT status ZS NTSTATUS ntStatus Irp gt IoStatus Status STATUS SUCCESS Irp gt IoStatus Information 0 Create all the symbolic links here ntStatus Irp gt IoStatus Status loCompleteRequest Irp IO NO INCREMENT return ntStatus NTSTATUS Test_Close IN PDEVICE OBJECT DeviceObject IN PIRP Irp p Entry point for CloseHandle calls from user mode apps to close handles they have opened 152 Appendices DeviceObject pointer to the device object for this instance of the Test device Irp pointer to an irp Return Value NT status Si NTSTATUS ntStatus STATUSJSUCCESS return ntStatus We NTSTATUS Test_ProcessIOCTL IN PDEVICE OBJECT DeviceObject IN PIRP Im Vo This is where all the DeviceloControl codes are handled You can expand and add more code here to handle IOCTLARP codes that are specific to your device driver DeviceObject pointer to the device object for this instance of the test device Return Value NT status PIO STACK LOCATION irpStack PVOID ioBuffer ULONG inputBufferLength ULONG outputBuff
9. Error Checking snernrornvervvrnvrrnne 17 Evaluation Km 35 101 External Memory Interface 40 F FIFOs grennra ena una 44 File Handlen 67 86 101 Firmware Overhead 49 FLASH memor 49 eame REENEN 7 101 Frame Timer tacked 42 BUILT Speed VE 8 Full duplex orroonroonororoonrnenernnne 102 me ege Su Ae Sethe el 9 Function Address Feld 16 Function linterface Unit FIU 44 FUNCTIONS HL ya Seieren 21 G GET DESCRIPTOR 19 22 23 GND een iene tees 14 15 H TVA EE 63 102 Handshake Packet 17 102 Hardware Abstraction Layer HAD iss apene 63 102 Hardware Watchdog Timer 43 HID human input device 59 HO stisgsrsseienatnies 9 28 102 174 Host Controller Driver HOD iser deeg 30 61 Host Controller Driver Interface 30 Hub stenken 9 102 Hub Class 60 Human Interface Class 60 I I O Manager 66 102 I O Request Packet IRP 66 IEEE 1394 Frewre 61 Image Class rnrrnorororvrorrrnernrvveen 60 IN Raeren EE 52 IN Token 11 17 23 52 58 In Circuit Emulator ICE 33 Initialization 51 Integral Subsvstems 64 Interrupt Service Routine ISR fe Maes 41 52 Interrupt System ee 41 Interrupt Transfer 12 21 102 IR 66 102 Isochronous Transfer 12 20 102 K KDPS redet 103 Kernel Mode 62 64 103 L Layered Model 62 Least Significant Bit LSB 16 Little Endian seoororororronornrenne 103 Local Procedure Call LPC
10. Save it here ICall Ch9Decode proceed to Process it pop DPX Restore DPX ljmp ReturnProcessOutToken NeedMoreData CheckCommand2 112 Appendices ReturnProcessOutToken Ret SetupReceived device braches here when a setup token received SetupReceived mov A RXCNTO Get the no of bytes clr CY subb A 8 8 is length of all setup packets INZ ReturnSetup If less than 8 bytes reed Return clr EDOVW mov COMMAND BUFFER RXDATO i bmRequestType mov COMMAND BUFFER 1 RXDATO bRequest mov COMMAND BUFFER 3 RXDATO wValue LSB mov COMMAND BUFFER 2 RXDATO wValue MSB mov COMMAND BUFFER 5 RXDATO wlndex LSB mov COMMAND BUFFER 4 RXDATO wlndex MSB mov COMMAND BUFFER 7 RXDATO wLength LSB mov COMMAND BUFFER 6 RXDATO wLength MSB push DPX Processing the jump table will corrupt DPX Save it here setb RXFFRC 33 moved here for OHCI systems clr RXSETUP si ditto 1Call ProcessSetup pop DPX Restore DPX ReturnSetup Ret Process Setup decode the setup packet received ProcessSetup 113 Firmware Code Example For Intel 8x930Ax USB Microcontroller mov ControlBuffBytesLeft 00h mov ControlBuffBytesLeft 1 00h mov A bmRequestType jb ACC 7 SetupGetCommand SetupSetCommand mov SetupRxFlag ADATA PHASE Advance flag to next state mov SetupTxFlag HSTATUS PHASE Now check to see if this is a control write with a data stage mov A wLength orl A wLength 1 jz Ch9Decode If
11. Universal Serial Bus devices to be able to receive and send packets The host based software responsible for managing the interactions between the host and the attached Universal Serial Bus devices The direction of data flow towards the host Universal Serial Bus Universal Serial Bus Driver The host resident software entity responsible for providing common services to clients that are manipulating one or more functions on one or more Host Controllers The non privileged processor mode in which application code runs A thread running in user mode can gain access to the system only by calling system services 106 Appendices 11 Appendices 11 1 Firmware Code Example For Intel 8x930Ax USB Microcontroller Usb enum ASM Firmware for the 8x930Ax Ax2 Ax3 and Ax4 to perform USB enumeration Itis to be programmed into a 32 Kbyte EPROM of the Evaluation kit to be used as a USB Test Device srev 1 0 3 Mar 97 INCLUDE 8x930Ax h FIFO SIZE equ 008h GET_COMMAND equ 080h SETUP PHASE equ 000h DATA PHASE equ 001h STATUS PHASE equ 002h EPO MAX PACKET SIZE equ 08h NULL DATA PACKET equ 000h org Off 7ff8H db 0D6h congifuration bytes Binary Mode Paged Mode etc db OEFh org 00 4000H if use PLC and RISM org Off 0000H ljmp main org 00 4043H org Off 0043H ljmp SOF ISR org 00 404BH 107 Firmware Code Example For Intel 8x930Ax USB Microcontroller org Off 004BH ljmp FUNCTION ISR org 00
12. handshake or special packet These four types of packets are subdivided into various identifiers differentiated by PID and PID3 Packet Type PID Name E E PID4 PiDg 01 01 Handshake Handshake Handshake Note that bits in USB are sent out least significant bit LSB first followed by next LSB and completed with the most significant bit MSB last For all the diagrams in this chapter packets are displayed in a left to right reading mode showing the order they would be moving across the bus 2 8 1 3 ADDR The 7 bit function address ADDR field specifies which device the packet is intended for The host assigns a unique address to each device during USB enumeration process when it is first attached to the bus 2 8 1 4 ENDP The 4 bit endpoint ENDP further specifies which tiny pipe of the device the packet is intended for For example a device has endpoint 0 and endpoint 1 configured the host can choose to communicate to endpoint 0 of this device at this instant ignoring endpoint 1 Step 1 Understand the USB Specification 2 8 1 5 CRC Cyclic Redundancy Checks CRCs provide error checking for the non PID fields of the USB packet The FID is not protected by this CRC as it has self error checking as shown in Figure 2 9 above 2 8 2 Start of Frame Packets Start of Frame SOF packets as shown in Figure 2 10 are broadcast by the host once every 1 00 ms 0 05 SYNC PID FrameNumber
13. malloc sizeof Usb_Device_Descriptor 64 Perform the Get Descriptor IRP DeviceloControl hDrvrHnd IRP TEST GETTWO pvBuffer sizeof Usb_Device_Descriptor pvBuffer sizeof Usb_Device_Descriptor amp dwStatus NULL free pvBuffer AfxMessageBox completed Set Command One SH void CUsbappA pp OnSetTwo not implemented yet 171 An Application Software Code Example AfxMessageBox This function has not been implemented BOOL CUsbappApp InitApplication TODO Add your specialized code here and or call the base class return CWinApp InitA pplication void CUsbappApp OnInitTest if hDrvrHnd INVALID HANDLE VALUE MessageBox NULL Failed to Locate USB Tset Devices Error MB OK else if pTestDesc NULL free pTestDesc pTestDesc malloc sizeof USBTESTCTRLDESC memset pTestDesc 0 sizeof USBTESTCTRLDESC 172 12 Index 8 8x930Ax USB Evaluation Kit 32 8x930Ax USB Microcontroller 37 8x930Ax USB Module 44 SXCSTEX EE 38 A Te EE 17 99 ACK handshake 19 20 23 ADDRi ENET 16 Address OU 22 ALE Address Latch enable 40 Apbuilder oseere 99 GEET RE Bes 99 Application Specific Firmware 49 App Wizard sser 35 79 Audio Class 60 B Danduwidtb eeeeeee 7 99 BigEndian SARL 99 EE 99 Bit Stftg 99 er 99 Bulk Transfer 12 20 99 Bus Eoumeraton 99 Bus Interface Layer 28 ENTENTE
14. push EPINDEX mov EPINDEX 01 mov TXDAT 20h mov TXCNT 01h pop EPINDEX orl EPCONQ 0COh Stall Endpoint ret StandardSetlnterfaceCommand StandardGetInterfaceCommand StandardSetOtherCommand StandardGetOtherCommand ret InReceived device branches here when IN token received InReceived anl FIS EPO TX CLR clear the interrupt bit ljmp CheckInStatusPhase CheckInStatusPhase mov A SetupTxFlag read state variable cjne A STATUS_PHASE SendDataBack Should this be the end to a setup sequence StatusPhaseDone ICall CompleteSetCommand mov SetupTxFlag SETUP_PHASE Set state var to expect setup mov SetupRxFlag ASETUP PHASE ljmp ReturnProcessIn SendDataBack cjne A HDATA PHASE ReturnProcessIn 1Call LoadControlTXFifo ReturnProcessIn Ret 122 Appendices CompleteSetCommand CompleteSetCommand mov A bRequest If this was not a Std Set command then return cjne A SET_ ADDRESS CheckNextCommand SET ADDRESS DoSetFuncAddress mov FADDR wValue 1 Set to new address ljmp ReturnCompleteSet CheckNextCommand ReturnCompleteSet ret SetUpControlWriteStatusStage SetUpControlWriteStatusStage mov TXCNTO 00 Setup Null Packet setb TXOEO Enable data transmit Ret LoadControlTXFifo LoadControlTXFifo push RO push DPX mov DPXL ControlBuffLocation Get location of data to send mov DPH ControlBuffLocation 1 mov DPL ControlBuffLocation 2 mov A
15. user flags and the stack pointer It defines two important user flags SetupRxFlag and SetupTxFlag to keep track of the different stages of the control transfer either the setup data or status stage After the initialization the code goes into an idle loop Note that port 1 of the 8x930Ax is used to control the LEDs of the Evaluation Board comes with the Evaluation Kit In this loop you can add some application specific firmware for your device Or alternatively you can design your application firmware to be interrupt driven Consider a joystick for example when you press a fire button the hardware can be designed to cause an external interrupt to the microcontroller The firmware will then branch to execute the ISR of this external interrupt and send appropriate USB packets to the host to inform it of the status change of the fire button Back to the USB ENUM ASM example after initialization the firmware will be looping in the idle loop waiting for an interrupt as shown in Figure 5 5 When a USB interrupt arrives a FUNCTION_ISR ISR will be executed as shown in Figure 5 6 This ISR will first check the source of the interrupt and if the source is caused by transmit endpoint 0 it will branch to an InReceived subroutine If the interrupt is caused by receive endpoint 0 it branches to a SetupOutToken subroutine In the SetupOutToken subroutine it needs to check the data received for whether the token received was a SETUP or
16. 23 Bus Topology cccesceeseeeeeeeees 8 Byte restos maine mae 99 C ablenne ees 13 ClasswWizard 80 Client tts Set eee 30 60 99 Client Layer 30 60 Client Server Model 62 100 173 COM pont 100 Common Class 60 Communications Class 60 CONNECOTS sired sii 13 SETTES see 13 Series B E ett Leide Sege 13 Control Transfer 11 18 100 Lei CC 17 100 CTD iin an eae 100 Cyclic Redundancy Checks CRES ET 17 D te des e A Ae un 2 14 22 27 44 48 D A converter mesinin nenn 43 I Da Ee 14 22 27 44 48 Data Packets oeie tet aes 17 Default Address 11 22 100 Default Pipe ooeec 100 Development Environment Device Side rrnrrrrronrrorornnrerrenere 31 Host Sid ss teceasakaadadas 34 RE 9 100 Device Address 10 Device Class Driver 50 59 Device Class Specification 59 Device Classes rrrrornrrorornrrerernerere 60 Device Firmware rorrrnrrorornvrerrenere 49 Device Interface Layer 29 Device Object seese 100 Device release number bcdDevice KI Bi EEN EE EE E Downstream Downstream Devices IR EE MEIER E Index Index Driver Object 86 101 DWORD edu be ete 101 E ENDP red E onde deed 16 Endpoint Cranes 10 101 Endpoint0 oseese 22 Endpoint Address 101 Enumeration Code 56 Enumeration Steps s es 21 Environment Subsystem 101 Environment Subsystems 64 BOP 2 tt tee 101 EPROM nereo 39 49 91 101
17. 4080H org Off 0080H Main mam mov SP 00h mov SPH 01h Set the stack to start 00 0500h mov DPXL 0ffh Set DPXL to point at the FLASH device to access constants Init_ Variables mov RO 00h mov Beatl RO mov Beatl 1 RO zeroing counter mov SetupRxFlag RO SetupSeq is set to mov SetupTxFlag RO Setup PHASE mov ControlBuffLocation RO Zeroing pointer mov ControlBuffLocation 1 RO mov ControlBuffLocation 2 RO mov ControlBuffBytesLeft RO zeroing counter mov WRO 0 zeroing counter mov WR2 WRO Init Usb configure endpoint 0 EPO mov EPINDEX 00 select EPO nop nop mov EPCON 3Fh enables as control endpoint single packet mode receive enabled and transmit enabled orl FIE 03h enable EPO TX amp RX interrupts setb TEN1 1 enable interrupts setb SOFIE enable SOF interrupt 108 Appendices setb IEN1 0 enable SOF ISR setb EA enable glabal interrupts mov pl 00H Pl is the LED indicator in eval kit CLR LC increase the CPU speed from 3 MHz to 12 MHz ljmp Idle loop Idel loop device looping here awating interrupts Idle loop nop nop can implement user applications here nop LedBeat mov WRO Beatl inc WRO 1 mov Beatl WRO cmp WRO 7FFFh jl ClrBit setb P1 0 ljmp Idle_loop ClrBit clr P1 0 ljmp Idle_loop FUNCTION ISR device jumps here when a receive done or transmit done interrupt occurs FUNCTION ISR push ACC push B push
18. 9055 Europe 49 81 31 70610 Korea 82 2 783 7835 Japan 81 334050511 36 numega com keil com plcorp com systemsoft com ptltd com megatrends com nohau com isystem com Step 3 Developing The Device Hardware 4 Step 3 Developing The Device Hardware As mentioned in the previous chapter the Intel 8x930Ax USB microcontroller will be the reference base for the USB device we will build This chapter examines the architecture of the 8x930Ax microcontroller its USB module and how we can use it in our device 4 1 Overview of the 8x930Ax USB Microcontroller The 8x930Ax microcontroller is the world s first USB Spec 1 0 compliant microcontroller commercially available It is meant to be used to develop a hubless USB device A detailed description of the 8x930Ax microcontroller can be found in the 8x930Ax 8x930Hx USB Microcontroller User s Manual and datasheet This section will summarize the important features of the microcontroller The 8x930Ax is based on a MCS 251 core and has various on chip peripherals an industrial standard MCS 51 Universal Asynchronous Receiver and Transmitter UART 5 modules of programmable counter arrays PCA 3 general purpose timers counters a hardware watchdog timer and a USB module It is available in various ROM and RAM sizes as shown in Figure 4 1 ROM size bytes RAM size bytes EE Pee 80930AD CK SO O 33030AD B3930AE Figure 4 1 8x930Ax product options 4 1
19. A method of storing data that places the most significant byte of multiple byte values at lower storage addresses A binary unit of information used in computers A bit has the choice of two possibilities typically represented by a logical one 1 or zero 0 Insertion of a 0 bit into a data stream of V to cause an electrical transition on the data wires to allow the locking of PLL circuitry Bit per second It is used as a unit of measurement for data transmission rates One of four USB transfer types It represents a non periodic large bursty data transmission typically used for a transfer that can use any available bandwidth and that can also be delayed until bandwidth is available A process of communication between a USB host and a USB device when the device is first plugged into the bus It is used for identifying the USB devices A data element that is eight bits in size Software resident on USB host that interacts with host software to arrange data transfer between a function and a host The client is often the data provider or consumer of the transferred data 99 Glossary Client Server Model COM port Control transfer CTI Default address Default pipe Device Device Object DLL An application or operating system model where the system is divided into processes server each of which provides a set of specialized services to other processes clients Communications port An eight bit
20. Code Modulation PCM 12 Pulse Width Modulation PWM 43 R Receive Routine sser 53 References navet 4 Remote Wakeup nsec 27 Request ieii neii 105 Reset i raaa aha e a 27 RESUME ee 27 AE HE 41 KEE 33 RCOMleeg EEN 39 Root H b maeaea uniin 9 105 Root Port 105 S ES E O eege 105 SEO single ended zer 27 Serial Bus Interface Engine SIE KEE 44 Serial Interface Engine SIE 61 Serial Port UART seee 43 Series Reatstorg 14 SET ADDRESS 22 23 27 58 SET CONFIGURATION 20 22 SETUP Backen 52 Setup Routine sornnernvrnvvrnnrrnn 54 SETUP Token eee 19 52 58 SFRS eiiiai 46 105 Single Step Transaction Debugger SSTIDI peer 33 NG EE 15 17 105 SOF interrupt 42 SOF Backen 19 24 42 Index Index SOF Routine KRIER Special Function Register s SERS gt tee seia 46 Special Backes 18 STAGE EE 18 105 STALL tenesta anien 17 STALL Handebake ee 20 Start of Frame SOF Backes 17 Storage Class rrrnrrnrrrrnrrvnrnrernnr 60 Suspend nccesser 27 Symmetric Multiprocessing 64 SYNG eee 15 SBvnchrontzapon 105 r Thread Scheduling 63 106 Tiered Star Topology rrrrrrerrrr 8 Time Division Multiplexing CHEM 7 105 RI fala peated 106 Timer Counter Units 0 43 Token Packets 0000000000000 15 106 Transacton 106 Transfer Type 11 106 Transmit Routine 52 TRAP Interrupt 42 U Un Enumerated Stage 0 52 176 Universal Asynchron
21. EPINDEX CheckInterruptSource F EPO RX 109 Firmware Code Example For Intel 8x930Ax USB Microcontroller jnb FRXDO F EPO TX mov EPINDEX 00 Call SetupOutToken 930Ax has received a packet from host PC F EPO TX jnb FTXDO F EP1 TX mov EPINDEX 00 ICall InReceived 930 Ax has sent a packet to host PC F EPI TX EXIT FUNCTION ISR pop EPINDEX pop B pop ACC reti SOF ISR at every Ims do nothing here for our example SOF ISR clr ASOF cpl p1 3 complement p1 3 as indication reti SetupOutToken check whether a Setup or an OUT token is received SetupOutToken anl SBI EPO RX CLR Clear the interrupt bit ljmp ProcCommand ProcCommand mov A RXSTAT jnb ACC 6 CheckOutStatusPhase check if this is a setup packet 110 Appendices mov A TXFLG anl A 0C0h jZ NoEPOError NoEP0Error ICall SetupReceived 33 moved setb RXFFRC Update receive FIFO state 33 moved clr RXSETUP ljmp ReturnProcessOutToken CheckOutStatusPhase mov A SetupRxFlag cjne A STATUS_PHASE OutReceived the status phase of a GET command setb RXFFRC Update receive FIFO state setb TXCLR Flush the Transmit FIFOS in case anull packet is still left mov A SETUP_PHASE Update the flag mov SetupRxFlag A mov SetupTxFlag A ljmp ReturnProcessOutToken control Write Data Stage If this is a control write command with a datastage then this Routine will be called on all data stages of the co
22. Figure 8 6 USB transactions as captured by a CATC bus analyzer The application software WDM driver and firmware in this example only perform some very simple and basic USB functions In this example only endpoint 0 is enabled and used to perform USB enumeration and various control functions Nevertheless it provides a simple USB example allowing you a good basic understanding of the operation of the USB host WDM driver and the USB device To get other code examples for application software WDM drivers or device firmware performing various USB transfer types you can contact 94 USB Application Software WDM Driver and Firmware Examples the Intel web site at http www intel com design usb swsup USB code examples can also be found in the Microsoft USB DDK package 8 3 Deleting Driver and ID Information from the Host When you re done with the example you might want to delete the product information and the device driver from the host PC To do this you ll need to delete the product information from the registry of the host PC First activate the registers editor regedit exe located in your windows directory Using the regedit locate the registry information of the device which is in the HKEY LOCAL MACHINE Enum USB directory as shown in Figure 8 7 Delete this production information by selecting the product and vendor identification information then press the delete key CH HKEY_CLASSES_AOOT 83 HKEY DURRENT USER
23. Logical connections from host to USB devices Logical Device 2 5 USB Pipe Concept Device Address and Endpoint USB communication can be viewed using a pipe concept as shown in Figure 2 3 BIG USB PIPE 12 Mbps HOST PC small pipe to each USB device up to 127 devices using device address tiny pipes endpoints Figure 2 3 Concept of the USB pipes and endpoints It consists of a big pipe 12 Mbps and up to 127 small pipes Each of the small pipes connects to a USB device There are 7 address bits in the USB token more details in section USB Packet Formats which can Step 1 Understand the USB Specification address up to 128 devices However address 000 OOOOB called the USB default address is used for all devices when they are first attached Thus USB can support up to 127 devices Each of the small pipes connected to a USB device can be further divided into smaller pipes which we refer to as tiny pipes as shown in Figure 2 3 There can be up to 16 pairs of these tiny pipes from a single small pipe This is because there are 4 endpoint bits in a USB token and the token can be identified as IN or OUT tokens After a device receives an IN token it will transmit data to the host and if it receives an OUT token it will anticipate data from the host The endpoints are associated with tiny pipes here to illustrate the USB pipes concept clearly to readers These endpoints or tiny pipes are th
24. Protocol by Transfer Types This section describes in detail USB protocol for various transfer types The control transfer is different from the other transfer types as it is completed over a few USB frames The other transfer types are completed within a frame 2 9 1 Control Transfers Control transfers have two or three stages setup data may or may not be required and status stage The best way to understand how a control transfer works is to look at an example as shown in Figure 2 13 It shows a complete control transfer between a function and a host as captured by a CATC USB bus analyzer see Chapter 3 for a more detailed discussion of a bus analyzer Packet Syne 09000001 SOF OxA5 Frame 0x12C CRCS 0x1F start of setup stage 180 Syne 00000001 SETUP 0xB4 ADDR 0x08 ENDP 0x0 CRCS Ox06 181 Sync 00900001 DATAO 0xC3 DATA 80 06 00 01 00 00 80 00 CRC16 0xB129 182 Syno Q0000001 ACK Ox4B 0 start of data stage 153 Sync 00000001 SOFLONAS Frame WEIER 184 Syne 00060007 IN Gx6 ASDR Ox08 ENDP Ox0 GRESK DS De Sync 0d000001 DATAT 0xD2 DATA 1z 01 00 01 00 00 00 08 CRC 16 0xC8E7 Syno 00000G01 ACK 0x4B 787 789 Syne 00000001 IN Ox96 ADDR Ox08 ENDP 0x0 CRCSOxOS 190 Syne 00000001 DATAD OxC3 DATA 86 80 AD OD 01 00 00 00 CRC16 0xC16F 192 Synce 0000001 SOF 0xA5 Frame H0x131 CRCS 0x15 Step 1 Understand the USB Specification 193 Syn
25. USB enumeration and among other things it has obtained the vendor and product identifications of the newly plugged in device However the host cannot find a corresponding information inf file that matches the product and vendor identifications of the device When this happens the host will ask for the location of the inf file so that it can load the correct driver Insert the enclosed diskette and direct the host to the location of the inf file which is in the floppy s root directory 91 Setting Up the Demonstration Update Device D riwer Wizard Figure 8 2 A unknown device screen on the host PC Note that this Update Device Driver Wizard process is only required when plugging in the device for the first time since the host PC could not find the corresponding inf file For subsequent plug in events the host will load the device driver without the Update Device Driver Wizard process and interactions from users This depicts the Plug and Play advantage of USB systems They can recognize the newly plugged in device and load the appropriate device driver automatically Once directed the host PC loads the inf file that matches the product and device identifications of the newly plugged in device Note that for the purpose of this example arbitrary product and device identifications are used You are required to change these identifications in the device firmware and inf file accordingly Based on the information in
26. UrbSelectConfiguration Interface set up the input parameters in our interface request structure interfaceObject gt Length GET USBD INTERFACE SIZE interfaceDescriptor gt b NumEndpoints interfaceObject gt InterfaceNumber interfaceDescriptor gt bInterfaceNumber interfaceObject gt AlternateSetting interfaceDescriptor gt bAlternateSetting interfaceObject gt numberOPipes interfaceDescriptor gt bNumEndpoints We set up a default max transfer size for the endpoints Your driver will need to change this to reflect the capabilities of your device s endpoints for j 0 j lt interface Descriptor gt bNumEndpoints j interfaceObject gt Pipes j MaximumTransferSize USBD DEFAULT MAXIMUM TRANSFER SIZE UsbBuildSelectConfigurationRequest urb USHORT siz ConfigurationDescriptor ntStatus Test_CallUSBD DeviceObject urb if NT_SUCCESS ntStatus amp amp USBD SUCCESS urb gt UrbSelectConfiguration Status Save the configuration handle for this device deviceExtension gt ConfigurationHandle 149 A WDM Driver Code Example urb gt UrbSelectConfiguration ConfigurationHandle deviceExtension gt Interface ExAllocatePool NonPagedPool interfaceObject gt Length if device xtension gt Interface RtlCopyMemory deviceExtension gt Interface interfaceObject interfaceObject gt Length Dump the pipe info for j 0 j lt interfaceObject gt NumberOfPipes j PUSB
27. a handle to an NT executive file object is returned to the application WDM Device Driver Example 6 5 WDM Device Driver Example To build WDM drivers we need both the Windows NT DDK and the WDM DDK with support for USB as mentioned in Chapter 3 The Windows NT driver model is documented in the Windows NT DDK The WDM USB DDK provides a set of header files software routines and libraries in addition to the Windows NT DDK to build the WDM drivers for USB devices A WDM driver example is provided in the USB program examples on the enclosed diskette and its usage is discussed in the Chapter 8 The following section should give you the basic overview of a typical code structure for a WDM driver As in any other Windows NT driver the DriverEntry routine is invoked when the driver is loaded It can be treated as the starting point of the driver code as the following example illustrates NTSTATUS DriverEntry IN PDRIVER_OBJECT pDriverObject INPUNICODE_STRING RegistryPath Purpose Main entry point for the driver wilt be invoked once when the driver is loaded PDEVICE OBJECT pDeviceObject NTSTA TUS ntStatus STA TUS_SUCCESS UNICODE_STRING objectName Set up dispatch entry points for the driver pDriverObject gt MajorFunction IRP_MJ_CREATE Test_Create pDriverObject gt MajorFunction IRP_MJ_ CLOSE Test Create pDriverObject gt MajorFunction IRP_MJ_DEVICE_CONTROL Test_ProcessIOCTL pDriverObj
28. and Windows NT are trademarks of Microsoft Corporation All other trademarks copyrights and registered names mentioned in this book are the property of their respective owners Annabooks has attempted to properly capitalize and punctuate trademarks but cannot guarantee that it has done so properly in every case Disclaimer The information or comments in this book reflects the author s own opinions it does not represent the view of Intel Corporation USB IF Microsoft or any other vendors The design example depicted in this book is not production worthy designers are required to modify the design to adhere to FCC and USB device class specifications Readers assume all risks if they wish to follow the example the author and publisher are not responsible or liable for any injuries or mishaps caused directly or indirectly by following the design example iii About the Author Wool Ming is a Senior Technical Marketing Engineer for Intel USB Microcontrollers He focuses on USB microcontroller architecture firmware development and the utilization of microcontrollers in various USB applications He has been involved in the USB world since the early days of USB development He provides technical consultations to various major OEMs and has helped them to develop and demonstrate their USB products at several international tradeshows Wooi Ming has a Master of Engineering Degree in Electrical and Electronics Engineering from the National
29. bits A field in a Universal Serial Bus packet that indicates the type of packet and by inference the format of the packet and the type of error detection applied to the packet Peripheral Component Interconnect A 32 or 64 bit processor independent expansion bus used on personal computers A device that has a physical implementation e g speakers telephones and CD players A logical abstraction representing the association between an endpoint on a device and software on the host A pipe has several attributes for example a pipe may transfer data as streams Stream Pipe or messages Message Pipe Phase Locked Loop A circuit that acts as a phase detector to keep an oscillator in phase with an incoming frequency Plug and Play A technology for configuring I O devices to use non conflicting resources in a host Resources managed by Plug and Play include I O address ranges memory address ranges IRQs and DMA channels Asking multiple devices one at a time if they have any data to transmit Plain Old Telephone Service Basic service supplied by standard single line analog telephones telephone lines and access to public switched networks A logical division of labor in an operating system For Windows NT it consists of a virtual address space an executable program one or more threads 104 Protocol Request Root hub Root port SCSI SFR s SOF Stage Synchronizatio n Type TDM Thread G
30. by a CATC bus analyzer tool see Chapter 3 for details and is shown to give a detailed insight into the USB bus enumeration process A USB bus reset is issued when the device first plugs into a USB hub or the root hub This is the followed by the GET DESCRIPTOR device setup packet as shown in packets 29 and 30 The 2nd byte value of 06H of the data packet 30 indicates that this is a GET DESCRIPTOR command as stated in Section 9 3 of the USB Specification Packet Syne 00000001 SOF OxA5 Frame 0x48E CROS OXOF 29 Sync 00000001 SETUP 0xB4 ADDR 0x00 ENDP 0x0 CRC5 0x08 30 Sync 00000001 DATA DATA E0 06 00 01 00 00 80 00 CRCO16 0xB129 The device we plugged in acknowledges the reception of this GET DESCRIPTOR device packet and issues an ACK packet 31 handshake The device then replies to the following IN token with an 8 byte data packet as shown in packet 34 Note that the last byte of this packet is 08H which indicates the size of endpoint 0 of the device 32 Sync 00000001 SOF OxAS Frame 0x490 GROS 0x07 3 33 Sync 00000001 IN 0x86 ADDR Ox00 ENDP 00 CRC5 0x08 _ 34 35 Sync 00000001 DATA 1 0xD2 DATA 12 01 00 01 00 00 00 08 CRC16 0xC8E7 Synot 000001 AGK Ox4B The host receives the packet from our device successfully and it sends an ACK handshake back to our device as indicated by packet 35 36 Sync 00000001 SOF OxA5 Frame 0x491 CRCS 0x18 The hos
31. configurationDescriptor Free data buffer At return ntStatus NTSTATUS Test_SelectInterfaces IN PDEVICE OBJECT DeviceObject IN PUSB CONFIGURATION DESCRIPTOR ConfigurationDescriptor IN PUSBD INTERFACE INFORMATION Interface Initializes a Test Device with multiple interfaces DeviceObject pointer to the device object for this instance of the Test Device ConfigurationDescriptor pointer to the USB configuration descriptor containing the interface and endpoint descriptors Interface pointer to a USBD Interface Information Object If this is NULL then this driver must choose its interface based on driver specific criteria and the driver must also CONFIGURE the device If it is NOT NULL then the driver has already been given an interface and the device has already been configured by the parent of this device driver Return Value NT status PDEVICE EXTENSION deviceExtension NTSTATUS ntStatus 147 A WDM Driver Code Example PU RB urb ULONG siz numberOfinterfaces j UCHAR numberOfPipes alternateSetting MylnterfaceNumber PUSB INTERFACE DESCRIPTOR interfaceDescriptor PUSBD_INTERFACE INFORMATION interfaceObject deviceExtension DeviceObject gt DeviceExtension MylnterfaceNumber SAMPLE INTERFACE NBR if Interface NULL This example driver only supports one interface This can be extended to be a dynamlCally allocated array by your driver numberOflnterfaces ConfigurationDe
32. done with the buffer dec A If it s not zero dec the upper byte as well mov ControlBuffBytesLeft A And store it RAMCheckMaxPacket cjne RO EPO MAX PACKET SIZE DatalnRAM Loop until FIFO is Full ControlTxUpd mov ControlBuffLocation 1 DPH Update read pointers mov ControlBuffLocation 2 DPL ControlArmTx mov TXCNTO RO Write count into TXCNT register setb TXOE Enable data transmit ReturnLoadCntl pop DPX pop RO Ret DEVICE DESCRIPTOR 8x930Ax is a Big Endian Microcontroller Words and DWords are stored with the LSB in the numer1Cally higher address FUNCTION DESCRIPTOR Users are required to change the descriptor accordingly BEGIN DEVICE DESCRIPTOR gDevice_bLength db 12h DEVICE DESCRIPTOR LENGTH gDevice_bDescriptorType db DEVICE DESCH gDevice_bcdUSB dw 0001h Version 1 00 compliant 125 Firmware Code Example For Intel 8x930Ax USB Microcontroller gDevice bDeviceClass db 00h gDevice_bDeviceClass db 04h for testing gDevice_bDeviceSubClass db Olh gDevice_bDeviceProtocol db 00h gDevice_wMaxPacketSizeO db 08h 8 byte max for EPO gDevice_widVendor dw 8680h Intel Vendor ID 8086 gDevice_widProduct dw 4956h product ID gDevice_widProduct dw 8888h gDevice bedDevice dw 000 1h device version 1 00 gDevice iManufacturer db Oh These three fields are supposed gDevice iProduct db Oh to contain the index of strings gDevice iSerialNumber db Oh descr
33. endpoint and so forth The sample code on the enclosed disk gives an example of how to configure these endpoints 5 3 2 Un enumerated Stage After the initialization of the device it proceeds to the un enumerated stage In this stage it will perform some non USB functions or just loop endlessly waiting for a setup token When a setup token arrives an interrupt will be generated and the device will execute its interrupt service routine ISR to handle the reception of the setup token After the first setup token the USB host will issue a series of IN OUT and SETUP packets to enumerate the device and the device is required to respond accordingly The enumeration process has been discussed in detail in Chapter 2 of this book After successful completion of the enumeration process the device proceeds to the idle stage looping endlessly or performing some application specified codes as shown in Figure 5 1 From this stage it can transit to either 1 transmit 2 receive 3 setup or 4 receive SOF interrupt service routines depending on the application 5 3 2 1 Transmit Routine for non isochronous transfer The transmit routine is used to transmit data to the host through non isochronous endpoints For example say the 8x930Ax is in a USB keyboard and endpoint 3 is configured as an interrupt endpoint during enumeration The device is now in its idle stage as shown in Figure 5 1 When a key is pressed an interrupt is generated and
34. is where the first line of code should be placed 4 1 3 External Memory Interface There are two modes available for the 8x930Ax to interface to external memory page and non page modes In non page mode the lower address A0 A7 and data byte D0 D7 are multiplexed using port 0 In this mode it takes two states to fetch a code from external memory with 0 wait state On the other hand using page mode a code can be fetched in one state time In this page mode the data D0 D7 is multiplexed with higher address byte A8 A15 in port 2 as shown in Figure 4 3 128 Kbyte 8x930Ax Flash Figure 4 3 Page mode for external memory access In this mode the first code fetch takes two states But for successive code fetches that are within the same 256 byte block of memory it only requires one state This is because the ALE latches the higher address 40 Step 3 Developing The Device Hardware A8 A15 only once and the address that was latched previously is reused for subsequent code fetches that are within the same 256 byte block Port 2 is now available to serve as the data bus while port 0 carries the lower address byte The ALE is not asserted for the second fetch so this fetch takes only one state time Another advantage of limiting the toggling of ALE signal is the reduction of unwanted electromagnetic radiation For data reads and writes to RAM devices for example three states are required either in page
35. management SetupTxFlag ds I SetupRxFlag ds I COMMAND BUFFER StandardDeviceRequest bmRequestType ds I bRequest ds 1 w Value wFeatureSelector bDescriptorType ds 1 bDescriptorlndex ds 1 wTargetSelector wiIndex ds 2 wLength ds 2 CntlWriteDataBuffer ds 8 CntlWriteDataPntr ds 1 Used to point into the CntlWriteDataBuffer ControlBuffLocation ds 3 ControlBuffBytesLeft ds 2 Beat ds 2 END 127 Appendices 11 2 A WDM Driver Code Example USB device driver for USB Device Example kernel mode driver JI to be compiled with H NT 4 0 DDK MSDN DDK Jan 97 release or later USB DDK Aug 96 release or later define DRIVER Include files needed for WDM driver support from NT DDK include wdm h include stdarg h inelude stdio h Include files needed for USB support from USB DDK include usbdi h include usbdlib h include usb h include Testdrv h headers specified to this driver We NTSTATUS DriverEntry IN PDRIVER OBJECT DriverObject IN PUNICODE STRING RegistryPath ie point for loading of the driver This is where the driver is called when the driver is being loaded 129 A WDM Driver Code Example by the I O system DriverObject pointer to the driver object RegistryPath pointer to a Unicode string representing the path to driver specific key in the registry Return Value STATUS SUCCESS if successful STATUS_UNSUCCESS
36. modifying the CREATESTRUCT cs return CFrameWnd PreCreateWindow cs CMainFrame diagnostics ifdef_ DEBUG void CMainFrame Assert Valid const CFrameWnd AssertValidQ void CMainFrame Dump CDumpContext amp dc const CFrameWnd Dump dc endif DEBUG CMainFrame message handlers void CMainFrame OnDevdesc TODO Add your command handler code here void CMainFrame OnConfdesc TODO Add your command handler code here void CMainFrame OnAlldesc TODO Add your command handler code here 164 Appendices void CMainFrame OnStrdesc TODO Add your command handler code here void CMainFrame OnInfdesc TODO Add your command handler code here void CMainFrame PostNcDestroy TODO Add your specialized code here and or call the base class CFrameWnd PostNcDestroy 165 An Application Software Code Example test app cpp Implement the class behaviors for the application software rev 1 0 include stdafx h include Test_app h include MainFrm h include T_appDoc h include T_app View h include main h include devioctl h include testdrv h ifdef_ DEBUG define new DEBUG NEW undefTHIS FILE static char THIS_FILE _FILE endif BEGIN MESSAGE MAP CUsbappApp CWinApp AFX_ MSG MAP CUsbappApp ON_COMMAND ID_APP_ABOUT OnAppAbout added here as well for set and get N CO
37. or non page mode We can add extra wait states up to three wait states or use the real time wait function if we are interfacing to slower devices With 0 wait state a byte can be read or written in three state time This gives the maximum throughput of 1 byte 3 oscillator clock cycles at 12 MHz i e 32 Mbps without taking into account other firmware overhead The 8x930Ax also has four 8 bit I O ports for general propose use Ports 0 and 2 will be occupied if code execution is from external memory Port 0 has an open drained structure and ports 1 2 and 3 have weak pull ups 4 1 4 Interrupt System The 8x930Ax employs a program interrupt method where the interrupt operation branches to a particular address space called the Interrupt Service Routine ISR vector address and performs a subroutine as stated by the instructions in that vector address When the subroutine completes and the return interrupt instruction RETI is issued the execution of the program resumes at the point where the interrupt occurs For example assume that we are executing our program looping from a program counter ranging from FF 0200H to FF 0500H When an interrupt occurs caused by say timer 1 the value of the program counter before branching to the ISR will be stored into a stack and the program execution will vector to the address of the timer I ISR which is FF 001BH The 8x930Ax would execute whatever instructions are at that location and when it finish
38. specific firmware for the device will require some minor changes For example if the microcontroller is used in a USB keyboard it is still required to scan the keyboard and encode the data when a key is pressed However after encoding the data the microcontroller is required to transfer the data to its transmit FIFO to get ready for 49 Firmware Relationship with Device Class Driver transmission through the USB wires For the ease of debugging you can develop the firmware in two separate modules initially one for USB related routines and the other for application specific routines When the two firmware modules are fully tested you can then integrate them together The USB firmware provided with this book will give you a good start in developing the USB routines You will need to develop the application specific routines separately and then merge them together for the USB device 5 2 Firmware Relationship with Device Class Driver The firmware developed for the device must work closely with the device driver on the host and thus the firmware designers and device driver designers are often required to work closely together There are various device drivers available bundled together with Microsoft Windows 95 and future operating system releases If drivers are available for the class of device you intend to develop you are not required to write your own driver What you are required to do is to follow exactly the device class specificat
39. the inf file the host PC can determine which driver to load and will then ask for the location of the driver as shown in Figure 8 3 The driver testdrv sys is located in the root directory of the enclosed disk so choose the Other Locations button and direct the host to the correct drive The host PC will then load the driver into its operating system This completes the loading of the WDM driver for the newly attached USB device 92 USB Application Software WDM Driver and Firmware Examples Figure 8 3 Loading process of WDM driver for the newly attached device Now activate the host application software test_app exe located in the root directory of the floppy to communicate with the USB device An Untitled A Simple USB Program Example user interface as shown in Figure 8 4 should appear Figure 8 4 Test_app exe application software user interface If the driver is loaded successfully the Get Descriptors Set Command and Get Command menu items are highlighted not grayed as shown in Figure 8 4 You can activate these menu items to perform some simple USB transactions as shown in Figure 8 5 Various USB packets will be generated and can be seen if you insert a bus analyzer in the USB wires path as shown in Figure 8 6 93 Setting Up the Demonstration Figure 8 5 Activate the menu item to generate a USB transaction vE CATE LISB Detective DATA USB CATE Default View
40. the microcontroller activates its scanning sequences to determine which key was pressed as shown in Figure 5 2 After identifying which key was pressed the microcontroller will load appropriate data into the FIFO of transmit endpoint 3 and then write a byte count to the byte count register of endpoint 3 After that it would go back to the idle stage waiting for the next interrupt When an IN token arrives for this endpoint 3 the SIE would automatically transmit the data that was in the FIFO to the host When the transmission completes a transmit done interrupt will be generated as shown in Figure 5 2 The microcontroller will then service this interrupt by checking corresponding flags and status registers to ensure that the transmission was completed successfully This signifies the completion of the transmit routine and the device will go back to its idle application stage as shown in Figure 5 1 52 Step 4 Develop the Device Firmware Firmware Hardware interrupt say from keyboard ISR move data to TXDAT write to TXCNT IN token RETI DIE of Sx930Ax transmits data to USB wires automatically ATM 1 transmit done interrupt ISR check status EE RETI Figure 5 2 Operation of transmit routines 5 3 2 2 Receive Routine for non isochronous transfer The receive routine is used when receiving data from the host using non isochronous transfer For example assume a USB printer has endpoint
41. the endpoints For full speed devices the endpoint can specify the polling period of 1 ms to 255 ms For low speed devices the polling period is from 10 ms to 255 ms Thus the fastest polling frequency is I kHz for full speed devices In case of delivery failure due to errors a retry of transfer will be carried out in the next polling period A good example of a device using interrupt transfer is a keyboard where it sends a small amount of data to the host when a key is pressed 4 Bulk Transfer The bulk transfer can be uni or bi directional It is used to support endpoints that need to communicate large amounts of data accurately but where the time of delivery is not critical The bulk transfer is designed to claim unused bandwidth of the USB and therefore the provision of USB access time to bulk transfers is on a bandwidth available basis In case of delivery failure due to errors the transfer is retried A typical usage is a scanner where a large amount of data needs to be delivered accurately but not immediately Step 1 Understand the USB Specification 2 7 USB Mechanical and Electrical There are two types of USB connectors series A and series B Series A connectors are shown in Figure 2 4 Figure 2 4 USB connectors series A Series A connectors are used to connect to downstream devices For example there are series A connectors on the back of a USB PC where the root hub is located Series B connectors are used to c
42. the other one for the USB suspend resume or reset interrupt The transmit and receive interrupts occur when a non isochronous endpoint is transmitted or received in a USB packet When an endpoint is configured as isochronous no interrupt occurs from the reception or transmission of a USB packet In this case we use the SOF interrupt to manage the data of this endpoint The SOF interrupt occurs when a SOF packet is received every 1 ms or when a SOF packet should have been received this is the case when the so called artificial SOF is received The artificial SOF is generated internally by the 8x930Ax frame timer to simulate the reception of the SOF when the true SOF packet is not received successfully The suspend or resume interrupt occurs when there are suspend or resume conditions detected on the USB wires For the case of suspend interrupt the USB module of the 8x930Ax will issue a USB suspend interrupt when there are no USB bus activities detected for more than 3 ms as defined by the USB Specification 42 Step 3 Developing The Device Hardware 4 1 5 8x930Ax On Chip Peripherals There are a number of peripherals integrated in the 8x930Ax to give users greater flexibility in using the microcontroller They include three timers counter units a hardware watchdog timer a programmable counter array PCA and a serial port UART 4 1 5 1 Timer Counter Units There are three general purpose timer counter units in the microcontrolle
43. this is a no data command then Process it mov CntlWriteDataPntr 0 Initilize the data pointer for future control write data stages ret If we are expecting data then don t Process the command yet ret and wait for the rest of the data to come in SetupGetCommand mov SetupRxFlag STATUS_ PHASE Advance flag to next state mov SetupTxFlag ADATA PHASE Ch9Decode to decode the bMRequestType according to chapter 9 of the USB spec we decode the bmRequestType first gt Ch9Decode mov A bmRequestType Get the value check standards commands jb ACC 6 OthersCommands jb ACC 5 OthersCommands divide into set or get commands jb ACC 7 GetCommands ljmp SetCommands 114 Appendices GetCommands anl ACC 1FH ignore bit 5 6 7 bit since they have been decoded cjne A 00H next_c01 ljmp StandardGetDeviceCommand next c01 cjne A 01H next c02 ljmp StandardGetlnterfaceCommand next c02 cjne A 02H next c03 ljmp StandardGetEndpointCommand next c03 cjne A 03H next c04 ljmp StandardGetOtherCommand next c04 ljmp OthersCommands SetCommands anl ACC 1FH ignore bit 5 6 7 bit since they have been decoded cjne A 00H next_cl1 ljmp StandardSetDeviceCommand next c11 cjne A 01H next c12 ljmp StandardSetInterfaceCommand next c12 cjne A 02H next c13 ljmp StandardSetEndpointCommand next_cl3 cjne A 03H next_cl4 ljmp StandardSetOtherCommand next cl4 Other
44. translates to 83 33 ns Compared to the accumulator based architecture of its predecessor the 8xC51Fx with a MCS 51 core which required two instructions and 12 state times one state time is two oscillator clocks for 8xC51Fx to achieve the similar goal MOV A RO requires 6 state time MOV R6 A require 6 state time At a 12 MHz crystal frequency the 8xC51Fx takes 83 33x2x6x2 1999 92 ns to complete these two instructions to achieve the transfer of data from RO to R6 4 1 2 Memory Organization In terms of addressing space the 8x930Ax can address up to 256 Kbytes providing you with greater flexibility Figure 4 2 shows the addressing space of the 8x930Ax Note that the MCS 251 core has the capability of addressing up to 16 Mbytes of address space but the 8x930Ax is limited to 256 Kbytes 38 Step 3 Developing The Device Hardware configuration array 8 bytes FF FFFFH to FF 0000H external memory on chip ROM 0 8 16 Kbytes FE FFFFH to FE 0000H reserved and not implemented for 8x930Ax 01 FFFFH to 01 0000H external memory 00 FFFFH to 00 0000H on chip RAM 1 Kbytes 4 banks of RO R7 32 bytes Figure 4 2 8x930Ax addressing space when configured to 256 Kbytes of addressing This 256 Kbyte is user selectable however so you can choose whether you would like to have 256 Kbyte 128 Kbyte or 64 Kbyte of addressibility by programming the configuration bytes of the 8x930Ax The config
45. 0310 PCINCC 0C0300 DeviceDesc UniversalHCD Dev PCNCC_0C0300 USBIROOT HUB DeviceDesc StandardHub Dev USB ROOT HUB OpenHCD DEV AddReg OpenHCD AddReg USB AddReg 73 Loading the WDM Drivers CopyFiles OpenHCD CopyFiles USB CopyFiles OpenHCD AddReg HKR NTMPDriver openhci sys HKR EnumbPropPages sysclass dll USBEnumPropPages OpenHCD CopyFiles openhcisys UniversalHCD Dev AddReg UniversalHCD AddReg USB AddReg CopyFiles UniversalHCD CopyFiles USB CopyFiles UniversalHCD AddReg AKR NTMPDriver uhcd sys AKR EnumPropPages sysclass dll USBEnumPropPages Universal HCD CopyFiles uhcd sys StandardHub Dev AddReg Hub AddReg CopyFiles Hub CopyFiles Compaq Compag Section PCIVEN OEII amp DEV AO0F8 DeviceDesc 0OpenHCD Dev PCIVEN OEI I amp DEV_AOFS A Intel Intel Section PCI VEN 8086 amp DE V 7020 DeviceDesc UniversalHCD Dev DCH VEN_80 86 amp DEV_7020 USB VID_8086 amp PID_9303 DeviceDesc StandardHub Dev USB VID 808 6 amp PID_9303 Philips Philips Section USB VID_0471 amp PID_0201 DeviceDesc StandardHub Dev USB VID_047 1 amp PID_0201 74 Step 5 Develop the USB Driver NEC NEC Sect ion USB VID 0409 amp PID 55AA DeviceDesc StandardHub Dev USB VID_040 9 amp PID_55AA Generic HUB GenericHub Section USBI CLASS 09 amp SUBCLASS 01 DeviceDesc StandardHub Dev USB CLA AN O9 amp SUBCLASS 01 USB
46. 1 MCS 251 Core The MCS 251 core is considered to be the next generation core of the MCS 51 8 bit core that has been widely used for over 15 years The MCS 37 Overview of the 8x930Ax USB Microcontroller 251 has a 3 stage pipeline CPU core which offers higher performance as compared to the MCS 51 When the pipeline is full and code is executed from internal memory some instructions can be completed in one state time one state time is equivalent to one oscillator clock for the case of the 8x930Ax when its internal Phase Lock Loop PLL is enabled To enable the PLL pins PLLSEL2 PLLSEL1 and PLLSELO need to be pulled high high and low respectively The 8x930Ax is also binary code compatible to the MCS51 core Using MCS51 instructions in the MCS251 core gives users up to a five times performance improvement If new MCS 251 instructions are used many new instructions have been introduced to give 16 bit type of capability for example 16 bit multiplication and divide up to a 15 times performance improvement can be achieved over the MCS 51 core The MCS 251 core is designed with a register based architecture and has 40 byte registers that can be accessed as bytes words or double words The registers can also be used for register to register addressing For example we can move a byte between registers using just one instruction MOV R6 RO This instruction can be completed in one state time For the case of the 8x930Ax at 12 MHz this
47. 1 configured for bulk transfer in its initialization stage Note that the maximum packet size for bulk transfer is 64 bytes per transfer as specified by the USB Specification For bulk transfer however it is possible to have multiple transfers within a frame if the bus bandwidth is available To print a file the host will send an OUT token to endpoint 1 of the printer The SIE will automatically receive the data and place it in the receive FIFO of endpoint 1 The SIE will also update the corresponding receive byte count register with the total number of bytes received When this reception is completed a receive done interrupt will be generated and the microcontroller comes into action It will execute 53 The 8x930Ax Operating Model its receive interrupt service routine as shown in Figure 5 1 First it will check the corresponding flag and status register to ensure the correct reception of the data After that it will move the data received for storage manipulation or transfer to other printer chips The process is depicted in Figure 5 3 After this it will go back into its idle application stage waiting for another interrupt Firmware Hardware OUT token SIE of 8x930Ax receives data from USB wires automatically receive done interrupt ISR check status RETI Figure 5 3 Operation of receive routines 5 3 2 3 Setup Routines for control transfer Every USB device is required to have its endpoint 0 co
48. 4 74 COMMUNICATING TO THE WDM DRnNER 85 8 USB APPLICATION SOFTWARE WDM DRIVER AND FIRMWARE EXAMPLES eeseseseeseseesesevsesevsesesseneseesenevseseneesee 89 8 1 CONTENT DESCRIPTION OF THE ENCLOSED DISKETTE 00 90 8 2 SETTING UP THE DEMONSTRATION 9 8 3 DELETING DRIVER amp ID INFORMATION FROM THE HOST 95 9 CONCLUSION ee EE 97 10 GLOSSARY undres ia eiiean daei E 99 11 APPENDICES bi Seeerei 107 11 1 FIRMWARE CODE EXAMPLE FOR INTEL 8x930Ax USB MICROCONTRBOLLER 107 11 2 A WDM DRIVER CODE ENXAMPLE 129 11 3 AN APPLICATION SOFTWARE CODE EXAMPLE eocrnvevrnnvvrrnvsenns 161 XI Table of Figures FIGURE l 1 CHAPTER LAYOUT EE 4 FIGURE 2 1 USB BUS TOPOLOGY ao E 9 FIGURE 2 2 LOGICAL CONNECTIONS FROM HOST TO USB DEVICES 10 FIGURE 2 3 CONCEPT OF THE USB PIPES AND ENDPOINTS 0000000 10 FIGURE 2 4 USB CONNECTORS SERIES A 13 FIGURE 2 5 USAGE OF SERIES A AND SERIES B CONNECTORS 0000000000 13 FIGURE 2 6 CROSS SECTION OF A FULL SPEED USB CABLE evuevrovvvvvrree 14 FIGURE 2 7 CONNECTION OF EXTERNAL RESISTORS IN A FULL SPEED DEVICE jiccsusucsessdecscederu coos e 14 FIGURE 2 8 A USB TOKEN PACKET enn soesseeeenennssessssterreressssserrene 15 FIGURE 2 9 FID PACKET FORMAT 16 FIGURE 2 10 A USB SOF PACKET reronvvrrrrnrnnnnnnnnnnnvevsvnnnnnnnnnnnnnnneee 17 FIGURE 2 11 A USB DATA PACKET hvete gehen 17 FIGURE 2 12 A USB HANDSHAKE PACKET sneneeoeseoseeeee
49. 5 2 8 USB PACKET FORMATS ease be n 15 2 8 1 TOKEN PACK EWS Reese Seegen AEN e AE NENNEN 15 2 8 2 START OF FRAME PACKETS rrrnnvrrrrnrnnnnnrvnnnnnnsssrnnnnnsrvnnnns 17 2 8 3 DATAPACKETS EE E 17 2 8 4 HANDSHAKE PACKETS cccccccccccceeseessesceccsssseeeeeseeseesess 17 2 8 5 SPECIAL PACKETS EE 18 2 9 USB PROTOCOL BY TRANSPERTvbtES 18 2 9 1 CONTROL TRANSEERS ur Me 18 292 ISOCHRONOUS TRANSFER sssssneneesoesseeeeeeeresssssesrerreeee 20 2 9 3 BULK TRANSFER eege 20 204 TNTERROF FANER E 21 2 10 USB FUNCTIONS esverorennvnvvnvvernrnnnnvvnnnnsnernrnnvnnvunensvesnnsnvnnnuneesseen 21 2 10 1 USB ENUMERATION STEPS ccccccsesssessscescecseeseeseenee 21 2 10 2 A SNAP SHOT OF A TYPICAL USB Bus ENUMERATION 23 2 10 3 USB RESET SUSPEND RESUME amp REMOTE WAKEUR 27 DAD USB IOS entsteet 28 3 STEP 2 SET UP A DEVELOPMENT ENVIRONMENT 0000000 31 3 1 DEVELOPMENT ENVIRONMENT DEVICE SUE 31 3 2 DEVELOPMENT ENVIRONMENT HOST SUE 34 33 CONTACT NUMBERS deenen Edge Eege eler 35 4 STEP 3 DEVELOPING THE DEVICE HARDWARE ss00000000 37 41 OVERVIEW OF THE 8x930Ax USB MICROCONTROLLER 37 4 1 1 MCS 251 CORE ernn E RA 37 4 12 MEMORY ORGANIZATION ooveennnnevvvnnnnnnvvernnnneveennenener 38 413 EXTERNAL MEMORY INTERFACE 40 4 1 4 INTERRUPT SYSEEM e gd bn Al 4 1 5 8x930Ax ON CHIP PERIPHERALS cceeeeeeeeeeeeeeeeeeeeeee 43 4 1 6 8x930Ax USB MODULE as ean 44 4 1 7 SF
50. CLASS_09 DeviceDesc StandardHub Dev USB CLASS 09 PLX PLX Section PCI VEN 10BS amp DE Y 9060 DeviceDesc PLX Dev PCI VEN_10B5 amp DE V 9060 PLX Dev AddReg PLX AddReg USB AddReg CopyFiles PLX CopyFiles PLX AddReg HKR NTMPDriver pcspeak sys PLX CopyFiles pc speak sys Via VIA Section PCI VEN 1106 amp DEV 3038 DeviceDesc UniversalHCD Dev PCH VEN 11 O6 amp DEV 3038 Global USB AddReg HKR DevLoader NTKERN USB Copy Files usbdsys HUB AddReg HKR DevLoader NTKERN HKR NTMPDriver usbhub sys 75 Loading the WDM Drivers HUB CopyFiles ControlFlags DestinationDirs DefaultDestDir 11 System directory Strings Msft Microsoft USBClassName Universal serial bus controller Generic Mfg Standard USB Host Controller PCNCC_0C0310 DeviceDesc Standard OpenHCD USB Host Controller PCI CC_0C0300 DeviceDesc Standard Universal PCI to USB Host Controller USB ROOT_HUB DeviceDesc USB Root Hub Compaq Mfg Compaq PCIVEN OEII amp DEV AO0F8 DeviceDesc Compaq PCI to USB OpenHost Controller InteLMfg Intel PCI VEN 8086 amp DEV 7020 DeviceDesc Intel 8237ISB PCI to USB Universal Host Controller USB VID 8086 amp PID 9303 DeviceDesc Intel 82930HX Hub with 3 downstream ports Philips Mfg Philips USB VID_0471 amp PID_020LDeviceDesc Philips USB Hub NEC Mfg NEC USB VID_0409 amp PID_55AA DeviceDesc NEC USB Hub G
51. ControlBuffBytesLeft First check to see if any data is available orl A ControlBuffBytesLeft 1 to send jnz CntlDataA vail 123 Firmware Code Example For Intel 8x930Ax USB Microcontroller mov RO 0 if there is data do normal flow ljmp ControlArmTx if none do null packet CntlDataAvail mov RO 0 Number of bytes in FIFO Always lt 16 mov A DPXL JZ DatalnRAM Data is in ROM use instructions to pull from ROM DatalnROM mov A 00h move A A DPTR Get Data to transmit mov TXDATO A inc DPTR inc RO Increment the number of bytes in FIFO djnz ControlBuffBytesLeft 1 ROMCheckMaxPacket If not Zero then continue ROMCheckUpperl mov A ControlBuffBytesLeft If upper byte of wLength is also zero buffer is empty jz ControlTxUpd Are we done with the buffer dec A If it s not zero dec the upper byte as well mov ControlBuffBytesLeft A And store it ROMCheckMaxPacket cjne RO EPO MAX PACKET SIZE DatalnROM Loop until FIFO is Full ljmp ControlTxUpd Done with this FIFO Data is in RAM use instructions to pull from RAM DatalnRAM movx A DPTR Get Data to transmit mov TXDATO A inc DPTR inc RO Increment the number of bytes in FIFO 124 Appendices djnz ControlBuffBytesLeft 1 RAMCheckMaxPacket If not zero then continue RAMCheckUpper1 mov A ControlBuffBytesLeft If upper byte of ControlBuffBytesLeft is also zero buffer is empty jz ControlTxUpd Are we
52. D PIPE INFORMATION pipelnformation pipelnformation amp deviceExtension gt Interface gt Pipes j j if selectconfiguration request was successful else ntStatus STATUS NO MEMORY if urb alloc passed f Interface was not NULL return ntStatus Ee NTSTATUS Test_Read IN PDEVICE OBJECT DeviceObject IN PIRP Irp This function is called fora IRP MJ READ TODO Add functionality here for your device driver if it handles that IRP code 150 Appendices DeviceObject pointer to the device object for this instance of the Test device Irp pointer to IRP Return Value NT status NTSTATUS ntStatus STATUS SUCCESS return ntStatus I NTSTATUS Test Write IN PDEVICE OBJECT DeviceObject IN PIRP Irp This function is called fora IRP_MJ WRITE TODO Add functionality here for your device driver if it handles that IRP code DeviceObject pointer to the device object for this instance of the Test device Irp pointer to IRP Return Value NT status NTSTATUS ntStatus STATUS_SUCCESS return ntStatus We NTSTATUS Test_Create IN PDEVICE OBJECT DeviceObject IN PIRP Irp 151 A WDM Driver Code Example This is the Entry point for CreateFile calls from user mode apps apps may open Test x yyzz where yy is the interface number and zz is the endpoint address Here is where you would add code to create symbolic links between endpoints
53. DDR 0x02 ENDP 0x0 CRC5 Ox15 259 260 Sync 00000001 DATA 1 0xD2 DATA 09 02 19 00 01 02 00 40 CRC16 0xFFD9 Syne 00000001 ACK 0x48 261 Syne 00000001 SOF OxA5 Frame 0x56A CRC5 0x01 ne 00000001 SOF OxAS Frame HOx56B CROS 0x 1 E ne 00000001 IN Ox96 ADDR 0x02 ENDP 0x9 CRC5 0x15 ne 00000001 DATAQ 0xC3 DATA 19 09 04 00 00 01 00 00 CRC16 0xED68 kd mov 25 USB Functions 265 Sync 000001 ACK 0x4B Sync 00000001 SOF OxA5 Frame 0x58C CRCS 0x00 267 269 Syne 00000001 DATA1 0xD2 DATA OO 00 07 05 B1 03 08 00 CROTS ONBSFD Sync 00000001 SOF OxA5 Frame Ox56E CRC5 0x1D Sync 00000001 SOF 0xA5 Frame MOx56F CRC5 0x02 273 Sync 0000000t IN Ox96 ADDR 0x02 ENDP 0x0 GRCS 0x15 274 Sync 000001 DATAM XC3 DATA I0 ERC 16 0x82CE Synet 00000019 ACK Gx4B ne 00000001 SOF OxAS Frame 0x570 CROS Ox15 279 281 Sync 0000001 SOF 0xA5 Frame 0x572 CRC5 0xDB 282 Sync 00000001 SOF 0xA5 Frame 0x573 CRC5 0x17 More SOF packets appear here After the successful completion of the GET DESCRIPTOR configuration command the host issues a SET CONFIGURATION command as indicated by packet 4334 and our device is required to act accordingly The 2nd byte value of 09H packet 4334 indicates that this is a SET CONFIGURATION command 332 Syne 00000001 SOF DxAS Frame 0x5A5 CRCS Ox06 333 Sync 00000001 SETUP OxB4 ADDR 0x02 ENDP 0x0 CRO
54. Developing USB PC Peripherals Using the Intel 8x930Ax USB Microcontroller Wooi Ming Tan Annabooks San Diego Developing USB PC Peripherals D Wooi Ming Tan Published by Annabooks 11838 Bernardo Plaza Court San Diego CA 92128 2414 USA 619 673 0870 800 462 1042 Fax 619 673 1432 info annabooks com http www annabooks com Copyright Wooi Ming Tan 1997 All rights reserved No part of the contents of this book may be reproduced or transmitted in any form or by any means without the prior written consent of the publisher except for the inclusion of brief quotations in a review Printed in the United States of America ISBN 0 929392 38 8 First Printing July 1997 Information provided in this publication is derived from various sources standards and analyses Any errors or omissions shall not imply any liability for direct or indirect consequences arising from the use of this information The publisher author and reviewers make no warranty for the correctness or for the use of this information and assume no liability for direct or indirect damages of any kind arising from technical interpretation or technical explanations in this book for typographical or printing errors or for any subsequent changes The publisher and author reserve the right to make changes in this publication without notice and without incurring any liability Intel Microsoft and Win32 are registered trademarks Windows Windows 95
55. DeviceObject urb else I ntStatus STATUS NO MEMORY Get the length from the Urb length urb gt UrbControlDescriptorRequest TransferBufferLength ExFreePool urb else ntStatus STATUS_NO MEMORY return length 159 Appendices 11 3 An Application Software Code Example We MainFrm cpp implementation of the CMainFrame class include stdafx h Anclude Test_app h include MainFrm h ifdef_ DEBUG define new DEBUG_NEW undefTHIS FILE static char THIS FILE _FILE endif CMainFrame IMPLEMENT DYNCREATE CMainFrame CFrameWnd BEGIN MESSAGE MAP CMainFrame CFrameWnd AFX MSG MAP CMainFrame ON WM CREATEQ NYAFX MSG MAP END MESSAGE MAP extern CUsbappApp theApp static UINT indicators ID SEPARATOR status line indicator ID_INDICATOR_CAP S ID_INDICATOR NUM ID INDICATOR SCRL 161 An Application Software Code Example CMainFrame construction destruction CMainFrame CMainFrame TODO add member initialization code here CMainFrame CMainFrame 1 int CMainFrame OnCreate LPCREATESTRUCT IpCreateStruct d CString DevName CMenu pcMenu pcSubMenu int uDevCnt 0 uCnt 0 nTT 0 if CFrameWnd OnCreate IpCreateStruct 1 return 1 if Im wndToolBar Create this Im wndToolBar LoadToolBar IDR MAINFRAME TRACEO Failed to create toolbar n return 1 fail to create if m_wndStatusBar Cr
56. FUL otherwise Si NTSTATUS ntStatus STATUS_SUCCESS PDEVICE OBJECT deviceObject NULL DriverObject gt MajorFunction IRP_MJ CREATE Test Create DriverObject gt MajorFunction IRP_MJ CLOSE Test_Create DriverObject gt DriverUnload Test_Unload DriverObject gt MajorFunction IRP MJ DEVICE CONTROL Test_ProcessIOCTL DriverObject gt MajorFunction IRP MJ WRITE Test Write DriverObject gt MajorFunction IRP MJ READ Test Read DriverObject gt MajorFunction IRP MI PNP POWER Test Dispatch DriverObject gt DriverExtension gt AddDevice Test PnPAddDevice return ntStatus NTSTATUS Test_Dispatch IN PDEVICE OBJECT DeviceObject IN PIRP Ip 17 Dispacthing the IRPs sent to the device DeviceObject pointer to a device object Jm pointer to an I O Request Packet Return Value NTSTATUS K 130 Appendices PIO STACK LOCATION irpStack nextStack PDEVICE EXTENSION deviceExtension NTSTATUS ntStatus Irp gt IoStatus Status STATUS SUCCESS Irp gt IoStatus Information 0 Get a pointer to the current location in the Irp This is where the function codes and parameters are located irpStack loGetCurrentIrpStackLocation Irp Get a pointer to the device extension deviceExtension DeviceObject gt DeviceExtension switch irpStack gt MajorFunction case IRP MJ PNP POWER This IRP is for Plug and Play and Power Management messages for your device switch irpSta
57. IN token The firmware decodes the data received refer to Chapter 9 of the USB Specification and processes the data accordingly After various steps the code will perform a Ch9Decode subroutine where it responds appropriately to the token received This subroutine can be further expanded to handle other types of commands like class commands or vendor specified commands if needed or desired On the InReceived subroutine side it will first check the stage of the control transfer by using the user flags SetupRxFlag and SetupTxFlag The code can then respond accordingly You ll want to note one special case of control transfer i e SET ADDRESS where the device s address is to be set by writing to the FADDR SFR only after the status stage This is different from other control transfers because the executions of the commands are completed after the status stage rather than before 58 Step 5 Develop the USB Driver 6 Step 5 Develop the USB Driver This chapter describes how to go about developing the USB driver But first an introduction to the concept of device class specifications and device class drivers 6 1 Device Class Specification and Driver What is a USB device class In the context of USB a class is a grouping of devices that have certain attributes in common Grouping these devices together allows the development of a class specified host based driver This class specification serves as a framework defining the oper
58. MMAND ID GETDES DEVICE OnGetdesDevice OMMANDI ID SET ONE OnSetOne OMMANDI ID SET TWO OnSetTwo OG ZZ QQ OMMAND ID GET ONE OnGetOne OMMAND ID GET TWO OnGetTwo CC ZZ QQ N AFX MSG MAP Standard file based document commands 166 Appendices ON COMMAND ID FILE NEW CWinApp OnFileNew ON COMMAND ID FILE OPEN CWinApp OnFileOpen Standard print setup command ON COMMANDI ID FILE PRINT SETUP CWinApp OnFilePrintSetup END MESSAGE MAP CUsbappApp CUsbappAppQ TODO add construction code here Place all significant initialization in Initlnstance CUsbappApp theApp BOOL CUsbappApp InitInstance Standard initialization If you are not using these features and wish to reduce the size of your final executable you should remove from the following the specific initialization routines you do not need ifdef_ AFXDLL Enable3dControls Call this when using MFC in a shared DLL else Enable3dControlsStatic Call this when linking to MFC statically endif LoadStdProfileSettings Load standard INI file options including MRU Register the application s document templates Document templates serve as the connection between documents frame windows and views CSingleDocTemplate pDocTemplate pDocTemplate new CSingleDocTemplate IDR_MAINFRAME RUNTIME CLASS CUsbappDoc RUNTIME CLASS CMainFrame main SDI frame window 167 An App
59. QUEST USBD TRANSFER DIRECTION IN Direction Bit OUT 0 Reserved Bits 0x04 Request OxF 1 pTestCtrlDesc gt usControlCode Value OxFO 157 A WDM Driver Code Example 0x0 Index 0x00 pTemp Transfer Buffer NULL Transfer Buffer MDL 0x08 Transfer buffer length Size of display descriptor NULL ntStatus MakeUSBDCall pDeviceObject pUrb ExFreepool pUrb ExFreepool pTemp return ntStatus Ki We ULONG Test_GetConfigDescriptor IN PDEVICE OBJECT DeviceObject PVOID pvOutputBuffer ULONG ulLength Pi Gets configuration descriptors from the given device object DeviceObject pointer to the test device object pvOutputBuffer pointer to the buffer where the data is to be placed ulLength length of the buffer Return Value Number of valid bytes in data buffer Zb PDEVICE EXTENSION deviceExtension NULL NTSTATUS ntStatus STATUS_SUCCESS PURE urb NULL ULONG length 0 deviceExtension DeviceObject gt DeviceExtension urb ExAllocatepool NonPagedPool sizeof struct URB control DESCRIPTOR REQUEST 158 Appendices if urb if pvOutputBuffer UsbBuildGetDescriptorRequest urb USHORT sizeof struct URB CONTROL DESCRIPTOR REQUEST USB CONFIGURATION DESCRIPTOR TYPE descriptor type 0 index 0 language ID pvOutputBuffer transfer buffer NULL MDL ulLength buffer length NULL link ntStatus Test CallUSBD
60. Rs ASSOCIATED WITH THE USB MODULE eeee000 46 42 INTERFACE WITH THE 8X930AX erovvrrnnvnvvrrnnnnnnvrrnnrnuvernnnvnneee 48 5 STEP 4 DEVELOP THE DEVICE FIRMWARE 49 51 OVERVIEW OF EIRMWARERESOURCES 49 5 1 1 USB FIRMWARE OVERHEAD eovvvvvvvvvvvvvvvvvvvvvrvvvrrvsvessssen 49 5 1 2 APPLICATION SPECIFIC FIRMWARE somnornvernnnnnnevnnnnnnvnennr 49 52 FIRMWARE RELATIONSHIP WITH DEVICE CLASS DRIVER 50 53 THE 8x930Ax OPERATING MODEL rerevernnevernnnnnnernnnnenernnnne 50 53 1 INITIALIZATION ee SI 53 2 UN ENUMERATED STAGE ccccccceccccccccececececeeceeeceees 52 54 USB ENUMERATION CODE 56 6 STEP 5 DEVELOP THE USB DRIVER ssssssssssssssssssssssssesesssees 59 6 1 DEVICE CLASS SPECIFICATION AND DRIVER eseccceeeeceeecees 59 62 OVERVIEW OF WDM eerennnvernnvvnnnvennnernnnvennvennnvvnnunennnsvennnnnnvennne 60 63 WINDOWS NT SYSTEM ONERVIENW 62 6 3 1 WINDOWS NT STRUCTURE ceccccccseeececeeeeececeeees 64 64 WINDOWS NT I O SYSTEM OVERVIEW rovvvvvvnvvvnvvvvnnnnnnnnnnnnnnene 66 6 4 1 NT OBJECT MODEL ege EENS 67 65 WDM DEVICE DRIVER EXAMPLE eoeesnennvvvvnnnnnnvvnnnrnuvvsnnnnnnve 68 66 LOADING THE WDM DRnVERS 72 7 STEP 6 DEVELOPING HOST APPLICATION SOFTWARE 79 7 1 MICROSOFT DEVELOPER STUDIO ervvvvvvvvvvvvvvvvvvvrvvvvvevsevverrene 79 7 2 DEVELOP THE APPLICATION SOFTWARE USING APPWIZARD 80 7 3 LINKING APPLICATION SOFTWARE TO THE WDM DRIVER evvvvrnnn
61. S 0x15 334 336 ho sd or 0 Syne 00000001 DATAO OxC3 DATAO0 09 02 00 00 00 00 00 CRC 16 0xE468 Sync _0000001 ACK 0x48 Synet 00000071 SOF OxAS Frame 0x5A6 CRCS OxO4 Sync 0G000001 IN 0x96 ADDR Ox02 ENDP Ox0 CRCS Ox15 338 Syne 00000001 DATA1 0xD2 DATA CRC16 0x0000 Syncf 0000001 ACK 0x4B Syne 00000001 SOF DxA5 Frame 0x5A7 CRCSJOx1B Sync 00000001 SOF OxAS Frame 0x548 CRC5 0x08 342 Sync 00000001 SOF 0xA8 Frame 0x5A9 CRCS DX 14 After this last sequence of the enumeration the device is ready for use Step 1 Understand the USB Specification 2 10 3 USB Reset Suspend Resume and Remote Wakeup USB devices are required to conform to the USB reset suspend and resume signaling The remote wakeup capability of a device is optional The reset signal is to ensure the robustness of the USB device When the USB device sees a SEO single ended zero both D and D are low on the USB wires for more than 2 5 usec it s required to treat the signal as a USB reset signal Typically the host issues a USB reset signal of 10 ms in length After the USB reset is removed all devices that receive the reset signal are set to their default address and are in the unconfigured state default stage All devices must be able to accept new device addresses via a SET ADDRESS setup token no later than 10 ms after the reset is completed see section 7 1 4 3 USB Specificatio
62. SC HKEY LOCAL MACHINE i EJ Conlig HO Enum 9 BIGS Figure 8 7 Locating the product information in the registry To delete the corresponding driver example testdrv sys or the inf file test inf use the Windows Explorer or MS DOS commands The driver is located in the windows system directory and the inf file is stored in the windows inf other directory a hidden directory 95 Conclusion 9 Conclusion We have discussed all the major steps and tasks required to develop USB devices We have covered the synopsis of the USB specification rev 1 0 development environment tool requirements a USB microcontroller and its firmware operating model WDM driver device class specification and host application software We have also investigated the interactions and communications between the host application software and the WDM driver of the USB device Code examples of the host application software WDM driver and device firmware are included on the enclosed diskette and in the Appendices for your reference The code examples and steps to use the code examples are also discussed in Chapter 8 of the book Although these codes are not production worthy they give you a good insight into USB systems from both the host side and the device side These codes can be used as a reference and can be further improved and modified to ensure their robustness and conformance to the USB protocol device class FCC and other relevant spe
63. SCRIPTOR device descriptor type setup packet to the device and the device needs to respond accordingly After the first GET DESCRIPTOR device packet an IN token will be issued and the device is required to reply accordingly Among the data sent to the host in the device descriptor packet is the actual maximum data payload size the device can handle The host will use this information for subsequent communication to this device After the successful reception of the descriptor packet the host will issue a SET ADDRESS command 6 Using this SET ADDRESS command the host assigns a unique address to the device This moves the device to the address stage 7 The host then issues a GET DESCRIPTOR device again as the previous GET DESCRIPTOR command is terminated pre maturely 8 After successful completion of the previous step the host issues a GET DESCRIPTOR configuration descriptor type setup packet to acquire the configuration of the device 9 Based on the configuration information received the host assigns a configuration value to the device via SET CONFIGURATION setup packet The device if bus powered may now draw the amount of Vos power described in its configuration The device is now in the configured stage refer to Figure 2 14 and is ready for use 22 Step 1 Understand the USB Specification 2 10 2 A Snap Shot of a Typical USB Bus Enumeration A typical communication flow during a USB enumeration is captured
64. TROL provides device control functions to the devices as required by the application In the example provided the get command one menu is activated in the application program causing the application thread to issue an IRP request IRP Test GET CONFIGURATION DESCRIPTOR The request will eventually cause the activation of the Test ProcessIOCTL routine as directed by the IRP MJ DEVICE CONTROL The Test ProcessIOCTL routine will then further decode the IRP After decoding the IRP command in the Test_ProcessIOCTL routine a USB Request Block URB will be made in the Test GetConfigDescriptor routine This is followed by the Test CallUSBD routine to perform the USBD call and carry out the corresponding USB functions In the ex ample below the Test_ProcessIOCTL Test_GetConfigDescriptor _UsbBuildGetDescriptorRequest and Test_CallUSBD routines will be called in the sequence as stated when the IRP Test GET CONFIGURATION DESCRIPTOR IRP is made by the application software 69 WDM Device Driver Example example to handle the IRP MJ DEVICE CONTROL DriverObject gt MajorFunction IRP MJ DEVICE CONTROLJ Test ProcessIOCTL K NTSTATUS Test_ProcessIOCTL INPDEVICE_OBJECT DeviceObject IN PIRP Irp PIO STACK LOCATION irpStack PVOID ioBuffer ULONG inputBufferLength ULONG outputBufferLength PDEVICE EXTENSION device Extension ULONG ioControlCode NTSTATUS ntStatus ULONG lengt
65. University of Singapore and a Bachelor Degree in Engineering from the University of Canterbury New Zealand His Master s research was on the behavior of the third generation digital cordless protocols in fading channels He has programmed in C C and various microcontroller assembly languages using the IBM PC DOS Windows operating system VAX VMS and UNIX environments He has experience with data networks and VAX VMS systems planning and management and in the manufacturing of wireless communications systems IV Dedication This book is dedicated to my parents my wife Pat and my sisters Nee and Ling Acknowledgements The author would like to thank all the members of the USB team from CEG Chandler and Penang 1AL and the USE IF for their support VII Contents 1 WHAT WILL THIS BOOK DO FOR YOU2 sssssssssssssssssssssssssssssoees 1 1 1 WHAT is USB ANYWAY H 2 1 2 OUTLINE OF THE BOOK asked eden bes dedeaeedeeuees 3 E Wd EE H 1 4 FEEDBACK TO THE EE ees ENEE 5 2 STEP1 UNDERSTAND THE USB SPECIFICATION sssssesssse0000 7 2 1 SUMMARY OF USB PROTOCOL c cccccsssseececccccessensseececcceeeanens 7 2 2 USB OBJECTIVES Eeer 7 2 3 USB BUS TOPOLOGY ege EEN 8 24 USB DATA FLOW MOD 9 25 USB PIPE CONCEPT DEVICE ADDRESS AND ENDPOINT 10 2 6 USB TRANSFER TYPES Luer eee an 11 2 7 USB MECHANICAL AND ELECTRICAL erovvvrnvrnvvvrnnnnvvvernnnnuvvenen 13 2 7 1 POWER SUPPLY FROM USB wirs 1
66. V TXDAT R6 move the data to transmit FIFO of endpoint 0 INC WR30 03 H increase our data pointer MOV R6 OWR30 move the next byte of data MOV TXDAT R6 INC WR30 01H and so on until we finish moving 10 bytes of data to TXDAT and then MOV TXCNTL 0AH write to the byte count register 45 Overview of the 8x930Ax USB Microcontroller After writing the byte count TXCNTL you can continue to perform other functions for the USB device When an IN token arrives for the endpoint 0 the SIE will transfer these 10 bytes AUTOMATICALLY into the USB wires with appropriate CRC bit stuffing and NRZI coding according to the USB Specification The FIFO size for endpoint pair I is configurable with 1 Kbyte total available If you configure the endpoint to be I Kbyte for transmitting 0 bytes in receiving and use the FIFOs in dual dataset mode for isochronous transfer it can transmit at the rate of 4 096 Kbps 512 byte per USB frame of 1 ms 4 1 7 SFRs Associated with the USB Module There are 26 Special Function Register s SFRs related to the operation of the USB module in the 8x930Ax microcontroller Their descriptions are shown in the following table Pee ee EPCON Endpoint Control Register To configure the operation of the endpoint specified by the EPINDEX It is used to configure stall enable control transmit and receive capability in the endpoint EPCONFIG Endpoint Configuration Register To select four endpoint pa
67. VICE_EXTENSION deviceExtension NTSTATUS ntStatus STATUS_SUCCESS deviceExtension DeviceObject gt DeviceExtension if deviceExtension gt DeviceDescriptor ExFreepool deviceExtension gt DeviceDescriptor Free up any interface structures in our device extension if deviceExtension gt Interface NULL ExFreepool deviceExtension gt Interface return ntStatus NTSTATUS Test_StopDevice IN PDEVICE OBJECT DeviceObject 137 A WDM Driver Code Example Stops a given instance of a test Device device on the USB DeviceObject pointer to the device object for this instance of a Test Device Return Value NT status PDEVICE_EXTENSION deviceExtension NTSTATUS ntStatus STATUS_SUCCESS PURB urb ULONG siz deviceExtension DeviceObject gt DeviceExtension Send the select configuration urb with a NULL pointer for the configuration handle this closes the configuration and puts the device in the unconfigured state siz sizeof struct URB SELECT CONFIGURATION urb ExAllocatePool NonPagedPool siz if urb NTSTATUS status UsbBuildSelectConfigurationRequest urb USHORT siz NULL status Test CallUSBD DeviceObject urb ExFreePool urb else ntStatus STATUS NO MEMORY return ntStatus We NTSTATUS 138 Appendices Test PnPAddDevice IN PDRIVER OBJECT DriverObject IN PDEVICE OBJECT PhysicalDeviceObject This Routine is called t
68. able image to point to DLL procedures at runtime 100 Downstream Driver Driver Object DWORD Endpoint Endpoint Address Environment Subsystem EOP EPROM EEPROM or E PROM Evaluation Kit File Handle Frame Glossary The direction of flow of communication from the host PC to its peripherals When referring to hardware it is an I O pad that drives an external load When referring to software it is a program responsible for interfacing to a hardware device A system object that represents a driver on the system and provides the address of the driver s entry points to the I O manager A driver object can be associated with multiple device objects See device object Double word Data that is two words in size four bytes or 32 bits A uniquely identifiable portion of a USB device that is the source or sink of information in a communication flow between a host and a device An address location specified in a USB token to a particular device A protected subsystem server that provides an application programming interface API andenvironment such as Win32 MS DOS OS 2 on Windows NT The subsystem captures API calls and implements them by calling Windows NT services End of packet Electrically Erasable Programmable Read Only Memory A non volatile memory storage technology In this book an evaluation kit for the Intel 8x930Ax microcontroller It consists of a 8x930Ax evalua
69. and play high performance and reduced overall system cost are just a few of the reasons this technology has gone from specification to product deployment in less than two years Wooi Ming Tan has provided in this book a very timely introduction to the concepts of USB as well as a very practical guide on how to design USB peripheral products With his early involvement in USB at Intel Corporation he has faced many of the design issues that engineers will likely encounter as they begin product development The book also provides a useful overview for those just interested in gaining a more thorough understanding of USB such as project management sales and marketing personnel involved in serial bus interconnect I am very pleased to see this book providing an easy step by step methodology to allow more USB products to quickly come to market while following a thorough design practice Wooi Ming Tan s experience in USB and microcontroller technology certainly comes across in the book allowing the reader to save many hours in USB peripheral design Stephen Whalley Chairperson USB Implementers Forum XV 1 What Will This Book Do For You Everybody talks about USB what is it Can USB benefit my current products How hard is it to understand USB How do we go about designing a USB device Where do I start There are USB hosts WDM USB devices firmware where can I get all the information I need all of this info in o
70. any Intel Microsoft NEC and Northern Telecom Many other companies now see the potential of USB and have jumped on the bandwagon To date the USB Implementers Forum has over 300 members PCs with USB connectors have started appearing in the market and many USB devices are currently available with more becoming available soon USB brings true Plug and Play convenience to PC users for the first time in PC history It makes the process of adding a new peripheral as What Will This Book Do For You easy as plugging a phone line into the connector on the wall We do not have to worry about the number of available ports the dip switches the jumpers the IRQs the installation guides etc All that is required to install a new peripheral is to connect the peripheral to a USB socket The PC will recognize the new device and activate the appropriate applications We can even install the device when the PC is up and running USB is truly Plug and Play Not only that USB also creates an opportunity for exciting new applications like digital cameras multimedia devices telephony devices and multi user games It opens up huge opportunities for companies to profit from these exciting PC devices This is what this book is all about guiding you step by step in developing a USB device The book is meant for anyone that wants to know more about USB and USB devices It also includes code examples on the enclosed diskette to give readers a thorough un
71. asynchronous serial port typically used on personal computers One of the four USB transfer types It supports configuration command or status type communi cations between client and function Cyclic redundancy check A check performed on the transmitted data to see if errors have occurred in transmitting reading or writing the data The CRC is typically stored or transmitted with the actual data and at the receiving end the stored or transmitted CRC is compared to a calculated CRC to determine if errors have occurred Computer Telephony Integration An address defined by the USB Specification and used by a USB device when it is first powered or reset to communicate to the host The default address is 00H A message pipe created by the USB host system software to communicate with USB devices A logical or physical entity that performs a USB function It may be referred to as a single hardware component a collection of hardware components or a function that provides specified services e g a fax modern device A system object that represents a physical logical or virtual device and describes its characteristics It is associated with a driver object See Driver Object Dynamic Link Library An application program ming interface API routine that user mode applications can access The code for the API routine is not included in the user s executable image Instead the operation system automatically links the execut
72. ation of devices belonging to that class This allows the development of class drivers from parties other than the manufacturer of the device itself For example a keyboard manufacturer does not need to include a driver if the keyboard class driver is bundled with the operating system and if he follows the device class specifications In fact keyboards belong to the HID human input device class of USB devices Thus the hardware vendors can concentrate on developing their hardware while other software driver vendors can design the drivers All USB devices must meet the USB specifications In addition to this a class specified device must follow the class requirements exactly The class specifications dictate how a USB device communicates with the driver Figure 6 1 illustrates the relationship between a USB device and the host In the bottom layer the hardware of the USB device communicates through the actual USB wires to the host hardware In the middle layer the USB system software uses USB specifications to communicate with the USB device In the highest level the client driver interacts with the device s functions as specified by the class specification 59 Overview of WDM Interconnect Function USB Device USB Bus USB Bus I nferface Interface Actual Communications Flow 4 Logical Communications Flow Figure 6 1 Relationship of the USB host and the USB device There are currently 11 classes defined in USB comm
73. cifications and regulations that are required for commercial devices Once a developed prototype reaches a certain stage of maturity you can participate in the USB PlugFest sometimes called the USB Compatibility Workshop to test the prototype The USB PlugFest is organized by the USB IF generally on a bi monthly basis for developers to test their prototypes to ensure conformance to various USB hosts Developers from host and device vendors can get together to test and debug their systems on a real time basis For more information about the PlugFest contact the USB IF http www usb org It is the purpose of this book to provide you with all the information needed about USB systems and how to develop USB devices With this guidance it is hoped that you can start developing your own USB devices make prototypes and build production units Get into the USB bus 97 ACK Apbuilder API Bandwidth Big Endian Bit Bit Stuffing bps Bulk transfer Bus enumeration Byte Client Glossary 10 Glossary Acknowledgment Handshake packet indicating a positive acknowledgment Software from Intel It helps you to become familiar with the 8x930Ax and other architectures Application Programming Interface A set of routines that you can make use of to request and carry out certain services performed by an operating system The amount of data transmitted per unit of time typically in units of bits per sec bps
74. ck gt MinorFunction case IRP MN START DEVICE We pass the Irp down first nextStack IoGetNextlrpStackLocation Irp ASSERT nextStack NULL RtlCopyMemory nextStack irpStack sizeof IO STACK LOCATION This will be deviceExtension gt StackDeviceObject in future revisions of this driver ntStatus IoCallDriver deviceExtension gt PhysicalDeviceObject Irp begin our configuration actions on the device ntStatus Test_StartDevice DeviceObject break IRP_MN START DEVICE case IRP MN STOP DEVICE Test Cleanup DeviceObject 131 A WDM Driver Code Example ntStatus Test_StopDevice DeviceObject break TRP_MN_STOP_DEVICE case IRP MN REMOVE DEVICE Test_Cleanup DeviceObject ntStatus Test RemoveDevice DeviceObject Delete the link to the Stack Device Object and delete the Functional Device Object we created IoDetachDevice deviceExtension gt StackDeviceObject loDeleteDevlce DeviceObject break IRP MN REMOVE _ DEVICE case IRP MN SET POWER switch irpStack gt Parameters Power Type case SystemPowerState case DeviceSpecificPowerState TODO Your device may need to handle these loctls break SystemPowerState amp DeviceSpecificPowerState case DevicePowerState switch irpStack gt Parameters Power State DeviceState case PowerDeviceD3 break case PowerDeviceD2 break case PowerDeviceD 1 break case PowerDeviceD0 break switch on Power State Devic
75. code For example an ICE enables emulating the performance of the 8x930Ax when code execution is performed from internal ROM The Evaluation kit as described earlier 33 Development Environment Host Side executes code from external memory The speed of code execution from external memory is slower than the speed of code execution from internal ROM thus making the internal ROM choice preferable if you have the available resources More detailed descriptions of the 8x930Ax microcontroller and its firmware operating model are available in Chapters 4 and 5 respectively 3 2 Development Environment Host Side On the host side two PC systems are recommended to develop the USB drivers and applications software To develop the USB drivers you ll need a PC running the Windows NT operating system version 4 0 or higher Microsoft Visual C C Professional Version 4 0 or higher and a subscription to the Microsoft Developer Network MSDN level II professional level The subscription to the MSDN is to obtain the Windows NT DDK and Win32 SDK please refer to the Contact Numbers section for more information You ll also need to obtain the USB DDK from Microsoft by contacting the e mail address usbbeta microsoft com or contact the USB IF This software then needs to be installed in the PCs the recommended sequence of installation of the software kits is as follows Windows NT first then Visual C Professional Edition 4 0 or higher follow
76. configurable Note that the 8x930Ax can also be configured to have six endpoint pairs by setting the SIXEPPEN bit in the EPCONFIG SFR see the 8x930Ax 8x930Hx USB Microcontroller User s Manual for details All the endpoints support isochronous and non isochronous transfer For example endpoint pair 0 can be configured as control endpoints as required by USB Specification endpoint pair I as isochronous endpoints endpoint pair 2 as bulk endpoints and endpoint pair 3 as interrupt endpoints All the FIFOs can support up to two datasets For example you can divide the transmit endpoint 2 into two data sets of 8 byte FIFOs Fill in the first 8 bytes of the dataset and while waiting for the USB token for this endpoint fill in the other 8 bytes for the second dataset for this same endpoint From the device point of view you only have to take care to fill in or take out the data from the FIFOs The rest of the USB requirements like CRC NRZI coding decoding bit stuffing etc are done by the SIE For example to transmit a packet of 10 bytes to the USB wires through endpoint 0 would require transferring the 10 bytes of data into the FIFO of endpoint 0 and then writing a byte count of 10 into the byte counter register In assembly language this would be assuming we have the 10 bytes of data in address location 00 A000H to 00 4009H MOV WR30 A000H MOV R6 WR30 R6 as temporary storage MOV EPINDEX 00H select endpoint 0 MO
77. derstanding of the steps involved in developing a USB device The disk includes sample code for USB firmware the WDM driver and application software as a reference for anyone who wishes to develop USB devices Use of this code is described in Chapter 8 1 2 Outline of the Book There are nine chapters in this book Chapters 2 through 7 consist of various steps required to develop a USB device as shown in Figure 1 1 Each of the chapters contain only relevant material to get you started in executing the steps References are quoted appropriately throughout the book to direct you to extra or more detailed information With this organization of the book readers who know USB for instance can skip Chapter 2 and go straight to Chapter 3 for the Development Environment I ll show you how some of the development tasks can be done in parallel thereby reducing the elapsed time to develop a USB device and shortening the time to market for the device The steps will be discussed in more detail in later chapters References Chapter 4 Introduction to this book Chapter 2 Step 1 Understanding the USB Specification Chapter 3 Step 2 Set Up a Development Environment p Chapter 4 Step 3 Build Device Hardware Chapter 5 Step 4 Develop Device Firmware Chapter 6 Step 5 Develop Host Driver Chapter 7 Step 8 Develop Application Software Siep 7 Integration Step 6 Testing T
78. discussion on how to create various menu items and other window functions can be found in Programming Windows NT Auer and Teach Yourself Visual C 4 in 21 Days Mer rout Devebser Sidin test fie cpp IN MESSAGE H F C boutDlg Dialog Ari CAFE WEG W ER al fe Do megsaga handlers sr lAAEZ NOG HAF MESSAGE MAP Ar App commend yun the dislog void CTost apn Arn ChhoutDlg aboutblg abaty Dolodalt TERESE EMAL et Po A RELI PEER FEE EE ETEN RE OPE PEE OEE OF e Figure 7 7 OnAppAbout routine 7 3 Linking the Application Software to the WDM driver As mentioned in Chapter 6 when a USB device is plugged into a host PC a corresponding driver will be loaded A symbolic link will also be created by the driver routine using IoCreateSymbolicLink during 84 Step 6 Developing Host Application Software the loading of this driver This symbolic link enables user mode applications to open and operate on the driver object On the application software side a file handle must be created to match the symbolic link that was created by the device driver For example consider the device driver with the following code in the device driver routines NTSTATUS DriverPnPPowerEvent loCreateSymbolicLink DosDevices TRYING_00 Devices T00 T00 is the object name created using IoCreateDevice routine This driver code can be linked to the application software using the following routine
79. e Developer Studio application icon To start a new application development choose File New from the application menu Then select the Project Workspace from the options given as shown in Figure 7 1 Micwitelt Developer gege Tools Window Help bk li You want to Comm rt on OCount The number of bytes te be 1 2 H return linefead pairs re counted H Aemarka Figure 7 1 Starting a new project workspace 80 Step 6 Developing Host Application Software After opening the new project workspace select the MFC AppWizard exe option to activate the AppWizard application to help build the skeleton software as shown in Figure 7 2 nfo Viewer Figure 7 2 Using AppWizard For the purpose of this example use the AppWizard to create a Single Document application To do this choose the Single document option as shown in Figure 7 3 H fe hee yee y Ipapippetawg Figure 7 3 Step 1 of the of the AppWizard 81 Develop Application Software using AppWizard There are several steps after the above Single document step You ll need to follow the setup routine and select the desired options according to the requirements of the application After completing all these steps the AppWizard will create a skeleton of the program A few program files will be generated accordingly type Single Document Interlace Application targeting Win3Z Grasses to be created Application CT est pp in last h and test
80. e USB Specification 186 Sync 00000001 ACK Dx4B 187 Syne 00000001 SOF OxAS Frame 0x52F CRC5 0x18 188 Sync 00000001 SOF OxA5 Frame 0x530 CROS DXOF Syne 00090001 IN 0x95 ADDR 0x02 ENDP 0x0 CRC5 0x15 190 Synet 000001 DATAQ OxC3 DATA 85 80 AD OD 00 01 00 00 CRC18 0xCB53 Sync 00000001 ACK Ox4B 192 Sync 00000001 SOFAS Frame 0x531 CRC5 0x10 Syne 00000001 SOF OxA5 Frame Mux534 GROS 0x13 Sync 00000001 OUT 0x87 ADDR 0x02 ENDP 0x0 CROS 0x15 Sync 00000001 DATA 1 0xD2 DATA CRC168 0x0000 Sync 00000001 ACK 0x4B 202 Sync 00000001 SOF OxA5 Frame 0x535 CRCS 0x0C 203 Sync 00000001 SOF OxAS Frame 0x536 CRC5 Ox0E Again more SOF packets are issued in this gap After finishing the GET DESCRIPTOR device command the host then issues a GET DESCRIPTOR configuration to our device as shown in packet 255 The 4th byte of this data 02H indicates a descriptor type of configuration Our device responds accordingly In the response the 3rd and 4th byte value of 0019H packet 259 indicates the length of data to be returned for this configuration For this case 25 bytes of data will be returned as shown in packets 259 264 269 and 274 252 Sync 00000001 SOF OxA5 Frame 0x567 CRCS Ox0C 53 Sync 00000001 SETUP OxB4 ADDR 0x02 ENDP 0x0 CRCS 0x15 Sync 00000001 DATAO 0xC3 DATA 80 06 00 02 00 00 80 00 CRC 16 0x8329 158 Sync 00000001 IN Gx96 A
81. e descriptor contents deviceDescriptor ExAllocatepool NonPagedPool siz if deviceDescriptor Use a macro in the standard USB header files to build the URB UsbBuildGetDescriptorRequest urb USHORT sizeof struct URB Control DESCRIPTOR REQUEST USB DEVICE DESCRIPTOR TYPE 0 0 deviceDescriptor NULL siz NULL Get the device descriptor ntStatus Test_CallUSBD DeviceObject urb else ntStatus STATUS NO MEMORY if NT SUCCESS ntStatus Put a ptr to the device descriptor in the device extension for easy access We will free this memory when the device is removed See the Test_RemoveDevice code deviceExtension gt DeviceDescriptor deviceDescriptor deviceExtension gt Stopped FALSE else if deviceDescriptor Tf the bus transaction failed then free up the memory created to hold the device descriptor since the device is probably non functional ExFreEP0ol deviceDescriptor ExFreEPOol urb else ntStatus STATUS NO MEMORY 136 Appendices II If the Get Descriptor call was successful then configure the device if NT_SUCCESS ntStatus ntStatus Test_ConfigureDevice DeviceObject return ntStatus NTSTATUS Test_RemoveDevice IN PDEVICE OBJECT DeviceObject Removes a given instance of a Test Device device on the USB DeviceObject pointer to the device object for this instance of a Test Device Return Value NT status e PDE
82. e generated if enabled when the microcontroller receives the SOF tokens An SOF interrupt will also be generated even if a valid SOF token is not received due to error In this case the interrupt is caused by an artificial SOF generated by the frame timer of the 8x930Ax The SOF routines are used to manage the transfer of isochronous data Its flow diagram is shown in Figure 5 4 Firmware 2 Hardware SOF interrupt ISR check status for previous cycle for transmit move data to TXDAT write to TXCNT for receive move data from RXDAT size as indicated by RXCNT IN or OUT tokens B SIE of 8x930Ax transmits S or receives USB data RETI automatically Figure 5 4 Operation of SOF routine 55 USB Enumeration Code For example say seven to nine bytes of data are stored every frame into internal RAM of the device from a 64 kbps PCM codec The SOF interrupt can be used to initiate transfer of these bytes into the transmit FIFO for transmission to the host The same SOF interrupt can also be used for the transfer of isochronous data from the host Note that you ll need to use the FIFO in dual packet mode for isochronous transfer The dual packet mode provides a method to match the rate of voice codec 64 kbps in this example to the USB rate of 12 Mbps The user manual of the 8x930Ax 3 describes the above routines in greater details 5 4 USB Enumeration Code A USB enumeration code example USB ENUM ASM
83. e most important concept designers need to understand In a multimedia USB device for example one of the endpoints may carry data one may carry voice and the other may carry control information All these packets are required to be treated differently for instance data for file transfers e g files to be sent to printers requires high accuracy in delivery often less than 1 x 107 in bit error rate On the other hand raw voice data can tolerate up to I x 10 in bit error rate but cannot tolerate excessive delay typically delay of gt 20 ms is considered bad However USB is designed to carry all of this different information and it can all be communicated with through the USB connection with the endpoint concept used to separate according to data type sources etc 2 6 USB Transfer Types There are four USB transfer types i e 1 control 2 isochronous 3 interrupt and 4 bulk 1 Control Transfer Control transfers are bi directional and intended to support configuration command or status communications between the host and functions A control transfer consists of 2 or 3 stages a setup stage data stage may or may not exist and status stage In the setup stage the host sends a request to the function In the data stage data transfer occurs in the direction as indicated in the setup stage and in the status stage the function returns a handshake to the host Each USB device is required to implement the endpoint pa
84. e root hub or a self powered hub port and the Ov ground GND A bus powered device can draw a maximum of 500 mA if attached to the root hub or a self powered hub The definition of a bus powered device is that the device draw current from the USB bus directly Devices that have their own power supply are called self powered devices Before the requested amount of current is granted by the USB host the device must draw no more than 100 mA from the USB when it first attaches to the bus For devices that are attached to a bus powered hub the maximum amount of current supply permitted is 100 mA section 7 2 1 of USB spec 1 0 2 8 USB Packet Formats USB packets fit into one of these types token SOF data handshake and special packets 2 8 1 Token Packets USB transaction are always initiated by the host and are started with a token packet in the format shown in Figure 2 8 SYNE PD Te CC ee GR Figure 2 8 A USB token packet 2 8 1 1 SYNC All packets begin with a synchronization SYNC field It is used by the input circuitry to align incoming data with the local clock and it is 8 bits in length 2 8 1 2 PID A packet identifier PID immediately follows the SYNC field A PID consists of four bits followed by a four bit check field as shown in Figure 2 9 Figure 2 9 PTD packet format 15 USB Packet Formats The PID indicates the type of packet that is transmitted differentiated by PIDo and PID either token data
85. e used to map to different components of our USB device 48 Step 4 Develop the Device Firmware 5 Step 4 Develop the Device Firmware This chapter describes the techniques in developing the device firmware using the 8x930Ax microcontroller Sample code for the USB enumeration process is included on the enclosed diskette ready for you to program into a 32 Kbyte EPROM or FLASH memory Once programmed this EPROM or FLASH can directly plug into the EPROM socket of the 8x930Ax Evaluation Board It will then be ready for USB enumeration when you plug its USB wires into a USB host You can also design your own hardware and use this programmed EPROM or FLASH to achieve the same purpose 5 1 Overview of Firmware Resources 5 1 1 USB Firmware Overhead To handle the USB protocol extra firmware needs to be included together with your application specific firmware The size of the USB firmware overhead depends on how complete and how many USB options are used At minimum the firmware needs to support all requirements of Chapter 9 of the USB Specification 1 0 If more commands such as HID device class more details on device class specifications are in Chapter 6 commands are supported the size of the firmware will increase accordingly Based on the sample code that is on the enclosed diskette the extra code required to support USB is approximately 1 to 2 Kbytes in size using the 8x930Ax 5 1 2 Application Specific Firmware Application
86. eState break DevicePowerState switch on Power Type 132 Appendices break IRP MN SET POWER case IRP MN QUERY POWER Look at what type of power query this is switch irpStack gt Parameters Power Type case SystemPowerState case DeviceSpecificPowerState TODO Your device may need to handle these loctls break SystemPowerState amp DeviceSpecificPowerState case DevicePowerState switch irpStack gt Parameters Power State DeviceState case PowerDeviceD2 break case PowerDeviceD1 break case PowerDeviceD3 break switch on Power State DeviceState break DevicePowerState switch on Power Type break IRP MN QUERY POWER case IRP MN QUERY STOP DEVICE break case IRP MN QUERY REMOVE DEVICE break case IRP MN CANCEL STOP DEVICE break case IRP MN CANCEL REMOVE DEVICE break default break 133 A WDM Driver Code Example nextStack IoGetNextIrpStackLocation Irp ASSERT nextStack NULL RtlCopyMemory nextStack irpStack sizeofIO_STACK LOCATION All PNP_POWER messages get passed to the PhysicalDeviceObject which in future revisions of this driver will be the StackDeviceObject we were given in PnPAddDevice This will be deviceExtension gt StackDeviceObject in future revisions of this driver ntStatus IoCallDriver deviceExtension gt PhysicalDeviceObject Irp If lower layer driver marked the Irp as pending then reflect that by calling I
87. eate this Im wndStatusBar SetIndicators indicators sizeof indicators sizeof UINT IEN TRACEO Failed to create status bar n return 1 fail to create TODO Remove this if you don t want tool tips or a resizable toolbar m_wndToolBar SetBarStyle m_wndToolBar GetBarStyle CBRS TOOLTIPS CBRS FLYBY CBRS SIZE DYNAMIC TODO Delete these three lines if you don t want the toolbar to be dockable 162 Appendices m wndToolBar EnableDocking CBRS ALIGN ANY EnableDocking CBRS ALIGN ANY DockControlBar amp m wndToolBar if peMenu GetMenu NULL pcSubMenu pcMenu gt GetSubMenu 0 DevName Format Test 0 hDrvrHnd CreateFile DevName GENERIC WRITE GENERIC READ FILE SHARE WRITE FILE SHARE READ NULL OPEN EXISTING 0 NULL enable the menu items if successful if hDrvrHnd INVALID HANDLE VALUE theApp hDrvrHnd hDrvrHnd theApp OnlnitTest peMenu gt EnableMenu tem 0 MF ENABLED MF BYPOSITION pcMenu gt EnableMenultem 1 MF ENABLED MF BYPOSITION pecMenu gt EnableMenu tem 2 MF ENABLED MF BYPOSITION peMenu gt EnableMenu tem 3 MF _ENABLED MF BYPOSITION pcMenu gt EnableMenu tem 4 MF ENABLED MF BYPOSITION DrawMenuBar return 0 163 An Application Software Code Example joes ae SSeS 2 BOOL CMainFrame PreCreateWindow CREATESTRUCT amp cs TODO Modify the Window class or styles here by
88. ect gt MajorFunction IRP MJ PNP POWER Test Dispatch pDriverObject gt DriverUnload Test Unload pDriverObject gt Driver Extension gt AddDevice Test PnPAddDevice return ntStatus 68 Step 5 Develop the USB Driver The DriverEntry routine dictates the initialization of the driver using pDriverObject gt MajorFunction IRP MLCREATE IRP_ MI CLOSE and pDriverObject gt DriverUnload For a WDM driver it also considers the IRP_MJ_ DEVICE CONTROL IRP_ MJ PNP POWER and the pDriverObject gt DriverExtension gt AddDevice The pDriverObject gt DriverExtension gt AddDevice is directed to the Test PnPAddDevice routine for this case where it creates the file handler to this device driver This is invoked when a USB device is plugged into a host PC Among other things the Test_PnPAddDevice routine creates a driver object using IoCreateDevice and sets up a symbolic link for the driver using IoCreateSymbolicLink The creation of the symbolic link enables user mode applications to open and operate on the driver object The IRP MJ PNP POWER has several MinorFunctions MN defined and it also provides for the Plug and Play and power management schemes for the devices For example one of the MinorFunctions IRP MN START DEVICE will get all the descriptors device configuration and string of the USB devices and set the configuration for each device The IRP MJ DEVICE CON
89. ected subsystem because each one resides in a separate process whose memory is protected from other processes by the Windows NT executive s virtual memory system These subsystems communicate by passing messages via the NT executive Each server or protected subsystem provides an API that programs can call When an application or another server calls an API routine a message is sent to the server that implements the API routine through the NT executive s local procedure call LPC facility The LPC is a message passing mechanism used by Windows NT The server replies by sending a message back to the caller There are two types of Windows NT protected subsystems environment subsystems and integral subsystems The environment subsystem provides an API specific to an operating system such as OS 2 POSIX or MS DOS as shown in Figure 6 4 The most important environment subsystem of Windows NT is the Win32 subsystem This subsystem makes the Microsoft s 32 bit Windows API available to application programs The Win32 environment also provides Windows NT s graphical user interface and controls all user input and application output The integral subsystems are servers that perform important 64 Step 5 Develop the USB Driver operating system tasks such as security subsystem networking subsystem etc D i MS DOS client Wind cet applications MS DOS other i subsystem subsystems servers Win32 user mode subsyst
90. ed by Win32 SDK Windows NT DDK and finally the USB DDK With all of these components in place you are now ready to develop the USB driver for your USB device The USB driver is developed in the Windows NT PC as shown in Figure 3 3 After its compiled into an executable format the driver is transferred to the host PC for code execution and debugs The host PC is required to operate a Windows 95 operating system either OEM Software Release 2 1 OSR 2 1 also codenamed Detroit or the Memphis operating system with the Microsoft Windows Driver Model WDM stack loaded The WDM stack can also be obtained from usbbeta microsoft com memreq microsoft com or the USB IF For driver development For driver execution and test M Windows 95 OS KE Windows 95 with WDM stack Windows NT DDK USB DDK Microsoft Visual C C Figure 3 3 Development environment host USB driver 34 Step 2 Set Up a Development Environment So in summary to develop a USB device driver two PCs are recommended one PC to develop the driver and the other to execute and debug the driver as shown in Figure 3 3 We can also use debugging software like SoftICETM to debug the driver that we have developed It is very important to know if the driver for the device is to be bundled with the operating system in the time frame we need If the driver is bundled together with the operating system you do not have to develop the driver yoursel
91. ely used to describe a communication system and is based on the seven layer OSI model Basically the entities in the same layer have a virtual connection or peer to peer communication between them The entities in the lower layer provide services to their next entities in the 27 USB Host higher layer In this fashion a PC application software designer for example does not have to worry about the physical connections of the devices The applications will work as long as the guidelines or specifications to use the services provided by the device layer are followed Host Device Interconnect Function Layer USB Device Layer USB Bus Interface Layer Actual Communications Flow demm Logical Communications Flow Figure 2 15 Inter layer communication model As shown in Figure 2 15 the lowest layer of the communication model is the USB Bus Interface layer It handles the physical connection between the host and the USB device On the host side this is the USB host controller hardware The next layer the USB Device Interface Layer uses the services provided by the USB Bus Interface layer to manage the data transfer between the host and the USB device This USB Device layer in the host has three basic components Host Software optional e USB Driver USBD Host Controller Driver HCD The HCD provide an interface for USBD to interact to the host controller hardware The interface between the USBD and the HCD
92. em Figure 6 4 Windows NT block diagram The NT Executive is the kernel mode portion of the Windows NT system It consists of the various components listed below Each of these components implements two sets of functions system services which environment subsystems and other executive components can call upon and internal routines which are only available to components within the NT executive The responsibilities of the executive components are e Object manager Creates manages and removes NT executive objects which represent the system resources e Security reference monitor Enforces security policies on local computers e Process manager Creates and terminates processes and threads e Local procedure call LPC facility Provides a mechanism to pass messages between a client process and a server process on the same computer e Virtual Memory VM manager Implements virtual memory a memory management scheme that provides a large private address space for each process e NT Kernel Provides operating system functions like interrupt response thread scheduling multi processors synchronization 65 Windows NT I O System Overview etc It also supplies a set of elemental objects and interfaces which the other NT executive uses I O system Consists of a group of components responsible for processing the inputs and outputs of a variety of devices It includes the following sub components gt HO manager i
93. enericHub Mfg Generic USB Hub USB CLASS_09 amp SUBCLASS_01 DeviceDesc Generic USB Hub USB CLASS_09 DeviceDesc Generic USB Hub PLX Mfg PLX Technology PCIVEN 10BS amp DEV 9060 DeviceDesc PLX USB Test Board VIA Mfg VIA Technologies PCIVEN 1106 amp DEV 3038 DeviceDesc VIA VT83C572 VT82C586 PCI to USB Universal Host Controller 76 Step 5 Develop the USB Driver After matching the idVendor and idProduct pair the driver uhcd sys will be loaded see the UniversalHCD Dev and the Universal HCD CopyFiles sections above Thus to ensure the proper loading of a driver device vendors should follow the following guidelines when defining the descriptor of their devices s Do not use the same values for the idVendor and idProduct pair for different devices The idVendor and idProduct pair is used to differentiate devices from one another e Use the bcdDevice values to differentiate revisions of what is essentially the same device to associate different versions of the driver If the device has multi configuration the bNumConfiguration from the device descriptor will also be used The white paper USB Plug and Play IDs and Selecting Device Drivers to Load located at http www microsoft com HWDEV busbios usbpnp htm also describes the drivers loading process 77 Step 6 Developing Host Application Software 7 Step 6 Developing Host Application Software The host application software provides a GUI to end u
94. erLength PDEVICE EXTENSION deviceExtension ULONG ioControlCode NTSTATUS ntStatus ULONG length PUCHARpch Get a pointer to the current location in the Irp This is where the function codes and parameters are located irpStack IoGetCurrentlipStackLocation Irp 153 A WDM Driver Code Example Irp gt IoStatus Status STATUS SUCCESS Irp gt IoStatus Information 0 Get a pointer to the device extension deviceExtension DeviceObject gt DeviceExtension ioBuffer Irp gt AssociatedIrp SystemBuffer inputBufferLength irpStack gt Parameters DeviceloControl InputBuffe rLength outputBufferLength irpStack gt Parameters DeviceloControl OutputBuffe rLength ioControlCode irpStack gt Parameters DeviceloControl IoControlCode Handle loctls from User mode switch ioControlCode case IRP Test GET PIPE INFO inputs none outputs we copy the interface information structure that we have stored in our device extension area to the output buffer which will be reflected to the user mode application by the IOS length 0 pch PUCHAR ioBuffer if deviceExtension gt Interface RtlCopyMemory pchtlength PUCHAR deviceExtension gt Interface deviceExtension gt Interface gt Length length deviceExtension gt Interface gt Length Irp gt IoStatus Information length Irp gt IoStatus Status STATUS SUCCESS break case IRP Test GET DEVICE DESCRIPTOR inputs p
95. erged together and the testing can continue A code example for the firmware to do a USB bus enumeration called USB ENUM ASM is on the enclosed diskette and listed in Appendix A This code is meant as a design example and it must be modified to suit the operation of the test device As shown in Figure 3 2 we use a separate USB host PC to send out USB packets to test and debug our firmware on the USB device The Contact Numbers section provides information on some of the USB ready PCs that can currently be purchased from your local computer stores These PCs can then be configured to be the USB host system for testing purposes One software tool you ll need is the Single Step Transaction Debugger SSTD that can be used in the host This SSTD allows us to send a single USB packet through the USB wires to test our firmware in the evaluation board In this manner we can test the operation of our code when it receives a single USB packet A bus analyzer is also included in the development environment as shown in Figure 3 2 It is used to capture and display all the USB traffic on the USB wires that the analyzer taps into This is useful for testing and debugging purposes because it allows you to visualize what is actually happening on the USB wires This is a third party tool and the contact information is listed in the Contact Numbers section In some cases designers may choose to use a USB in circuit emulator ICE to help test and debug the
96. erstanding of their operations USB functions generic SFRs EPCONFIG FADDR SOFH SOFL PCON1 IEN1 IPL1 and IPH1 Endpoint specified SFRs EPCON TXCNTH Affected by EPINDEX RXDAT RXCNTL TXDAT TXCNTL RXFLG RXCNTH TXFLG TXCON RXSTAT RXCON TXSTAT Endpoint specified SFRs Not FIE FIEI FIFLG AND FIFLG1 affected by EPINDEX 4 2 Interface with the 8x930Ax The interface of the 8x930Ax to USB is simple the USB module even has a transceiver integrated You only need to connect series resistors of 27 to 33 Q to the D o and Dean pins and to connect a resistor of 1 5 kQ to the Da corresponding to the D line of the USB wires as shown in Figure 4 5 The connection of the pull up 1 5 kQ resistor is to configure the 8x930Ax for a full speed device If you use the 8x930Ax as a low speed USB device the 1 5 kQ pull up resistor is required to connect to the Dan corresponding to the D line of the USB wires instead The Evaluation Kit see Chapter 3 for more details provides a schematic of the evaluation board and it can be used as a reference 3 0 3 6 v 1 5k to USB wires serial port USB modile Dy 27 33 Q S bit data bus 8x930Ax port pins 5 PC A channels Figure 4 5 Interfaces of the 8x930Ax To interface the 8x930Ax on the other side of USB use the general purpose I O ports the external memory bus the PCA or the serial port as shown in Figure 4 5 The 8x930Ax has 256 Kbytes of addressibility that can b
97. es The application software and WDM driver examples run on the host PC To get a copy of the Memphis Developer Release operating system contact Microsoft or the USB IF On the other side of the USB wires use the enclosed firmware example and the Intel 8x930Ax evaluation board as the USB device Note The code examples included here are not production worthy and are meant to depict some concepts highlighted in the book Users are required to modify the application software device driver and firmware to suit their requirements and to make the programs more robust as well as to adhere to specifications The code examples are provided as is without warranty of any kind either expressed or implied including but not limited to the implied warranties of merchantability and or fitness for a particular purpose 89 Content Description of the Enclosed Diskette 8 1 Content Description of the Enclosed Diskette There are several files included in the enclosed diskette test rom ihx A hex file in Intel hex format It is assembled using a PLC 3 06 for the USB device to perform assembler The corresponding enumeration and handle some project file is test rom Dro control transfer functions It is Other assemblers can also be ready to be programmed into a used but users may need to do 32 Kbyte EPROM This minor modifications to the EPROM is then plugged into asm file the 8x930Ax evaluation board which will then behave as a USB device The corr
98. es and at least one thread of execution A thread is an executable unit within an NT process The operating system executes one thread for a short time and then switches to another thread running each thread in turn This gives the multitasking illusion of the operating system to the users The Windows NT design was based on the combination of three models Client server and layered model It uses the client server model to provide multiple operating environments to its users e g Windows MS DOS OS 2 and POSIX Based on this model the operating system is divided into several processes each of which implements a single set of services Each server runs in user mode executing a loop that checks if a client has requested its service The client which can be either another operating system or an application program requests a service by sending a message to the server An operating system running in a kernel mode delivers the message to the server After the server performs the operation the kernel returns the results to the client in another message as shown in Figure 6 3 The operating system code runs in a privileged mode referred to as kernel mode and has access to the system data and hardware The applications however run in a non privileged mode referred to as user mode with a limited set of interfaces and limited access to system data When a user mode program calls a system service the processor traps the call and t
99. es the ISR i e after the RETI instruction the previous value of the program counter is restored Our program execution will return back to where the interrupt occurred between FF 0200H and FF 0500H in our example 41 Overview of the 8x930Ax USB Microcontroller The 8x930Ax has 11 interrupt sources 10 maskable and a TRAP instruction The maskable sources are e 2 external interrupts e 1 PCA interrupt e I serial port interrupt 3 timer interrupts 3 USB interrupts The TRAP interrupt is intended for tools development only All the maskable interrupts have interrupt request flags associated with them Some of these flags tell us the exact source of the interrupt Let us take the serial port interrupt for example When a serial port interrupt occurs at ISR vector address of FF 0023H our firmware is required to check the RI or TI flags of SCON special function register SFR whether the interrupt is caused by a reception RI flagged or transmission TI flagged of the serial port All of these maskable interrupts have four user selectable priorities and can be individually enabled disabled There is also one global enable bit EA bit in the IENO SFR to enable or disable all of the maskable interrupts There are three interrupt sources associate with the USB module of the 8x930Ax e one for the transmit and receive interrupts associated with each endpoint pair one for the start of frame SOF interrupt and
100. esign example and its source codes By studying the code examples provided on the enclosed diskette designers can get a good insight into the requirements of developing the firmware codes drivers and application software This book and the code examples can easily cut weeks of development time off your USB device design effort 1 1 What is USB Anyway Lots of PC users have had bad experiences installing PC peripherals We connect external devices to our PC but before long we run out of serial or parallel ports Once we start to open the PC box to install expansion cards add in cards etc things become even more complicated We face a complex and astonishing number of dip switches jumper cables software drivers IRQ settings and I O addresses that must be configured We are typically required to go through hundreds of pages of the installation guides just to install our peripherals successfully Sometimes we even need to call the dreaded Please hold for the next available representative technical hot lines to get things straightened out The era has finally arrived to forget about all the troubles of installing new PC devices This is the era of the Universal Serial Bus USB The USB Specification Rev 1 0 was finally released to the world on January 15 1996 royalty free The spec is a joint collaboration among seven leading computer telecommunications and software companies Compaq Digital Equipment Corporation IBM PC Comp
101. esponding firmware source code file in assembly language format is usb_enum asm located in the device directory testdrv sys A WDM driver for the USB It is built using the Microsoft device to be loaded onto the lNT DDK USB DDK and host The corresponding source Visual C C compiler It can files in C C format and be built under Free Build or header files are located in the Checked Build Environment host driver directory This after the DDK is installed The driver is ready to be loadedl file titled sources in the using the corresponding test inf host driver directory defines file in the floppy s root directory the source files components libraries and compilation environment test app exe An executable application It is compiled using Microsoft software for the USB host PC Its Visual C C and Developer corresponding source files in Studio with the project work C C format and header files space file test_app mdp The are located in the Vhostlapp test app mdp defines all the directory The test app exe is required files and resources compiled with dynamic link library whereas the test_app exe compressed in the test_app zip is compiled with static library 90 USB Application Software WDM Driver and Firmware Examples 8 2 Setting Up the Demonstration After completing the lab setup as described in the previous sections it is fairly easy to demonstrate and use the application software WDM driver a
102. ess 00H 127 Only after this status stage will the device be required to change its address to 02H as indicated by the SET ADDRESS command The host will use this new assigned address to communicate with our device in subsequent transactions For example in packet 4180 the ADDR of the setup packets is 02H 128 Syne 00000001 SOF OxAS Frame Ox4FA CRCS OxiF Standard SOF packets appearing every 1 ms are issued in this gap After the SET ADDRESS command the host follows with a GET DESCRIPTOR device command as shown in packet 181 The second byte of the data 06H indicates a GET DESCRIPTOR command and the 3rd and 4th bytes showing 0001H indicate that the descriptor type is device Syne 00000001 SOF OxAS Frame Ge CROS Ox1A Sync 00000001 SOF 0xA5 Frame 0x52D CRCS 0x05 Sync 00000001 SETUP DxB4 ADDR 0x02 ENDP 0x0 CROS 0x15 81 Sync 00000001 DATA0 GxC3 DATA 80 06 00 01 00 00 80 00 CRC16 0xB129 82 Synct_0000001 ACK Ox4B The host then issues a series of IN tokens to attain descriptor information from our device This is shown in packets 184 189 and 194 The device responds accordingly and a total of 18 bytes are sent to the host as required bv the USB Specification 183 Sync 00000001 SOF OxA5 Frame 0x52E CRC5 0x07 184 Sync 00000001 IN 0x86 ADDR 0x02 ENDP 0x0 CRC5 0x15 185 j Sync 000001 DATA1 0xD2 DATA 12 01 00 01 00 00 00 08 CRC16 0xC8E7 24 Step 1 Understand th
103. f All that you are required to do is to follow the USB device class specifications when you design the device Details about device class specifications will be discussed in Chapter 6 On the host applications side we can use Microsoft Visual C Developer Studio AppWizard to create the applications Chapter 7 will discuss the development of the application in greater detail 3 3 Contact Numbers Description Intel USB930EVALKIT 8x930Ax Evaluation Kit and Adapter Card Apbuilder evaluation copy software hardware and software Intel Apbuilder software can also be obtained from software Single Step Transaction Debugger SSTD software USB host commercially available as of publication date e IBM model 2176C6Y or higher Toshiba model name Infinia Sony model PCV70 VAIO Compaq model number 4762 or higher Siemens model Scenic Pro C5 PC hardware CATC USB Detective bus analyzer USB Traffic Generator USB Host Production Tester hardware Microsoft Software Developer Network MSDN Information Contact Numbers http www intel inte ma US 800 628 8686 UK 44 01793 431155 Israel 972 03 548 3200 Apac 852 2844 4555 Japan 81 298478511 inte com design usb com design usb nual for the manual com design BUILDER apbldr intel SWSUP com design usb pc ibm com aptiva toshiba com US 800 638 2423 408 727 6600 Europe 46 40 59 2200 Apac 886 02 278 1938 Japa
104. f the adjacent window you can see the Menu Item Properties windows As shown in Figure 7 5 an ID has already been defined by AppWizard to be the ID APP ABOUT for this case This ID APP ABOUT ID is used in the application routine ON COMMAND ID APP ABOUT OnAppAbout of the BEGIN MESSAGE MAP routine in the test cpp file as shown in Figure 7 6 83 Linking the Application Software to the WDM driver e Mis ut Desebaper Stiti 1651 Irch eet E mj Eile Ede ew eet Esia Tools Window Help GEG Belk TEESE static ar THIS_FIIE FILE tendit AERE APE E ee ee DEE ENEE RADAR a PAA EEE AEE pe f Sleatapp BEGIM MESSAGE MAP CT et pp CHindpp Ap pb ist Z MOTE art vili add and cama doping lahtist Ke Di HOT SRT Zant You cee in thee Tacks of generac o LES MEG MAP on Stoddard Si Le based dogiuagtnt commas COMMARD ID FILE HEN C indpp OnFi Leen 2 Gd We SE EE Gab i eOpes ards on EE e AA rep CVin pp OoFilePrintS tup END_HESSAGE NAF i PERE LEAL ADB DEL OEE APE EEE Ea OEE IEEE ER AAP daa Ae EBD OEE ze NGE Figure 7 6 ID APP ABOUT in the BEGIN MESSAGE MAP routine With this definition done the OnAppAbout routine as depicted in Figure 7 7 will be invoked when the About test menu item of the application software is selected Similarly other menu functions and their corresponding IDs can be defined this way to provide additional functionalities to the application software A more detailed
105. g 0000001 SOF OxA5 Frame 0x132 CRC5 0x17 194 Syne 00000001 IN Ox86 ADDR 0x03 ENDP 0x0 RC5 0x08 Sync 00000001 DATA1 0xD2 DATA 00 01 CRC16 0xFCF1 196 Syna 00000001 ACK 0x48 197 Sync 00000001 SOF OxA5 Frame 0x133 CRC5 0x08 start of status stage RER Synct00000001 SOF OxAS Frome MOxts4 CROSIOXIG W Syne 00000001 OUT 0x87 ADDR 0x08 ENDP 0x0 CRC5 0x08 200 Sync 00000001 DATA 0xD2 DATA CRCT6 Ox0000 201 Sync O0000001 ACK Ox4B SSCS 202 Sync 00000001 SOF 0xA5 Frame 0x135 CRCS 0x09 Syne 0000D001 SOF OxA5 Frame M0x136 CRC5 0x0B Figure 2 13 An example of control transfer In the beginning there is no activity in the bus and the host sends out the 1 ms interval SOF packets as shown in packet 178 of Figure 2 13 Note that the time interval between any two SOF packets is 1 ms for example there is an I ms period between packet 178 and packet 179 As shown above each USB frame of ms between SOFs is boxed together to display the single frames In the 1 ms period starting by the packet 179 the host sends out a SETUP token packet 180 and 8 bytes of setup data packet 181 to a device These eight bytes of data specify what type of request the host wants from the device The first byte specifies the characteristic of the request For this case it is 80H which means that the direction of the subsequent packets will be from device to host the request ty
106. h PUCHAR pch Get a pointer to the current location in the Irp irpStack loGetCurrentlrpStackLocation Irp Irp gt IoStatus Status STATUS SUCCESS Irp gt IoStatus Information 0 Get a pointer to the device extension deviceExtension DeviceObject gt DeviceExtension ioBuffer Irp gt Associatedlrp SystemBuffer inputBufferLength irpStack gt Parameters DeviceloControl InputBufferLength outputBufferLength irpStack gt Parameters DeviceloControl OutputBufferLength ioControlCode irpStack gt Parameters DevicehControl IoControlCode switch ioControlCode other cases case IRP_Test GET CONFIGURA TION_DESCRIPTOR length Test GetConfigDescriptor DeviceObject ioBuffer outputBufferLength Irp gt loStatus Information length Irp gt loStatus Status STATUS SUCCESS break other cases default Irp gt IoStatus Status STATUS INVALID PARAMETER ntStatus Irp gt IoStatus Status hCompleteRequest Irp IO_NO_INCREMENT return ntStatus 70 Step 5 Develop the USB Driver s example of a URB ULONG Test GetConfigDescriptor IN P DEVICE_OBJECTDeviceObject PVOID pvOutputBuffer ULONG ul Length s t PDEVICEj XTENSION device Extension NULL NTSTATUS ntStatus STATUS_SUCC ESS PURB urb NULL ULONG length 0 deviceExtension DeviceObject gt DeviceExtension urb ExAlhcatePool NonPagedPool sizeof struct URB CONTROL_DESCRIPTOR_REQUEST if
107. h is shorter The amount asked for or the amount available push ACC push B clr CY A Actual wLength AskedFor subb A wLength 1 mov A B subb A wLength je AskedFor_IsLarger LengthsMatch wLengthlsSmaller If Asked for is smaller replace actual with asked for pop B pop ACC mov B wLength mov A wLength 1 ljmp Loadlt AskedFo IsLarger pop B pop ACC Loadlt from now on wLength bytes remaining mov ControlBuffBytesLeft B mov ControlBuffBytesLeft 1 A Call LoadControlTXFifo ljmp ReturnSTDGetDeviceCommand CheckGetConfiguration cjne A HGET CONFIGURATION CheckGetStatus GET CONFIGURATION ljmp ReturnSTDGetDeviceCommand CheckGetStatus 117 Firmware Code Example For Intel 8x930Ax USB Microcontroller cjne A GET STATUS ReturnSTDGetDeviceCommand GET DEVICE STATUS ljmp ReturnSTDGetDeviceCommand ReturnBADSTDGetDeviceCommand push EPINDEX mov EPINDEX 401 mov TXDAT 12h mov TXCNT 01h pop EPINDEX orl EPCONO 40C0h Stall EPO RetumSTDGetDeviceCommand ret Standard Get Endpoint Commands StandardGetEndpointCommand mov A bRequest cjne A GET_STATUS ReturnBadSTDGetEPCommand GET ENDPOINT STATUS mov A wIndex I anl A 0Fh Mask off all but the endpoint value orl EPINDEX A Point the Index register at the mov A wIndex 1 Start by clearing out RO jb ACC 7 GetlnStallStatus GetOutStallStatus mov A EPCONO jnb ACC 6 NotStalled mov A 01 Return Stalled jmp D
108. hat belongs to one and only one process It consists of a program counter a user mode stack a kernel mode stack and a set of register values All threads in a process have equal access to the process s address space object handles and other resources Threads are implemented as objects 105 Glossary Thread Scheduling Time out Token packet Transaction Transfer Type UART Universal Serial Bus Software Upstream USB USBD User Mode The process of examining the queue of threads that are ready to execute and selecting one to run next performed by NT executives The detection of a lack of bus activity for some predetermined interval A type of packet that identifies what transaction is to be performed on the bus The delivery of service to an endpoint consists of a token packet optional data packet and optional handshake packet Specific packets are allowed required based on the transaction type Determines the characteristics of the data flow between a software client and its function Four Transfer types are defined control interrupt bulk and isochronous Universal Asynchronous Receiver and Transmitter An on chip industrial standard MCS 51 type 4 mode two wire serial port of the 8x930Ax microcontroller Includes hubs and functions See Device The hardware interface between the Universal Serial Bus cable and a Universal Serial Bus device This includes the protocol engine required for all
109. he device object for this instance of the Test Device Return Value NT status code PDEVICE EXTENSION deviceExtension NTSTATUS ntStatus PURB urb NULL ULONG siz PUSB_CONFIGURATION DESCRIPTOR configurationDescriptor NULL deviceExtension DeviceObject gt DeviceExtension Get memory for the USB Request Block urb urb ExAllocatEPO0ol NonPagedPool sizeof struct URB Control DESCRIPTOR REQUEST if urb NULL I Set size of the data buffer Note we add padding to cover hardware faults that may cause the device to go past the end of the data buffer siz sizeof USB CONFIGURATION DESCRIPTOR 16 144 Appendices Get the nonpaged pool memory for the data buffer configurationDescriptor ExAllocatepool NonPagedPool siz if configurationDescriptor NULL UsbBuildGetDescriptorRequest urb USHORT sizeof struct _URB control DESCRIPTOR REQUEST USB CONFIGURATION DESCRIPTOR TYPE 0 0 configurationDescriptor NULL sizeof USB_CONFIGURATION_DESCRIPTOR Get only the configuration descriptor NULL ntStatus Test_CallUSBD DeviceObject urb else ntStatus STATUS NO MEMORY goto Exit_TestConfigureDevice if else Free up the data buffer memory just used ExFreepool configurationDescriptor configurationDescriptor NULL Determine how much data is in the entire configuration descriptor and add extra room to protect against accidental overrun siz config
110. hen switches the calling thread to kernel mode When the system service completes the operating system switches the thread back to user mode 62 Step 5 Develop the USB Driver memory server other servers send Client Application file server user mode kernel mode NT executive Figure 6 3 A client server operating system The client server approach results in a more robust operating system This is because each server runs in a separate user mode process a single server can fail and be restarted without crashing or corrupting the rest of the operating system In simple terms users only need to end task kill the application that hangs and continue with their work in other applications on Windows NT systems In some other operating systems users typically need to reboot the entire system if one application hangs The Windows NT operating system model is also based on a layered model in its executive I O system as well as in the lowest portion of NT executive the NT kernel and the hardware abstraction layer HAL The kernel mode of Windows NT is called the NT executive It consists of various components that implement virtual memory management object resource management I O and file systems inter process communication and portions of the security system All other components of the Windows NT executive are layered on the NT kernel and HAL components The NT kernel performs low level operating s
111. ibing device gDevice bNumConfigurations db 1 END DEVICE DESCRIPTOR J Initialize global Config descriptor BEGIN CONFIG DESCRIPTOR gConfig bLength db 09h gConfig bDescriptorType db CONFIG DESCR gConfig bTotaiLength db END CONFIG DESCRIPTOR BEGIN CONFIG DESCRIPTOR gConfig bCorrection db 0 gConfig bNumInterfaces dbl NUM OF INTERFACES gConfig bConfigurationValue db 2 gConfig iConflguration db 0 gConfig bm ttributes db 040h gConfig MaxPower db 025 50ma Initialize global Interface descriptor soenrorvrrrnre E BEGIN INTERFACE DESCRIPTOR ginterface bLength db END INTERFACE DESCRIPTOR BEGIN JNTERFACE DESCRIPTOR ginterface bDescriptorType db INTERFACE DESCR ginterface bInterfaceNumber db 0 gInterface_bAlternateSetting db 0 gInterface_bNumEndpoints db Olh gInterface_bInterfaceClass db 00h gInterface_bInterfaceSubClass db 00h gInterface_bInterfaceProtocol db 00h glnterface_ilnterface db 0 126 Appendices END INTERFACE DESCRIPTOR END CONFIG DESCRIPTOR STRING LOC TABLE STRING 1 db LOW STRING 2 STRING 1 db STRING DESCR db USB Test Firmware STRING 2 RAM MEMORY MAP Control variables need to be placed between 20h amp 7fh for the addressing mode If RISM is running RISM needs 20h 3fH so be careful running RISM i DEFINE OUR DATA SEG SPACE DATA SEGMENT OUR DATA SEG Buffer and associated variables for Control Endpoint
112. iew port where we can manage the document The document class is responsible for controlling all the data 79 Develop Application Software using App Wizard MFC DLL AppWizard Used to create DLLs that use the Microsoft Foundation Classes MFC library Three types of DLL projects are supported regular DLLs that use static linking to MFC regular DLLs dynamically linked to MFC and extension DLLs that are always dynamically linked to MFC Custom AppWizard Used to create customized AppWizards from scratch based on an existing AppWizard type or based on an existing project Class Wizard Used to define the classes used in a program created with AppWizard You can add classes and functions that control how messages received by each class are handled It also helps to manage controls that are contained in dialog boxes OLE Object Linking and Embedding ControlWizard Used to create the basic framework of an OLE control An OLE control is a customized control that supports a defined set of interfaces and is used as a reusable component OLE controls replace the Visual Basic Controls of VBXs that were used in the 16 bit version of the Windows operating system 7 2 Develop Application Software using AppWizard In this section we describe a way to build a skeleton of the application software using the AppWizard portion of the Microsoft Developer Studio After the installation of Microsoft Visual C and the Developer Studio activate th
113. ion when designing the hardware and the firmware of the device For example most keyboards available today in the market work with the device driver provided by Windows 95 You are not required to install any device drivers using a diskette from the keyboard manufacturers The same scenario applies to USB keyboards For example if the keyboard driver is provided by the Windows 95 operating system and you follow the keyboard specification when designing your keyboard you do not have to provide any device drivers to end users In Chapter 6 we describe in greater detail how to go about designing a device driver You only need to develop the device driver if the required driver is not bundled with the Windows operating systems you are designing for or if the device does not follow the device class specifications You may wish to differentiate your products by adding extra features that are not supported or included in the generic device drivers 5 3 The 8x930Ax Operating Model To help you understand the operation of the USB firmware an operating model of a typical USB device is explained in this section The model is shown in Figure 5 1 50 Step 4 Develop the Device Firmware chip NY reset N p SE aw Initialize ar ae Un enu merated ee e kl return Interrupt Other J be e interrupt occurs SE E eg E ISR Setup ISR I J La vn wc e
114. ir 0 as control transfer endpoints It is used to exchange information see enumeration section under USB Functions when the device is first 11 USB Transfer Types attached to the host USB ensures that the control transfer is delivered without error This is done using CRC error checking see section USB Packet Formats and re transmission if the error cannot be recovered 2 Isochronous Transfer Isochronous transfer can be uni directional or bi directional It is intended to be used to transfer information that requires a constant rate and can tolerate errors A good application example of this transfer type is 64 kbps Pulse Code Modulation PCM voice data The voice data requires a constant rate and can tolerate errors typically up to a bit error rate of Ix103 Isochronous transfer has the following characteristics guaranteed access to USB with bounded latency and noretrying in case of a delivery failure due to error The maximum packet size for isochronous transfer is 1023 bytes per USB frame of 1 ms This implies that the maximum transfer achievable using isochronous transfer is 8 184 Mbps 3 Interrupt Interrupt transfer is uni directional and only inputs to the host It is used to support data transfers that are small in size and happen infrequently The interrupt transfer of USB is of a polling type that is the host asks if the interrupt endpoints have any data to send according to the frequency requested by
115. irs defualt or six endpoint pairs EPINDEX Endpoint Index Register To select the appropriate endpoint FADDR Function Address Register To store the address for the device after receiving the SET ADDRESS command from the host during device enumeration Its default value is OOH as required by the USB Specification FIE USB Function Interrupt Enable To enable or disable the receive and transmit done for the 4 endpoint pairs USB Function Interrupt Enable 1 To enable or disable the receive and transmit done for endpoint pairs four and five if selected see EPCONFIG FIFLG USB Function Interrupt Flag Register To store the transmit and receive done interrupt flags when the endpoints are configured as non isochronous endpoints for the four endpoint pairs FIFLG1 USB Function Interrupt Flag 1 To store the transmit and receive done interrupt flags when the endpoints are configured as non isocronous endpoints for endpoint pairs five and six if selected see EPCONFIG IEN1 Interrupt Enable Register 1 To enable individual programmable interrupts for the USB interrupts IPL1 Interrupt Priority Low Register 1 To establish relative priority for programmable interrupt It is used in conjunction with IPH1 46 Step 3 Developing The Device Hardware EE Interrupt Priority High Register 1 To establish relative priority for programmable interrupts It is used in conjunction with IPL1 PCON1 To store the USB suspend re
116. is known as the Host Controller Driver Interface The Microsoft Windows 95 operating system supports Open Host Controller Interface OHCI and Universal Host Controller Interface UHCI The USBD in turn provides services to the Client Layer The Client Layer describes all of 28 Step 1 Understand the USB Specification the software entities that are responsible for directly interacting with their USB devices Certain device classes of USBD s are provided with the operating system If the driver required by a device is not provided by the operating system a custom driver needs to be developed Chapter 6 describes the development process of USB drivers 29 Step 2 Set Up a Development Environment 3 Step 2 Set Up a Development Environment With a basic understanding of the USB Specification you are now ready to design a USB device For the purpose of this book and because of the flexibility and compliance to the USB Specification this book examines using the Intel 8x930Ax USB microcontroller to design a USB device The 8x930Ax is the first general purpose USB microcontroller available Let us first re examine at the steps required to develop a USB device as mentioned in Chapter 1 Figure 3 1 summarizes the tasks needed to develop a USB device Step 3 to step 6 can be taken in parallel if you have a tight schedule and if your resources permit Typically for a simple USB device a minimum of two designers are required one to f
117. is included on the enclosed diskette and listed in Appendix A for your reference It enables the 8x930Ax to perform the USB enumeration when a device first attaches to the host Since the enumeration is mandatory the code example can be re used It should be modified and integrated with other firmware modules to complete the firmware for your device In this section the operating model of the enumeration code is explained It can be used as an example for handling USB control transfers described in earlier sections initialize SFRs variables etc idle_loop user applications Figure 5 5 Flow diagram of the enclosed USB_ENUM ASM 56 Step 4 Develop the Device Firmware SET commands SetupS lt tlommand data stage YES RET SetupGetCommand S 5 g 7 F 4 d i SE GO Ge g 3 gear a 233 5 55 ist I z i II Si SU S S P ER S 5E 3 S SE 2 Tee AE A ANE EN si E HF 5 Figure 5 6 Flow diagram of the USB_ENUM ASM Figure 5 5 and Figure 5 6 show the flow diagrams of the enumeration code USB_ENUM ASM The complete listing of the code is in Appendix A This USB ENUM ASM is ready to be assembled and programmed 57 USB Enumeration Code into a 32 Kbyte Flash or EPROM It was tested with the PLC assembler see Chapter 3 for details and you may need to make minor modifications for other assemblers The code starts with the initialization of SFRs
118. lication Software Code Example RUNTIME CLASS CUsbappView AddDocTemplate pDocTemplate Parse command line for standard shell commands DDE file open CCommandLinelnfo cmdlnfo ParseCommandLine cmdlInfo Dispatch commands specified on the command line if ProcessShellCommand cmdInfo return FALSE return TRUE CAboutDlg dialog USBD for App About class CAboutDlg public CDialog publi c CAboutDlg Q Dialog Data AFX_DATA CAboutDlg enum IDD IDD ABOUTBOX R AFX DATA ClassWizard generated virtual function overrides AFX_VIRTUAL CAboutDlg protected virtual void DoDataExchange CDataExchange pDX DDX DDV support AFX VIRTUAL Implementation protected AFX_MSG CAboutDlg No message handlers NYVAFX MSG DECLARE MESSAGE MAP B CAboutDIg CAboutDlg CDialog CAboutDlg IDD 168 Appendices AFX_DATA INIT CAboutDlg AFX_DATA_INIT void CAboutDlg DoDataExchange CDataExchange pDX CDialog DoDataExchange pDX AFX DATA MAP CAboutDig NVAFX DATA MAP BEGIN MESSAGE MAP CAboutDlg CDialog AFX_ MSG MAP CAboutDlg No message handlers N AFX MSG MAP END MESSAGE MAP App command to run the dialog void CUsbappApp OnAppAbout d CAboutDlg aboutDlg aboutDlg DoModal CUsbappApp commands int CUsbappApp ExitInstance TODO Add your specialized code here and or call the base class CloseHandle hDrv
119. lossary of execution some portion of the user s resource quotas and the system resources that the operating system has allocated to the process s threads A specific set of rules procedures or conventions relating to format and timing of data transmission between two devices A request made to a Universal Serial Bus device contained within the data portion of a SETUP packet A Universal Serial Bus hub directly attached to the host controller This hub is attached to the host tier 0 The upstream port on a hub Small Computer Systems Interface A local I O bus that allows peripherals to be attached to a host using generic system hardware and software Special Function Registers Registers used by microcontrollers for our case the 8x930Ax as control panels and status indicators to its firmware Start of Frame The SOF is the first transaction in each frame SOF allows endpoints to identify the start of frame and synchronize internal endpoint clocks to the host One part of the sequence composing a control transfer 1 e the setup stage the data stage and the status stage Type A classification that characterizes an isochronous endpoint s capability to connect to other isochronous endpoints Time Division Multiplexing A method of transmitting multiple signals data voice and or video simultaneously over one communications medium by interleaving a piece of each signal one after another An executable unit t
120. mplements input output facilities and establishes a model for the NT executive I O gt File systems gt Network re director and network server gt NT executive device driver which directly manipulates hardware gt Cache manager e Hardware abstraction layer HAL A layer of code between the NT executive and the hardware platform on which Windows NT is running Developing a USB driver requires focusing on the I O System of the Windows NT operating system 6 4 Windows NT UO System Overview The NT executive s I O system is a collection of operating system codes that accept I O requests from the user or kernel mode processes and delivers them to I O devices In the context of USB the I O system can be considered an interface between system processes and USB devices Figure 6 5 depicts a simplified view of the Windows NT I O system structure Every I O request is represented by an I O request packet IRP which travels from one I O system component to another An IRP is a data structure that controls how the I O operation is processed at each stage along the way The I O manager as shown in Figure 6 5 defines an orderly framework within which I O requests are delivered to file systems and device drivers The I O manager creates an IRP that represents each I O operation passes the IRP to the correct drivers and disposes of the packet when the I O operation is completed A driver on the other hand receives the IRP and performs
121. n 1 Suspend and resume signaling are used to reduce power consumption of bus powered USB devices as the overall power supply is limited in a USB system The bus powered devices must go into a suspend mode when they see a constant idle state on the USB wires for more than 3 ms Any bus activity including the SOF packets will keep the devices from going into suspend mode In the suspend mode the devices must draw less than 500 uA from the bus see Section 7 1 4 4 of the USB Specification Once the device is in this mode its operation can be resumed by receiving a non idle signaling from the host The device can also signal the system to resume operation if it has the remote wakeup capability see section 7 1 4 5 of USB Specification Note that the remote wakeup is considered to be an exceptional event in the USB protocol because it is initiated by devices with the remote wakeup capability configured The host initiates all other activities in a USB system 2 11 USB Host The basic flow and interrelationships of the USB communications model are shown in Figure 2 15 The model is divided into three layers Function USB Device and USB Bus Interface Layers Black arrows indicate the actual communication flow All communications between the host and the device ultimately occur on the USB bus interface layer However there are logical host device interfaces between each horizontal layer shown with the gray arrows This layering concept is wid
122. n 81 332451351 US 800 759 5474 fax US 206 936 2490 msdn microsoft com catc com microsoft com msdn To get beta copy of Microsoft WDM USB DDK usbbela microsoft com memreq microsoft com 35 Contact Numbers Contact Numbers http www SoftICE debugger for USB driver Win 95 TASKING C Toolset 251 930 assembler compiler and debugger software Keil Software DK 251 assembler compiler and debugger software Production Languages Corporation PLC COMPASS 251 assembler compiler and debugger software SystemSoft 8x930 Success Program Turnkey solutions on USB device drivers software Phoenix Technologies System Essentials Utility class device driver firmware American Megatrends Inc AMIBIOS 95 USB BIOS USB capability Metalink RVM 930 emulator or EM 930 8x930x ROM emulator hardware emulator Nohau EMUL251 POD930 8x930Ax In Circuit Emulator hardware emulator iSYSTEMS iC2000 PowerEmulator hardware emulator US 603 889 2386 US 61 7 320 9400 Europe 31 33 55 8584 US 800 348 8051 Europe 49 8946 5057 Apac 657492162 US 800 525 6289 Europe 81 7 599 8363 US 805 486 6686 Taiwan 545 5370 US 408 654 9000 Eur 44 1483 243200 Apac 88627188956 Japan 81 3 3374 6555 US 770 246 8600 US 602 926 0797 Europe 49 8091 56960 Korea 82 2 517 3707 US 408 866 1820 Europe 46 40 922425 Korea 82 2 784 7841 Japan 81 0334050511 US 207 236
123. nd firmware examples First program the Intel hex file test_rom ihx into a 32 Kbyte EPROM and then plug it into the 8x930Ax evaluation board replacing the ROM device that is on the evaluation board Note the settings of various dip switches of the board especially the EA page non page and binary source mode switches The EA pin of the 8x930Ax microcontroller needs to be enabled pulled low so that the 8x930Ax executes its code from external memory The page non page dip switch needs to be set to correspond to the setting for the external memory bus of the evaluation board The binary source mode dip switch must be set to binary mode for this example For the purpose of this demonstration set the dip switches of the evaluation board to ON xl x OFF LL Is KR AA AA AE DDDDDDDA 108 amp amp TT 2161 0 CE Please refer to the 8x930Ax Evaluation Board User s Manual see Section 3 3 for how to obtain manual for detailed descriptions of the board After setting up and powering up the evaluation board it is ready to be used as a USB device The LED that is connected to port pin p1 0 will blink to indicate that the board is operational At this point connect the evaluation board to the USB host using a USB cable This should activate the enumeration process and on the host PC an Update Device Driver Wizard Unknown Device screen will pop up as shown in Figure 8 2 At this point the host has performed the
124. ndshake indicates that there is an error condition on the device and it requires host software intervention Note that the NAK and STALL handshake packets are only sent out by the device 20 Step 1 Understand the USB Specification 2 9 4 Interrupt Transfer Interrupt transfer is similar to the bulk transfer except it consists solely of IN tokens in its token phase Upon receiving the IN token the device may return data or a NAK or STALL packet If the device has no new interrupt data to return it returns a NAK handshake in the data phase If the device is stalled and requires host software intervention it returns a STALL handshake If an interrupt is pending the function returns the interrupt information as a data packet Upon receiving the data packet the host returns an ACK handshake if the data was received error free or it returns no handshake if the data packet was corrupted As mentioned only devices are allowed to return NACK packets as a handshake the USB host returns an ACK packet or returns no packet at all 2 10 USB Functions All USB devices hub or hubless are required to have a default address of 000 OOOOB upon powering up They are also required to have their endpoint 0 configured as the control endpoint pair transmit and receive pair 2 10 1 USB Enumeration Steps When a USB device is attached to the bus the host uses a process known as bus enumeration to identify and manage the newly attached device This p
125. ne place Do I need to develop a device driver for my USB device Will USB get rid of the PC add in cards Wow if I don t need the add in cards for my devices I can reduce the cost by Can our current RS 232 device use the benefits of USB How many engineers or computer scientists do I need to design a USB device Where can I find a summary of USB protocol The spec is over 250 pages Do I need to attend a class to understand USB Device Driver Class Where do I get more info to develop my USB device This book is written with the aim of answering these questions It is intended for USB device project managers USB design engineers USB device marketing staff or USB sales personnel It is also meant for those who are interested in USB who would like to know more about USB and how to start developing USB devices A step by step method is used to guide you in developing USB devices The book is meant not only for beginners but also for those who have some USB experience They can What is USB Anyway use this book to develop a more complete view of the steps required to design a USB device The book shows you the steps required to start developing USB devices it discusses USB protocol a USB microcontroller and its firmware operating model USB device drivers based on the Windows Driver Model WDM Windows Applications and the development tools needed to develop USB devices The book also includes a d
126. nfigured for control transfer When a setup token arrives the device will activate its setup routines Other endpoints can also be configured for control transfer if required The setup routines that handle control transfer need special attention because the control transfer is typically completed over more than one USB frame Pre defined flags are needed to keep track of which stage the control transfer is in In a control transfer the first packet received will be a setup packet This setup packet has 8 bytes of 54 Step 4 Develop the Device Firmware data as specified by the USB Specification Chapter 9 of the USB Specification The device needs to decode the 8 bytes of data and determine which action is required and whether there will be a data stage Once the decoding and the setting up of the user flags have been completed it will go back to its idle stage It will wait there for the next stage of the control transfer The next stage of the control transfer will be either a status or data stage optional as indicated in the setup packet that was just received When a control transfer is completed after status stage all the user flags that were set need to be cleared and made ready for the next interrupt event This setup routine is discussed in greater detail in the USB Enumeration Code section 5 3 2 4 SOF Routines for control of isochronous transfer The host issues an SOF token at the nominal rate of 1 0 ms An interrupt can b
127. ntrol write When all the data has been collected Bytes received wLength the actual Routine is called The size of data is limited to this buffer length The code must then call SetUpcontrolWriteStatusStage to allow the status stage to continue OutReceived cjne A DATA_PHASE ReturnProcessOutToken Are we Processing a control Write i e Set Descriptor Added to handle control writes with data stages When a control Write with a data stage is detected 111 Firmware Code Example For Intel 8x930Ax USB Microcontroller the data is placed in the buffer CntlWriteDataBuffer push RO mov A HCntl WriteDataBuffer Get location of buffer add A CntlWriteDataPntr Add the offset mov RO A RO now contains the location to start storing the data Update the data stored in memory mov A RXCNT Get number of bytes to move add A CntlWriteDataPntr Add number received mov CntlWriteDataPntr A update memory variable mov A RXCNT JZ RdDone If no data in the buffer then exit ReadData mov R0 RXDAT Get the data and store it inc RO djnz ACC ReadData pop RO RdDone setb RXFFRC Update receive FIFO state Now check to see if this was the last read by checking if Bytes received wLength mov A CntlWriteDataPntr cjne A wLengtht 1 NeedMoreData If this is not equal to the expected then ljmp around ProcesscontrolWriteData push DPX Processing the jump table will corrupt DPX
128. ny SOF bit SOF interrupt enable bit frame timer lock bit and SOF pin disable bit SOFL Start of Frame Low Register To store the lower eight bits of the 1 1 bit time stamp from the SOF packets from the host TXCNTH Transmit Count High Register To store the MSB byte count for the data packets to be transmited in the transmit FIFO specified by EPINDEX TXCNTL Transmit Count Low Register To store the LSB byte count for the data packets to be transmited in the transmit FIFO specified by EPINDEX TXCON Transmit FIFO Control Register To control the transmit FIFO specified by the EPINDEX It enables or disables the flushing of the FIFO isochronous transfer and automatic transmit management TXDAT Transmit FIFO Data Register Transmit FIFO data as specified by EPINDEX is written to this register It serves as the interface between the microcontroller and the USB FIFOs TXFLG Transmit FIFO Flag Register To store the flags indicating the status of the data packets in the transmit FIFO as specified by the EPINDEX It has the transmit index empty full underrun and overrun flags TXSTAT Endpoint Transmit Status Register To store the status indicators of the transmit FIFO specified by EPINDEX It contains transmit endpoint sequence overwritten end overwrite transmit void transmit error and transmit acknowledge bits 47 Interface with the 8x930Ax It is very useful to organize these SFRs into logical groups for better und
129. o create a new instance of the device DriverObject pointer to the driver object for this instance of Test PhysicalDeviceObject pointer to a device object created by the bus Return Value STATUS_SUCCESS if successful STATUS UNSUCCESSFUL otherwise NTSTATUS ntStatus STATUS_SUCCESS PDEVICE_OBJECT deviceObject NULL PDEVICE_EXTENSION deviceExtension create our functional device object FDO ntStatus Test_CreateDeviceObject DriverObject amp deviceObject 0 if NT_SUCCESS ntStatus deviceExtension deviceObject gt DeviceExtension deviceObject gt Flags amp DO DEVICE INITIALIZING Add more flags here if your driver supports other specific behavior For example if your IRP MJ READ and IRP MJ WRITE handlers support DIRECT JO you would set that flag here deviceExtension gt PhysicalDeviceObject PhysicalDeviceObject Attach to the StackDeviceObject This is the device object that we use to send Irps and Urbs down the USB software stack deviceExtension gt StackDeviceObject IoAttachDeviceToDeviceStack deviceObject PhysicalDeviceObject ASSERT deviceExtension gt StackDeviceObject NULL 139 A WDM Driver Code Example return ntStatus NTSTATUS Test_CreateDeviceObject IN PDRIVER_OBJECT DriverObject IN PDEVICE OBJECT DeviceObject LONG Instance f Creates a Functional DeviceObject DriverObject pointer to the driver object for device DeviceObject pointe
130. oMarkIrpPending if ntStatus STATUS PENDING I IoMarkIrpPending Irp else if ntStatus goto Test Dispatch Done break IRP MI PNP POWER default Irp gt IoStatus Status STATUS INVALID PARAMETER ntStatus Irp gt IoStatus Status loCompleteRequest Irp IO NO INCREMENT Test Dispatch Done return ntStatus VOID Test Unload IN PDRIVER OBJECT DriverObject 134 Appendices FF Free all the allocated resources etc TODO This is a placeholder for driver writer to add code on unload DriverObject pointer to a driver object Return Value None NTSTATUS Test_StartDevice IN PDEVICE OBJECT DeviceObject Initializes a given instance of the Test Device on the USB DeviceObject pointer to the device object for this instance of a Test Device Return Value NT status code PDEVICE_EXTENSION deviceExtension NTSTATUS ntStatus PUSB DEV1CE DESCRIPTOR deviceDescriptor NULL PURB urb ULONG siz deviceExtension DeviceObject gt DeviceExtension deviceExtension gt NeedCleanup TRUE Get some memory from then non paged pool fixed locked system memory for use by the USB Request Block urb for the specific USB Request we will be performing below a USB device request urb ExAllocatEPOol NonPagedPool sizeof struct_ URB_Control DESCRIPTOR_REQUEST if urb siz sizeof USB_DEVICE_DESCRTPTOR 135 A WDM Driver Code Example Get some non paged memory for the devic
131. ocus on the USB device hardware and firmware and the other concentrates on the device drivers and application software on the USB host Companies wishing to design more complicated USB devices need to gather more resources into the project for example one for hardware one for firmware one for device driver and one for application software To design very complicated devices staff of up to 15 persons for each USB project might be needed This chapter describes the process of setting up a development environment using the 8x930Ax microcontroller solution for the device side It should be noted that setting up a development environment for other solutions would be similar 3 1 Development Environment Device Side There are two main development environments in creating a USB device one focusing on the USB device itself and the other on the USB host A typical development environment to build and test the device firmware and hardware is shown in Figure 3 2 Development Environment Device Side Start Step 1 Understanding the USB Specification Siep 2 Sel up a Development Environment Sien 3 Build Device Hardware Step 4 Develop Device Firmware Step 5 Develop Host Driver Step 6 Develop Application Sofware Step 8 Testing Erd Figure 3 1 Tasks to design a USB device PC OAI USB host and console for bus analyzer for assembler compiler debugger serial p
132. ointer to a buffer in which to place descriptor data outputs we put the device descriptor data if any is returned by the device in the system buffer and then we set the length in the Information 154 Appendices IT field in the Irp which will then cause the system to copy the buffer back A to the user s buffer length Test_GetDeviceDescriptor DeviceObject ioBuffer Irp gt IoStatus Information length Irp gt IoStatus Status STATUS SUCCESS break caselRP Test GET CONFIGURATION DESCRIPTOR inputs pointer to a buffer in which to place descriptor data outputs we put the configuration descriptor data if any is returned by the device in the system buffer and then we set the length in the Information field in the Irp which will then cause the system to copy the buffer back to the user s buffer length Test_GetConfigDescriptor DeviceObject ioBuffer outputBufferLength Irp gt IoStatus Information length Irp gt IoStatus Status STATUS SUCCESS break default Irp gt JoStatus Status STATUS INVALID PARAMETER switch on ioControlCode ntStatus Irp gt IoStatus Status loCompleteRequest Irp IO_NO_ INCREMENT d return ntStatus 155 A WDM Driver Code Example ULONG Test_GetDeviceDescriptor IN PDEVICE OBJECT DeviceObject PVOID pvOutputBuffer Gets a device descriptor from the given device object DeviceObject pointer to the test device object Re
133. on audio communications hub human interface image PC legacy physical interface power printer and storage Some specifications are in Rev 0 7 meaning the first draft incorporating initial round of comments from the members of the device working group Some specifications are in Rev 0 9 meaning all revisions are accepted by the working group and the specification is placed on the web sites for public comment or Rev 1 0 meaning it is ready for implementation by device vendors and will be posted on web sites The device working groups get together every 4 6 weeks for a face to face meeting The members of the groups come from various software and hardware companies For more information on the device working groups please contact the USB IF or the USB web site at http www usb org 6 2 Overview of WDM Microsoft publicly announced the Win32 Driver Model WDM at WinHEC 96 It is intended to provide a common driver architecture for Windows NT Windows 95 and future Windows operating systems It is 60 Step 5 Develop the USB Driver based on existing Windows NT driver models with additional Plug and Play and power management support Thus using the WDM a driver developed for Windows NT can be used in the other Windows environments as well The WDM supports new bus architectures like USB and the IEEE 1394 Firewire protocol Figure 6 2 shows a simplified view of the WDM software stack It is a more detailed view of the host
134. oneWithCommand GetlnStallStatus mov A EPCONO jnb ACC 7 NotStalled 118 mov A 01 DoneWithCommand NotStalled anl EPINDEX 80h mov TXDATO A mov TXDATO 00h mov TXCNTO 02 ReturnBadSTDGetEPCommand push EPINDEX mov EPINDEX 01 mov TXDAT 13h mov TXCNT 01h pop EPINDEX orl EPCONO H0COh RetumSTDGetEPCommand Ret for single packer Control read status SetUpSinglePacketControlReadStatusStage mov wLength 00 mov wLength 1 00 mov SetupRxFlag STATUS PHASE mov SetupTxFlag fDATA PHASE setb TXOE Ret Standard Set Endpoint Command StandardSetEndpointCommand push EPINDEX mov A wIndex 1 anl A HOFh orl EPINDEX A 119 Stall EPO Appendices Point the index back to EPO Advance flag to next state Enable data transmit Get the endpoint of the stall to clear Find out if this is an EPO CLear Stall Command Setup the EPINDEX to point at correct index Firmware Code Example For Intel 8x930Ax USB Microcontroller mov A wValue 1 cjne A ENDPOINT_ STALL ReturnBadSTDSetEPCommand mov A bRequest cjne A HCLEAR FEATURE CheckSetEndpointFeature ClearEndpointFeature CLEAR ENDPOINT STALL ClearEndpointStall mov A wIndex 1 Get the endpoint of the stall to clear anl A HOFh Find out if this is an EPO CLear Stall Command INZ ClearNonEPOStall anl EPCON 03Fh For EPO Clear both TX amp RX stall bits ljmp ReturnSTDSetEPCommand ClearNonEPOStall mov A
135. onnect to upstream hubs or devices as depicted in Figure 2 5 USB series A FUNCTIONS Figure 2 5 Usage of series A and series B connectors The standard USB cable consists of one pair of 20 28 AWG wires for power distribution with another 28 AWG pair twisted with shield and overall jacket The cross section of the cable is shown in Figure 2 6 This cable is used for devices operating at 12 Mbps Full Speed 13 USB Mechanical and Electrical Power pair Differential Signal pair Figure 2 6 Cross section of a full speed USB cable For low speed devices operating at 1 5 Mbps an alternative cable of identical gauge but without the twisted conductors and shield can be used As shown in Figure 2 6 there are four USB wires two for power supply Vbus and GND and two for signaling D and D For a full speed device a 1 5 kQ 5 pull up resistor is required on the D line as shown in Figure 2 7 USB device Figure 2 7 Connection of external resistors in a full speed device Series resistors of typically 29 44 Q are also required to connect to the USB wires as shown in Figure 2 7 for impedance matching For low speed devices the 1 5 kQ 5 resistor must be tied from the D wire to a voltage source between 3 0 and 3 6 v Step 1 Understand the USB Specification 2 7 1__Power Supply from USB Wires USB provides limited power supply to its devices The voltage supply is between 4 75v 5 25v Vous from th
136. ontext switching This provides the illusion that all threads are executing simultaneously Negative acknowledgment Handshake packet indicating a negative acknowledgment Non Return to Zero Invert A method of encoding serial data in which ones and zeroes are represented by opposite and alternating high and low voltages where there is no return to zero reference voltage between encoded bits Eliminates the need for clock pulses The section of the Windows NT operating system that runs in kernel mode to provide process structure inter process communication memory management object management thread schedul ing interrupt processing I O capabilities networking and object security Host software or data structure representing a Universal Serial Bus entity The components of the NT executive that creates deletes and names operating system resources which are stored as objects 103 Glossary OSI Packet Packet ID PCI Physical device Pipe PLL PnP Polling POTS Process Open System Interconnect reference model A software model defined by the International Standards Organization ISO that standardizes levels of service and types of interaction for net worked computers and communication systems A group of data for transmission Packets typically contain three elements control information e g source destination and length the data to be transferred and error detection and correction
137. opp Frame CMainFrame in MainFimh and MarFim cpp Document CTesDoe in lastDor hand testDoc cpp View CTealView in testView h and tesiview cop Features Initial toolbar in main frame Intial status bar in main frame Pinlig ond Pini Preview support in view 30 Contiok Uses shared DLL implementation MELO DL Localizeble text in Figure 7 4 A skeleton project created by AppWizard In this example four C C files and the corresponding header files are generated as shown in Figure 7 4 test cpp is the application class for the program derived from the CWinApp MainFrm cpp is the main frame class of the program testDoc cpp is the program s document class derived CDocument test View cpp is the program s view class derived from the CView 82 Step 6 Developing Host Application Software Microsoft Developer Studio test ftest re File Edit View Insert Build Jools Window Help test resources HEJ Accelerates a C3 Menu Se wE Shing Table g Toolbar SL Cl Version Figure 7 5 Menu item properties of the About test These C C files provide basic software routines to build our project To examine these C C files look at an example Choose to investigate the About test menu item View it using the Menu folder from the Resource View tool by clicking on the Resource View tab in the project workspace window as shown in Figure 7 5 By double clicking the About test item in the menu o
138. or 12H overrides the previous expected length of the packets 0080H by the host as indicated in packet 181 The status stage of the device is shown in the USB frame starting with packet 198 The host in this case sends out an OUT token The token for the status stage is always opposite to that of the data stage In our example we have IN tokens in the data stage and thus an OUT token and a null packet will be sent in the status stage Note that there are some control transfers that have no data stage for example the SET CONFIGURATION setup packets For this case the host will issue an IN token for the status stage 2 9 2 Isochronous Transfer Isochronous transfers have token and data phases It is completed within a USB frame If the host sends an IN token the device will transmit data to the host If the device receives an OUT token from the host it will anticipate data from the host immediately after the OUT token There is no handshake phase for isochronous transfers 2 9 3 Bulk Transfer The bulk transfer is similar to the isochronous transfer except that it has a handshake phase after the data phase This is to ensure that the data is sent or received accurately An ACK handshake packet will be sent if the data is received without error by the host or by the device The device can also return a NAK or STALL handshake A NAK handshake indicates that the device is temporarily unable to perform the request by the host A STALL ha
139. ort 8x930Ax evaluation kit bus analyzer pass thru application hardware Figure 3 2 Development environment device side We first purchase an 8x930Ax USB Evaluation Kit It consists of a 8x930Ax microcontroller on an evaluation board an evaluation copy of an assembler compiler and debugger either from PLC Tasking or Keil and Apbuilder software which helps designers understand the 32 Step 2 Set Up a Development Environment architecture of the 8x930Ax microcontroller The contact numbers to purchase this Evaluation Kit are listed in the next section In the development environment above firmware engineers can write their codes on a PC called PC A in Figure 3 2 and then test the codes by downloading and then executing them on the evaluation board The codes are downloaded through the serial port of the PC Firmware called RISM residing in the Evaluation Kit performs the communication between the PC and the evaluation board through the serial port The evaluation board also provides an interface to the USB device we will build Hardware designers can test out prototypes by interfacing to this evaluation board Testing the device firmware can be done in a modular fashion For example you can try out the operation of the firmware for the device without USB functionality first In the other firmware module we can test the USB functions independently When both firmware modules work well separately they can be m
140. ort expansion USB provides a low cost PC port extension and allows up to 127 device attachments for a single PC host The low cost objective is one of the reasons that the USB rate is at 12 Mbps as higher rates usually mean more expensive shielding chip sets components etc There are in fact two categories of USB devices that can be connected to the same USB host one consists of full speed devices at 12 Mbps and the other type consists of low speed devices at 1 5 Mbps Examples of low speed devices are mice and keyboards which do not require the full 12 Mbps speed and are very cost sensitive With the 12 Mbps and 1 5 Mbps low speed bus in mind USB is not targeted for very high speed applications like disk drives or full motion video applications It is targeted for low and medium speed applications like keyboard mice modems CTI low speed scanners low speed printers and low speed cameras As a rule of thumb a device that requires more than 4 Mbps of bandwidth constantly is not suitable as a USB device 2 3 USB Bus Topology The USB Specification defines the interconnections and communications between two main elements of a USB system USB host PC and USB devices Its physical interconnection topology is a tiered star as shown in Figure 2 1 Step 1 Understand the USB Specification HOST ROOT HUB USB i HONE FUNCTIONS HUB USB FUNCTIONS USB FUNCTIONS Figure 2 1 USB bus topology There is only ONE ho
141. ous Receiver and Transmitter UART 37 106 Universal Host Controller Interface UHC harec 30 61 Universal Serial Bus Device USBD E 9 106 Universal Serial Bus Interface 106 Universal Serial Bus Software 106 Upstream eeen 106 Upstream Devices cecee B PSB eege ees 106 USB Dk A USB Driver USBD 30 61 USB Request Block URB EE 6 9 USB Implementers Forum 2 User Mode 61 64 106 V estate Gute 14 15 22 Vendor Identification Information id encore R W WDM DDK rrrvrrrvrrnrrrnrrsvrnrrrnrrnsene amp 8 WDM Device Driver 68 WDM USB DIDK kd Win32 Driver Model WDM 6 Win32 SDK 34 Windows Driver Model 34 Windows NT errvvnrrrorrnvrrrnnrrerr 34 62 Windows NT DDK Q rnnvrornvnnnennrr 4 Windows NT Driver Model 62
142. pe is a standard request and the recipient of this packet is the device Section 9 3 of the USB Specification enables us to decode what is meant by the setup data The second byte is 06H which can be decoded as a GET DESCRIPTOR request and so on The last word 2 byte is 0080H which is the expected length of the packets that the device is required to send in the data stage data stage exists if this word is not OOOOH This is the setup stage for a control transfer The device after the correct reception of this setup data issues an ACK handshake packet packet 182 immediately Note that all of these transfers take place within I ms between SOF packet 179 and SOF packet 183 Since the host requests to get data from the device it will send an IN token after the setup packet as shown in the USB frame starting with 19 USB Protocol by Transfer Types packet 183 The device responds with the data the host requested This is the beginning of the data stage of the control transfer Note that the control transfer is done over a few USB frames as signified by the multiple SOF tokens between the packets The data stage carries on until the device finishes the required data The length of the device s descriptor is stated in the first byte of the data i e for our example it is 12H as in packet 185 To decode the device s descriptor please refer to section 9 6 1 of the USB Specification Note that this first byte of the device s descript
143. r The host has knowledge of all the bus access requirements of its devices and schedules all the bus activities 2 2 USB Objectives USB was developed to achieve three main goals e Fase of use It achieves this goal by providing a hot out of box Plug and Play environment Users do not have to open the PC case configure interrupts set dip switches and so forth just to install a new PC peripheral All you have to do is attach the USB device to a USB connector The USB PC will recognize the newly attached device instantly and exchange information with the device about its USB Bus Topology manufacturer its type its version number and so forth If a USB device is detached from the PC the PC will recognize this and notify the application software of the device The application may then notify users that the device has been removed e PC phone connection USB provides the ability to support real time data e g voice audio and compressed video and asynchronous messaging For example before USB it was extremely difficult to provide a voice path together with control data into or out of a PC using serial or parallel ports With USB the voice and control data are divided into different pipes that go into or out of a PC This is achieved using the endpoint notation more of this in later sections Moreover USB can bring multiple voice paths into and out of the PC which cannot be easily done by serial or parallel ports P
144. r They can be used as general purpose 8 bit 13 bit or 16 bit timers counters timers for captured events on an external pin timers for outputting a programmable clock signal on an external pin or as a baud rate generator for the on chip serial port UART etc 4 1 5 2 Hardware Watchdog Timer When initiated by firmware the watchdog timer starts running and unless the firmware intervenes it will reach a maximum count and reset the controller It is used to return the device to a known stage in the event of unrecoverable errors 4 1 5 3 Programmable Counter Array PCA The PCA has its own timer and five capture compare modules that can be used to perform several functions such as e capturing the timer value in response to a transition on an input pin e generating an interrupt request when the timer matches a stored value toggling an output pin when the timer matches a stored value e generating a Pulse Width Modulation PWM signal which can be used as a D A converter e serving as a software watchdog timer 4 1 5 4 Serial Port UART There is one configurable four mode two wire serial port in the 8x930Ax Mode 0 enables the serial port to behave as a half duplex synchronous serial port one pin TxD pin outputs the clock signal and the other pin RxD pin receives and transmits data The baud rate is at 2 Mbps for the 8x930Ax operating on a crystal clock of 12 MHz with PLL enabled In mode 1 2 or 3 the serial port is in its as
145. r to DeviceObject pointer to return created device object Instance instnace of the device create Return Value STATUS SUCCESS if successful STATUS UNSUCCESSFUL otherwise Mi NTSTATUS ntStatus WCHAR deviceLinkBuffer L DosDevices Test 0 UNICODE STRING deviceLinkUnicodeString WCHAR deviceNameBuffer L Device Test 0 UNICODE STRING deviceNameUnicodeString PDEVICE EXTENSION deviceExtension deviceLinkBuffer 19 USHORT 0 Instance deviceNameBuffer 15 USHORT 0 Instance RtIInitUnicodeString amp deviceNameUnicodeString deviceNameBuffer ntStatus IloCreateDevice DriverObject sizeof DEVICE EXTENSION amp deviceNameUnicodeString FILE DEVICE UNKNOWN 0 140 Appendices FALSE DeviceObject if NT_SUCCESS ntStatus RtlInitUnicodeString amp deviceLinkUnicodeString deviceLinkBuffer ntStatus IoCreateSymbolicLink amp deviceLinkUnicodeString amp deviceNameUnicodeString Initialize our device extension deviceExtension PDEVICE_EXTENSION DeviceObject gt DeviceExtension RtlCopyMemory deviceExtension gt DeviceLinkNameBuffer deviceLinkBuffer sizeof deviceLinkBuffer deviceExtension gt ConfigurationHandle NULL deviceExtension gt DeviceDescriptor NULL deviceExtension gt NeedCleanup FALSE Initialize our interface deviceExtension gt Interface NULL return ntStatus VOID Test_Cleanup PDEVICE_OBJECT DeviceObject
146. rHnd free pTestDesc return CWinApp ExitInstance void CUsbappApp OnGetdesDevice PVOID pvBuffer 0 pvBuffer malloc sizeof Usb_Device_Descriptor 64 Perform the Get Descriptor IOCTL 169 An Application Software Code Example DeviceloControl hDrvrHnd IRP Test GET DEVICE DESCRIPTOR pvBuffer sizeof Usb Device Descriptor pvBuffer sizeof Usb Device Descriptor amp dwStatus NULL free pvBuffer AfxMessageBox completed Get Descriptors Device void CUsbappApp OnGetOne PVOID pvBuffer 0 pvBuffer malloc sizeof Usb Device Descriptor 64 Perform the Get Descriptor IRP DeviceloControl hDrvrHnd IRP Test GET CONFIGURATION DESCRIPTOR pvBuffer sizeof Usb Device Descriptor pvBuffer sizeof Usb Device Descriptor amp dwStatus NULL free pvBuffer AfxMessageBox completed Get Command One void CUsbappApp OnGetTwo PVOID pvBuffer 0 pvBuffer malloc sizeof Usb_Device_Descriptor 64 Perform the Get Descriptor IRP 170 Appendices DeviceloControl hDrvrHnd IRP Test GET CONFIGURATION DESCRIPTOR pvBuffer sizeof Usb Device Descriptor pvBuffer sizeof Usb Device Descriptor amp dwStatus NULL free pvBuffer AfxMessageBox completed Get Command Two void CUsbappApp OnSetOne not implemented yet AfxMessageBox This function has not been implemented JEI PVOID pvBuffer 0 pvBuffer
147. rocess enables the Hot Plug and Play feature of USB The device goes through the following stages as shown in Figure 2 14 Configured Figure 2 14 USB enumeration state diagram 21 USB Functions When a USB device is attached it undergoes the following actions 1 The hub or root hub where the device is attached informs the host that an event has occurred There are two 15K pull down resistors connected to the D and D USB wires in the hub port or root hub in the host When the device is attached its pull up resistor see USB Mechanical and Electrical section will cause the signal level of either D or D to rise thereby signaling the attachment of a USB device The device is now considered to be in the attached stage see Figure 2 14 The host inquires the hub regarding the nature of the event The host issues a port enable and reset command to the hub where the device is attached 4 The hub will then issue a USB reset signal to that port for 10 ms and provide 100 mA of power supply to the device after the reset signal is completed The device now is considered to be in the powered stage as shown in Figure 2 14 From the device point of view the reset signal is the first signal it sees when it is attached to the hub or root hub After the reset signal the device is in its default stage where it corresponds to the host with its default address address 0 and endpoint 0 5 The host will then initiate a GET DE
148. rrvrevvvrrevnvnvnnvvvnnnnnene 65 FIGURE 6 5 WINDOWS NT I O sws 67 FIGURE 6 6 AN I O REQUEST EXAMDLE 72 FIGURE 7 1 STARTING A NEW PROJECT WORKSPACE esooseeneneeeseeeee 80 FIGURE 7 2 USING APP WIZARD EE 81 XIII FIGURE 7 3 STEP OF THE OF THE APPWIZARD eoorerorenvnvvrrrrnvnnvnnnnnenee FIGURE 7 4 SKELETON PROJECT CREATED BY APPWIZARD FIGURE 7 5 MENU ITEM PROPERTIES OF THE ABOUT TEST FIGURE 7 6 ID APP ABOUT IN THE BEGIN MESSAGE MAP ROUTINE 000000 FIGURE 7 7 ONAPPABOUT ROUTINE sanse FIGURE 8 1 LAB SETUP TO USE THE USB CODE EXAMPLES 0 ececceeeeeee FIGURE 8 2 A UNKNOWN DEVICE SCREEN ON THE HOST PC FIGURE 8 3 LOADING PROCESS OF WDM DRIVER FOR THE NEWLY ATTACHED DEVICE FIGURE 8 4 TEST APP EXE APPLICATION SOFTWARE USER INTERFACE 93 FIGURE 8 5 ACTIVATE THE MENU ITEM TO GENERATE AUSB TRANSACTION ee FIGURE 8 6 USB TRANSACTIONS AS CAPTURED BY A CATC BUS ANALYZER FIGURE 8 7 LOCATING THE PRODUCT INFORMATION IN THE REGISTRY 95 XIV Foreword Universal Serial Bus USB is one of the most important developments in PC peripheral interconnect technology since the introduction of serial and parallel ports in the early 1980 s It is fast becoming the port of choice for many new digital video conferencing cameras scanners monitors PC telephony equipment and Human Interface Devices such as keyboards games and pointing devices The benefits of USB such as ease of use true plug
149. sCommands not implemented yet ret 115 Firmware Code Example For Intel 8x930Ax USB Microcontroller STANDARD COMMANDS further decode the standards commands StandardGetDeviceCommand mov A bRequest cjne A GET_ DESCRIPTOR CheckGetConfiguration mov A b Descr iptorType cjne A DEVICE_DESCR CheckConfigDescriptor GET DESCRIPTOR DEVICE mov ControlBuffLocation LOW HIGH16 BEGIN DEVICE DESCRIPTOR mov ControlBuffLocation 1 HIGH LOW16 BEGIN_DEVICE_DESCRIPTOR mov ControlBuffLocation 2 LO W LOW 16 BEGIN DEVICE DESCRIPTOR mov A 12h mov B 00h ljmp LoadBuffer CheckConfigDescriptor cjne A CONFIG_DESCR CheckStringDescriptor GET DESCRIPTOR CONFIGURATION mov ControlBuffLocation LOW HIGH16 BEGIN CONFIG DESCRIPTOR mov ControlBuffLocation 1 HIGH LOW16 BEGIN CONFIG DESCRIPTOR mov ControlBuffLocation 2 LOW LOW 1 6 BEGIN CONFIG DESCRIPTOR mov A LOW END CONFIG DESCRIPTOR BEGIN CONFIG DESC RIPTOR mov B HIGH END CONFIG DESCRIPTOR BEGIN CONFIG DESCRIPTOR ljmp LoadBuffer CheckStringDescriptor cjne A HSTRING DESCR ReturnBADSTDGetDeviceCommand pm GET DESCRIPTOR CONFIGURATION mov ControlBuffLocation LOW HIGH 16 STRING 1 mov ControlBuffLocation 1 HIGH LOW 1 6 STRING 1 116 Appendices mov ControlBuffLocation 2 LOW LOW16 STRING 1 mov A LOW STRING 2 STRING 1 mov B HIGH STRING 2 STRING 1 limp LoadBuffer LoadBuffer Compare to see whic
150. scriptor gt bNumInterfaces numberOfinterfaces 1 numberOfPipes 0 Initialize to zero We use alternate interface setting 0 for all interfaces This is a simplification and is due to change in future releases of this driver If your driver supports alternate settings you will have to do more work to switch between alternate settings alternateSetting 0 Call a USBD helper function that returns a ptr to a USB Interface A Descriptor given a USB Configuration Descriptor an Inteface Number and an Alternate Setting for that Interface interfaceDescriptor USBD ParseConfigurationDescriptor ConfigurationDescriptor MylnterfaceNumber interface number this is binterfaceNumber from interface descr alternateSetting ASSERT interfaceDescriptor NULL Add to the tally of pipes in this configuration numberOfPipes interfaceDescriptor gt bNumEndpoints Now that we have looked at the interface we configure the device so that the remainder of the USBD objects will come into existence ie pipes etc as a result of the configuration thus completing the configuration Process for the USB device 148 Appendices IT Allocate a URB big enough for this Select Configuration request siz GET SELECT CONFIGURATION REQUEST SIZE numberOflnterfaces numberOPipes urb ExAllocatepool NonPagedPool SiZ if urb interfaceObject PUSBD_INTERFACE INFORMATION amp urb gt
151. sed by the host to determine which driver to load The synthesis of these values is used to match the Hardware ID in an INF file Windows NT Information file When a match is found the INF file with the matching Hardware ID is used to load the driver The Hardware ID in the INF file is described in the device description entry An example of an INF file to load the driver uhcd sys for the device one of the devices that the INF file supports with idVendor 8086 hex idProduct 7020 hex is shown in the following code Please refer to Manufacturer and Intel Section of the entries 72 Step 5 Develop the USB Driver an INF file example USB INF This file contains descriptions of all the HDC USB controller Created 10 2 95 Creation Date Version signature CHICAGO Class USB Class GUID 36F C9E60 C465 JICF 8056 444553540000 Provider Msft LayoutFile LA YOUT INF DestinationDirs DefaultDestDir 1 I LDID_SYS Class Sections Classinstall Addreg USBClassReg USBClassReg HKR USBClassName HKR Icon 20 y Table of content Manufacturer Generic Mfg Generic Section GenericHub Mfg GenericHub Section Compaq Mfg Compaq Section intel Mfg Intel Section Philips Mfg Philips Section NEC Mfg NEC Section PLX Mfg PLX Section VIA Mfg VIA Section 5 Generic Generic Section PCNCC_OC0310 DeviceDesc OpenHCD Dev PCNCC_0C
152. sers and communicates to the WDM drivers of the USB devices In this chapter we describe a way to develop host application software using Microsoft Visual C 4 0 and the Microsoft Developer Studio Sample application software is also included on the enclosed diskette and in Appendix C for your reference 7 1 Microsoft Developer Studio The main part of the Visual C package is the Developer Studio It is an Integrated Development Environment for editing compiling and debugging programs in a single environment The Developer Studio includes several tools to create the application software Among other things it has e aC C compiler e an integrated editor e a Component Gallery to store organize and reuse our software routines and e an integrated debugger for steping through and checking the source code The Microsoft Developer Studio also includes five wizards that can be used to simplify the development of Windows programs The five wizards are AppWizard Used to create the basic outline of a Windows program It supports three program types 1 Single Document and 2 Multiple Document applications based on the Document View architecture and 3 dialog box based programs in which a dialog box serves as the main window for the application The basic idea of the Document View architecture is to separate the data handling classes from the classes that handle the user interface The view class is responsible to provide a v
153. sessssseeeene 17 FIGURE 2 13 AN EXAMPLE OF CONTROL TRANSFER soseeneeeseeeeeeeeee 19 FIGURE 2 14 USB ENUMERATION STATE DIAOGRANM evvvrrrnvnvnvvvvnenvnvees 21 FIGURE 2 15 INTER LAYER COMMUNICATION MODEL 29 FIGURE 3 1 TASKS TO DESIGN A USB DENMICE 32 FIGURE 3 2 DEVELOPMENT ENVIRONMENT DEVICE SIE 32 FIGURE 3 3 DEVELOPMENT ENVIRONMENT HOST USB DRIVER 34 FIGURE 4 1 8x930Ax PRODUCT OPTIONS evemerernrnnvnvrrevnnnnnnvvnnnnnnener 37 FIGURE 4 2 8x930Ax ADDRESSING SPACE WHEN CONFIGURED TO 256 KBYTES OF ADDRESSING ssssseesecsecceseeeeeeeeeee 39 FIGURE 4 3 PAGE MODE FOR EXTERNAL MEMORY ACCESS 40 FIGURE 4 4 THE USB MODULE OF THE 8x930AX eevvrornrevvvvvenerrrsrnrernr 44 FIGURE 4 5 INTERFACES OF THE 8X930AX rerororrrrrnrnnnnvrnnenenrrersvnnne 48 FIGURE 5 1 USB DEVICE PROGRAM FLOW nsssessssseseseseseseersesrsreeee 51 FIGURE 5 2 OPERATION OF TRANSMIT ROUTINES ooovnnnnnnvvevnnnnnvvvnnenen 53 FIGURE 5 3 OPERATION OF RECEIVE ROUTINES sseeeeccceeeeceeeeeee 54 FIGURE 5 4 OPERATION OF SOF ROUTINE eossosssseenesseessesesrerresss 55 FIGURE 5 5 FLOW DIAGRAM OF THE ENCLOSED USB_ENUM ASM 56 FIGURE 5 6 FLOW DIAGRAM OF THE USB ENUM ASM rrnrvrvrrrnnnnn 57 FIGURE 6 1 RELATIONSHIP OF THE USB HOST AND THE USB DEVICE 60 FIGURE 6 2 WDM SOFTWARE STACK evvvvrrnrnnnnnvnnnnnvrvernnnnnnnnnnnnnneeee 6l FIGURE 6 3 A CLIENT SERVER OPERATING SYSTEM 63 FIGURE 6 4 WINDOWS NT BLOCK DIAGRAM e r
154. side of Figure 6 1 The class device drivers are just below the user mode API layer While the device class drivers are specified by the device working groups individual manufacturers can choose to develop their own mini driver to differentiate their products or to be in the market before the class drivers are available All these class drivers and mini drivers interact to a USB driver In the layer below the USB driver there are UHCI Universal Host Controller Interface and OHCI Open Host Controller Interface drivers which interact with the host controller hardware Both the OHCI and UHCI host controllers are supported by the WDM architecture The host controllers will then communicate to the USB devices via the Serial Interface Engine SIE and the USB wires Client Application software user mode USB System kernel mod WDM software i S stack USB Driver USBD SYS Host controller driver UHCLSYS or OHCI SYS USB Bus SIE Figure 6 2 WDM software stack 61 Windows NT System Overview 6 3 Windows NT System Overview Since the WDM is based on the Windows NT driver model it is essential that we understand the Windows NT operating system and its system architecture s Windows NT is considered to be Microsoft s highly portable next generation 32 bit Windows multitasking operating system It divides the work that needs to be done among its processes Each process has its resources like memory system resourc
155. st in a USB system The USB Host is a PC with a USB host controller and it may be implemented in a combination of hardware firmware or software In this book we focus on the USB devices The details of the USB host can be found in Chapter 10 of the USB Specificationr The host is the master of the USB system It controls and schedules all the activities in its system A root hub is integrated within the host to provide one or more attachment points There are two types of USB devices USB Hub and USB functions The USB hubs provide extra attachment points for the system We can think of them as the socket extensions used to connect additional electrical appliances The USB functions provide capabilities to the system e g keyboard joystick etc The USB functions are the focus of this book and the terms function and device are used interchangeably in this book 2 4 USB Data Flow Model USB provides a protocol for communications between the devices and the host Although the bus topology of a USB system is a tiered star Figure 2 1 the connection of the USB devices to the USB host can be thought of as one to one as shown in Figure 2 2 This is referred to as USB Pipe Concept Device Address and Endpoint the logical connections of the USB system The data flow model is based Host Seas Sc WORM re Logical Dee Gs Device E ical Device fm FG Logical Device Logical N Device on these logical connections Figure 2 2
156. sume reset flags These flags will be set accordingly when there is a USB suspend resume and reset RXCNTH Receive FIFO Byte Count High Register To store the MSB byte count for the data packets received in the receive FIFO specified by EPINDEX RXCNTL Receive FIFO Byte Count Low Register To store the LSB byte count for the data packets received in the receive FIFO specified by EPINDEX Receive FIFO Register To control the receive FIFO specified by the EPINDEX tt enables or disables the flushing of the FIFO isochronous transfer and automatic receive management RXDAT Receive FIFO Data Register Receive FIFO data as specified by EPINDEX is read from this register It serves as the interface between the microcontroller and the USB FIFOs RXFLG Receive FIFO Flag Register To store the flags indicating the status of the data packets in the receive FIFO as specified by the EPINDEX It has the receive index flag empty flag full flag underrun flag and overrun flag RXSTAT Endpoint Receive Status Register To store the status indicators of the re ceive FIFO specified by EPINDEX It contains receive endpoint sequence receive setup token overwritten end overwrite receive data sequence overwrite receive void receive error and receive acknowledge bits SOFH Start of Frame High Register To store the upper 3 bits of the 1 1 bit time stamp from the SOF packets from the host It also contains SOF token receive acknowledgment bit a
157. t then proceeds to the status stage of this control transfer by sending an OUT token and a null packet to our device as shown in packet 38 and 39 respectively Our device sends a handshake packet 38 Syne 00000001 OUT 0x87 ADDR Ox00 ENDP 0x0 CRCS 0x08 39 Syne 00000001 DATA1 0xD2 DATAQ CRC16 0x0000 40 Sync 0000001 ACKOx4B S O 41 Synet 0000001 SOF OxA5 Frame 0x493 CRCS 0x05 The host PC then proceeds to send the SET ADDRESS command to the device as shown in packet 122 The second byte of 05H can be decoded accordingly packet 40 23 USB Functions Our device acknowledges the SET ADDRESS command packet 123 as the SET ADDRESS command The 3rd and 4th bytes of packet 122 are 02H which is the new address assigned by the host to the 119 Sync 00000001 SOF 0xA5 Frame 0x4F7 GRC5 Dx12 130 Syne 00000007 SOFIOxAS Frame MOAF CRES SS Syne 00000001 SETUP 0xB4 ADDR 9x00 ENDP 0x0 CRC5 0x08 122 L123 I 124 Sync 0000001 SOF 0xA5 Frame 0x4F9 CRCS 0x1D 125 1 Sync 00000001 IN Dx96 ADDR 0x00 ENDP 0x0 CRC5 0x08 126 127 Syne 00000001 DATA 1 0xD2 DATAS CRC 16 0x0000 Syne 0000001 ACK Qx48 and the host then proceeds to the status stage of this control transfer as depicted by packets 125 to 127 Note that before and during this status stage of SET ADDRESS our device still communicates with the host using its default addr
158. the Author It was my top priority to ensure that all the information provided is as correct as possible and as simple as possible to understanding However if you find any errors or omissions that are critical to this book please send your feedback to the author Thank you and get into the BUS E Mail address wtan annabooks com Step 1 Understand the USB Specification 2 Step 1 Understand the USB Specification The first step to design a USB device is to understand the USB Specification The USB Specification 1 0 has 267 pages however the good news is that we do not have to go through all the pages before starting to design a USB device This chapter gives sufficient knowledge of the USB Specification made simple to comprehend for us to start designing a USB device For more details refer to the USB Specification Lin 2 1 Summary of USB Protocol USB is a 12 Mbps serial channel that is shared by a wide variety of PC peripherals up to 127 peripherals total can be mounted in a single PC It has four wires two wires for supplying the power and two wires for data transfer It is a token based bus protocol where the USB host is the master of the bus The host broadcasts tokens on the bus and a device that detects a match in its address as described in the token responds to the host The 12 Mbps bandwidth of the bus is framed into I ms slots and shared by all the devices in the bus in a time division multiplexed TDM manne
159. the operation as specified by the IRP and then either passes it back to the I O manager after completion or passes it on to another driver via the I O manager for further processing 66 Step 5 Develop the USB Driver environment subsystem DLL BE services ENER GEN device drivers oD CS hardware video monitor disk drive network device etc user mode kernel mode file system and network drivers NT executives We Figure 6 5 Windows NT I O system The I O manager provides functions common to all drivers like a function that allows one driver to call another The driver can call those functions to carry out their I O processing The I O manager also manages the buffer for I O requests provides time out support for drivers and provides flexible I O facilities to allow environment subsystems to implement their respective I O APIs 6 4 1 NT Object Model In Windows NT any I O device is treated as if it was a file and is referred to as a virtual file Windows NT programs perform I O on virtual files manipulating them using file handles Within the NT executive the file handles are referred to as file objects Application program can call the NT file object services to read from a file write to a file or perform other operations The I O manager dynamically directs these virtual file requests to real files or physical devices Applications open a file by using a standard library function and
160. tion board evaluation copy of assembler compiler and debugger from a third part vendor and Apbuilder software A handle to a file object which is used by application software to communicate to the object The time frame from the start of SOF token to the start of SOF token of the subsequent token This period has a nominal value of I ms as defined by the USB Specification 101 Glossary Full duplex HAL Handshake packet Host Hub Interrupt transfer I O Manager IRP ISDN Isochronous transfer Data transmission occurring in both directions simultaneously Hardware Abstraction Layer A DLL that protects the NT executive from variations in different vendors hardware platforms This makes the operating system more portable A packet that acknowledges or rejects a specified condition See ACK and NACK The host computer system where the USB host controller is installed It includes the host hardware platform and the operating system in use A USB device that provides additional connections to the USB bus One of four USB transfer types Its transfer characteristics are small data non periodic low frequency bounded latency device initiated but polled by host communications typically used to notify the host of a device service need One of the Windows NT executive components It defines an orderly framework within which I O requests are accepted and delivered to file systems and device dri
161. to create a file handle with the matching TRYING_00 symbolic link Il in the application software codes Int CMainFrame OnCreate hDrvrHnd CreateFile TRYING_00 GENERICJVRITE GENERIC READ FILE SHARE WRITE FILE SHARE READ NULL OP EN _EXISTING 0 NULL In this manner the application software can link and communicate with the device driver of the USB device to perform various application functions 7 4 Communicating to the WDM Driver After the above loading and linking of the driver object to the application software the application is ready to communicate to the driver A system routine DeviceloControl is used by the application software to send command code directly to the device driver making the corresponding device perform specified functions The Devicelo Control routine has the following parameters 85 Communicating to the WDM Driver BOOL DeviceloControl HANDLE hDevice DWORD the handle to the device driver dwhControlCode LPVOID control code of operation to perform IpInBuffer DWORD pointer to the input data buffer ninBufferSize LPVOID size of the input buffer IpOutBuffer DWORD pointer to the output data buffer nOutBufferSize LPDWORD size of the output buffer IpBytes Returned pointer to variable to receive output byte count LPOVERLAPPED IpOverlapped pointer to overlapped structure for asynch op For example say a menu item has been defined
162. to send a packet of information to a USB device through the WDM driver Define the menu item Get Command One for this purpose In the Menu Item Properties define the ID for this Get Command One function naming it ID GET ONE This ID GET ONE is then used in the application routine ON COMMAND ID GET ONE OnGetOne of the BEGIN MESSAGE MAP routine as shown below In the OnGetOne routine include the following code to send an IRP using the DeviceloControl routine to the USB device driver application software code example headers files BEGIN_MESSA GE_MAP CVsbappApp CWinApp ON COMMAND ID APP ABOUT OnAppAbout ON COMMAND ID SET ONE OnSetOne ON COMMAND ID SET TWO OnSetTwo ON COMMAND ID GET ONE OnGetOne ON COMMAND ID GET TWO OnGetTwo Standardfile based document commands ON COMMAND ID FILE NEW CWinApp OnFileNew ON COMMAND ID FILE OPEN CWinApp OnFileOpen Standard print setup command ON COMMAND ID FILE PRINT SETUP CWinApp OnFilePrintSetup END MESSAGE MAP Il others routines 86 Step 6 Developing Host Application Software Ai OnGetOne routine void CUshappApp OnGetOne PVOID pvBuffer 0 pvBuffer malloc sizeof Usb Device Descriptor 64 Perform the Get Descriptor IRP DeviceloControl hDrvrHnd IRP Test GET CONFIGURA TION DESCRIPTOR pvBuffer size of Usb Device Descriptor pvBuffer sizeof Usb Device Descriptor amp dwsSta
163. turn Value Number of valid bytes in data buffer PDEVICE EXTENSION deviceExtension NULL NTSTATUS ntStatus STATUS SUCCESS PURB urb NULL ULONG length 0 deviceExtension DeviceObject gt DeviceExtension urb ExAllocatepool NonPagedPool sizeof struct URB Control DESCRIPTOR REQUEST if urb if pvOutputBuffer UsbBuildGetDescriptorRequest urb USHORT sizeof struct _URB Control DESCRIPTOR REQUEST USB DEVICE DESCRIPTOR TYPE descriptor type 0 lindex 0 Nanguage ID pvOutputBuffer transfer buffer NULL IMDL sizeof USB_DEVICE DESCRIPTOR buffer length NULL link ntStatus Test_CallUSBD DeviceObject urb else ntStatus STATUS NO MEMORY 156 Appendices II Get the length from the Urb length urb gt UrbControlDescriptorRequest TransferBufferLength ExFreepool urb else ntStatus STATUS NO MEMORY return length Je not tested it yet NTSTATUS SetOne IN PDEVICE OBJECT pDeviceObject PUSBTESTCTRLDESC pTestCtrlDesc perform a set setup packet Return Value ntstatus NTSTATUS ntStatus PURB pUrb pTemp ExAllocatepool NonPagedPool sizeof USBDISPDESC pUrb ExAllocatepool NonPagedPool sizeof struct _URB Control VENDOR OR CLASS REQUEST if pUrb RtICopyMemory pTemp pTestCtrlDesc sizeof USBTESTDESC UsbBuildVendorRequest pUrb URB FUNCTION CLASS DEVICE Command sizeof struct _URB Control VENDOR OR CLASS RE
164. tus NULL free pvBuffer AfxMessageBox completed Get Command One With this definition when the Get Command One menu item is chosen the application will send the IRP Test GET CONFIG URATION DESCRIPTOR IRP to the WDM driver The driver as described in Chapter 6 will then process the IRP and generate a corresponding URB to perform the specified USB function The code examples on the enclosed diskette and in the Appendices will give you a more detailed insight into the software programs required for USB devices 87 USB Application Software WDM Driver and Firmware Examples 8 USB Application Software WDM Driver and Firmware Examples This chapter describes the USB application software WDM driver and firmware examples that are included on the enclosed diskette These examples illustrate how application software interacts and communicates with the WDM device driver of a USB device The USB device uses a 8x930Ax microcontroller with its firmware to handle USB enumeration and commands To demonstrate the examples you ll need a USB host PC and a 8x930Ax evaluation board as shown in Figure 8 1 8x930Ax Evaluation USB Kit USB host USB device Memphis Operating System 8x930Ax application software firmware WDM driver Figure 8 1 Lab setup to use the USB code examples The host PC runs on a Microsoft s Memphis Developer release build 1351 operating system which supports USB Plug and Play devic
165. uration bytes also allows you to choose the number of wait states required to interface to external memory to configure source or binary mode etc for the 8x930Ax You can select no wait state one two or three wait states to interface to external memory There is also a wait pin to provide a real time wait function to interface with slower external components The configuration bytes are located in FF FFF8H and FF FFF9H locations for the 8x930Ax with internal ROM For the ROMless version you are required to put these two configuration bytes in the highest F8 and F9 locations of external memory For example if you use a 32 Kbyte EPROM you would put the configuration bytes in the locations 7FF8H and 7FF9H and for the case of 64 Kbytes EPROM you would put the configuration bytes in FFF8H and FFF9H Chapter 4 of the 8x930Ax 8x930Hx USB Microcontroller User s Manual describes the configuration bytes in detail 39 Overview of the 8x930Ax USB Microcontroller The 8x930Ax has a 24 bit program counter and a 24 bit data pointer to address up to 256 Kbyte of addressing space We can use the double word indexing capability of the registers to address to the 256 Kbyte of address space For example MOV DR28 R4 Similarly there are EJMP addr24 and ECALL addr24 to jump or call to a subroutine pointed to by the 24 bit address addr24 respectively After chip reset the program counter of the 8x930Ax is initialized to the FFOOOOH location this
166. urationDescriptor gt wTotalLength 16 Get nonpaged pool memory for the data buffer configurationDescriptor ExAllocatepool NonPagedPool siz Now get the entire Configuration Descriptor if configurationDescriptor NULL UsbBuildGetDescriptorRequest urb 145 A WDM Driver Code Example USHORT sizeof struct URB Control DESCRIPTOR REQUEST USB CONFIGURATION DESCRIPTOR TYPE 0 0 configurationDescriptor NULL siz Get all the descriptor data NULL ntStatus Test_CallUSBD DeviceObject urb if NT_SUCCESS ntStatus else Error in getting configuration descriptor goto Exit_TestConfigureDevice Welse else Failed getting data buffer configurationDescriptor memory ntStatus STATUS NO MEMORY goto Exit_TestConfigureDevice if else else failed getting urb memory ntStatus STATUS_NO MEMORY goto Exit_TestConfigureDevice if else We have the configuration descriptor for the configuration we want Now we issue the SelectConfiguration command to get the pipes associated with this configuration if configurationDescriptor Get our pipes ntStatus Test_SelectInterfaces DeviceObject configurationDescriptor NULL Device not yet configured p At 146 Appendices Exit_TestConfigureDevice Clean up and exit this Routine if urb NULL ExFreepool urb Free urb memory At if configurationDescriptor NULL ExFreepool
167. vers I O Request Packet A data structure used to represent an I O request and to control its processing It is created by the I O manager and is passed to one or more drivers for processing When the drivers finish performing the operation the I O manager completes the I O and deletes the IRP Integrated Services Digital Network An inter nationally accepted standard for voice data and signaling using public switched telephone networks All transmissions are digital from end to end One of four USB transfer types It is used to transmit a stream of data whose timing is implied by the delivery rate Isochronous transfer provides periodic continuous communication between host and device 102 Kernel Mode kbps Little Endian Mbps Modem MSB Multitasking NACK NRZI NT Executive Object Object Manager Glossary The privileged processor mode where Windows NT system code runs A thread running in kernel mode has access to system memory and to hardware kilo bit per second 1 kbps equals 1000 bps Method of storing data that places the least significant byte of multiple byte values at lower storage address Mega bits per second Modulator Demodulator Component that converts signals between analog and digital Typically used to send digital information from a computer over a telephone network which is usually analog Most Significant Bit A processor s execution of more than one thread by c
168. wIndex 1 Get the endpoint of the stall to clear JB ACC 7 ClearlnStall For Non EPO examining the direction bit as well ClearOutStall anl EPCONO CLEAR_ OUT STALL MASK ljmp ReturnSTDSetEPCommand ClearlnStall anl EPCONO CLEAR_IN STALL MASK ljmp ReturnSTDSetEPCommand CheckSetEndpointFeature cjne A HSET FEATURE ReturnBadSTDSetEPCommand SetEndpointFeature SET ENDPOINT STALL SetEndpointStall mov A wIndex 1 Get the endpoint to stall JB ACC 7 SetInStall SetOutStall orl EPCONO SET OUT STALL MASK 120 Appendices ljmp ReturnSTDSetEPCommand SetInStall orl EPCONO HSET IN STALL MASK ljmp ReturnSTDSetEPCommand RetumBadSTDSetEPCommand push EPINDEX mov EPINDEX 401 mov TXDAT 14h mov TXCNT 01h pop EPINDEX orl EPCONO 0C0h Stall EPO ReturnSTDSetEPCommand pop EPINDEX ljmp SetUpControlWriteStatusStage for standard set device commands StandardSetDeviceCommand mov A bRequest cjne A SET_CONFIGURATION CheckSetDeviceAddress SetDeviceConfiguration SET DEVICE CONFIGURATION ljmp ReturnSTDSetDevice CheckSetDeviceAddress cjne A HSET ADDRESS ReturnBadSetDeviceCommand SET DEVICE CONFIGURATION Special case Set Address should just return The command will be executed following the status stage ljmp RetumSTDSetDevice RetumSTDSetDevice ljmp SetUpControl WriteStatusStage ReturnBadSetDeviceCommand 121 Firmware Code Example For Intel 8x930Ax USB Microcontroller
169. ynchronous mode 43 Overview of the 8x930Ax USB Microcontroller with one pin TxD pin to transmit and the other pin RxD pin to receive the data In these modes the data frame can be 10 or 11 bits one start bit eight data bits one programmable ninth bits and one stop bit The maximum programmable baud rate is 750 0 Kbaud for the 8x930Ax using rimer 2 as a baud rate generator 4 1 6 8x93QAx USB Module The on chip USB module of the 8x930Ax provides an excellent and simple interface to the USB wires The detailed connection of this USB interface is described in the Interface with the 8x930Ax section The USB module consists of a transceiver a serial bus interface engine SIE a function interface unit FIU and USB FIFOs as shown in Figure 4 4 8x930Ax Figure 4 4 The USB module of the 8x930Ax The input output pins Dean and Dmo of the transceiver enable it to connect directly with a series resistor each to the USB wires of D and D see Interface with the 8x930Ax section The SIE unit provides packet decoding generation CRC generation and checking NRZI encoding decoding and bit stuffing capabilities as required by the USB Specification The FIU provides an interface for the SIE to the FIFOs and then to the MCS 251 core of the 8x930Ax controller There are four pairs of FIFOs in the 8x930Ax corresponding to four pairs of USB endpoints 44 Step 3 Developing The Device Hardware Endpoint in bytes C 1
170. ystem functions like thread scheduling interrupt handling etc The HAL manipulates the hardware directly e Object model Windows NT uses objects to represent and manage system resources and dispense them to users Any system resource that can be shared by more than one process including files shared memory and physical devices is implemented as an object and manipulated by using object services In this fashion any changes or additions to hardware for 63 Windows NT System Overview example require only code modifications in the object and the services layer that operate the object other system codes remain the same This makes the system codes easier to maintain The operating system that uses the object model has other advantages as well gt The operating system accesses and manipulates its resources uniformly gt It simplifies the implementation of security because all objects are protected in the same way gt Objects provide a convenient and uniform paradigm for sharing resources between two or more processes Symmetric multiprocessing This model allows Windows NT to achieve maximum performance in a multi processor computing environment 6 3 1 Windows NT Structure The structure of Windows NT can be divided into two portions the user mode the Windows NT protected subsystems and the kernel mode the NT Executive as shown in Figure 6 4 The Windows NT servers run in user mode and are called the prot

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