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MCHPFSUSB Firmware User's Guide

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1. FIGURE 1 6 USB CONTROL TRANSFER STATE MACHINE Setup Token Device to Host Setup Token Host to Device IN Token OUT Token I CI CD OUT Token IN Token USBCtrlEPService is called from usbdrv c It only services transactions that come through endpoint 0 It checks for a different transaction type to call appropriate handlers Endpoint 0 SETUP Endpoint 0 OUT or Endpoint 0 IN If the transfer stage is SETUP then USBCtrlTrfSetupHandler is called to service the setup packet Each USB control transfer setup packet is always 8 bytes long There are three steps in servicing a setup packet 1 The routine initializes the control transfer state machine 2 It then calls on each of the class specific request handlers in an attempt to find out if any handlers know how to service the request 3 Once all request handlers have had a chance to analyze the setup packet the function USBCtrlEPServiceComplete checks the transfer direction of the data stage to determine how to prepare endpoint 0 USBCtrlEPServiceComplete wraps the remaining tasks in servicing a setup packet Its main task is to set the endpoint controls appropriately for a given situation There are three possible outcomes Endpoint 0 is stalled if the request cannot be serviced Endpoint 0 is set up for transferring data to the host during the data stage Endpoint 0 is set up for receiving data from the host during the data sta
2. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates It is your responsibility to ensure that your application meets with your specifications MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED WRITTEN OR ORAL STATUTORY OR OTHERWISE RELATED TO THE INFORMATION INCLUDING BUT NOT LIMITED TO ITS CONDITION QUALITY PERFORMANCE MERCHANTABILITY OR FITNESS FOR PURPOSE Microchip disclaims all liability arising from this information and its use Use of Microchip devices in life support and or safety applications is entirely at the buyer s risk and the buyer agrees to defend indemnify and hold harmless Microchip from any and all damages claims suits or expenses resulting from such use No licenses are conveyed implicitly or otherwise under any Microchip intellectual property rights QUALITY MANAGEMENT SYSTEM CERTIFIED BY DNV ISO TS 16949 2002 Trademarks The Microchip name and logo the Microchip logo Accuron dsPIC KEELOQ KEELOQ logo microID MPLAB PIC PlCmicro PICSTART PRO MATE rfPIC and SmartShunt are registered trademarks of Microchip Technology Incorporated in the U S A and other countries Amp Lab FilterLab Linear Active Thermistor Migratable Memory MXDEV MXLAB SEEVAL SmartSensor and The Embedded Control Solutions Company are registered trademarks of Microchip Tec
3. MICROCHIP MCHPFSUSB Firmware User s Guide 2007 Microchip Technology Inc Note the following details of the code protection feature on Microchip devices Microchip products meet the specification contained in their particular Microchip Data Sheet Microchip believes that its family of products is one of the most secure families of its kind on the market today when used in the intended manner and under normal conditions There are dishonest and possibly illegal methods used to breach the code protection feature All of these methods to our knowledge require using the Microchip products in a manner outside the operating specifications contained in Microchip s Data Sheets Most likely the person doing so is engaged in theft of intellectual property Microchip is willing to work with the customer who is concerned about the integrity of their code Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code Code protection does not mean that we are guaranteeing the product as unbreakable Code protection is constantly evolving We at Microchip are committed to continuously improving the code protection features of our products Attempts to break Microchip s code protection feature may be a violation of the Digital Millennium Copyright Act If such acts allow unauthorized access to your software or other copyrighted work you may have a right to sue for relief under that Act
4. 44 118 921 5820 06 25 07 DS51679A page 24 2007 Microchip Technology Inc
5. FIGURE 1 1 RELATIONSHIPS BETWEEN MICROCHIP USB FRAMEWORK FILES AND A TYPICAL HID APPLICATION Program Memory main c usbdrv c usbdsc c LS USBDriverService while 1 usbctrltrf c usb9 c USBCtrlEPService HIUSBCheckStdReguest LuspstdSetCfgHandler hid c gt USBCheckHIDRequest user c L LL HIDInitEP la TX and RX gt Functions usbcfg h USB Data Memory Configuration usbmmap c USB RAM Mapping FIGURE 1 2 COMPILE TIME RELATIONSHIPS BETWEEN USB CONFIGURATION FILES User Configurable Files usbdcs c usbdsc h M na ire MAX EP NUMBER ko 5 USB USB Endpoint Buffer Descriptor Ragisters USB RAM escriptor RES i Information Configuration Endpoint sizes A Mapping Abstract Endpoint Endpoint Buffer Definitions Variables Class Specific Firmware Files hid c or cdc c etc DS51679A page 7 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework 1 2 3 Configuring MPLAB IDE for the USB Framework When setting up a project from the reference design the first thing to check is the project paths These should be updated to reflect the actual projec s root directory as needed The steps in updating the project paths will be demonstrated through an example In this example we will use the HID Mouse Reference project located in the directory C MCHPFSUSB fw HID Mouse You may need to adjust your target directories according to where the project is actually loc
6. be implemented Options for implementing power saving are discussed in Microchip application note AN950 Power Management for PIC18 USB Microcontrollers with nanoWatt Technology DS00950 Before putting a device to Sleep a wake up source must be enabled first For the USB bus activity interrupt to be a wake up source set the ACTVIE bit in the UIE register Note that the main USB interrupt in the PIE2 register must also be enabled as shown in Example 1 6 EXAMPLE 1 6 ENABLING USB SUSPEND PIR2bits USBIF 0 Make sure flag is cleared PIE2bits USBIE 1 Set USB wakeup source Sleep Goto sleep PIR2bits USBIF 0 Clear flag PIE2bits USBIE 0 Disable USB interrupt 1 3 2 2 4 USBWakeFromSuspend Function The routine is called when a bus activity interrupt is set It disables the bus activity interrupt and re enables the USB module DS51679A page 19 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework 1 3 2 2 5 USBRemoteWakeup Function When the host PC is in a low power state such as suspend to RAM it will normally continue to supply some power on the VBUS supply pin and will monitor the D and D data lines for a remote wake up signal USB peripheral devices may implement a remote wake up capability where they can send special signalling to the host indicating it should wake up and resume full power operation An example application where t
7. descriptor are the descriptor length and type The remaining lt text gt are string texts which must be in Unicode format This is achieved by declaring each character as a word type The whole text string is declared as a word array with the number of characters equal to lt size gt which must be calculated manually by counting characters and then entered into the array declaration For example if the string is USB then the string descriptor should be using index 02 rom struct byte bLength byte bDscType word string 3 sd002 sizeof sd002 DSC_STR U S B A USB project may have multiple strings The firmware supports the management of multiple strings through a look up table which is defined as rom const unsigned char rom USB SD Ptr amp sd000 amp sd001 amp sd002 The above example has 3 strings sd000 sd001 and sd002 Strings can be removed or added as needed The strings are managed by the look up table USB SD Ptr the index of the string must match the index position of the array amp sa000 must be in position USB_SD_Ptr 0 and so on The look up table USB SD Ptr is used by the USBStdGetDscHandler function in usb9 c sd000 is a specialized string descriptor It defines the language code which is usually US English 0x0409 1 3 1 2 2 Customizing usbdcs h In the header file usbdsc h variables for each of the descriptor components are named with the following conventions USB_CFG_DSC types are name
8. in the device specific data sheet to determine which modes are valid for a given device USE SELF POWER SENSE IO indicates that the microcontroller is sensing the presence of on board power through an I O pin If the target board design does not use an I O pin to detect the presence of self power this definition must be commented out USE USB BUS SENSE IO indicates that the firmware will use the pin defined in io cfg h to determine when to enable the USB module If the target board design does not use an I O pin to detect the presence of the USB bus this definition must be commented out When USE USB BUS SENSE IO is undefined the USB module will always be enabled Using this feature helps to improve the power efficiency of the system because the USB module is only enabled when the bus is present Additionally in order for the device to pass USB compliance certification all self powered devices are required to support a bus sense feature Self powered devices which do not implement this feature will fail the back drive voltage tests The USB specifications require that devices should not source current on D or D and never VBus unless the host is actively powering the VBus line A self powered device will not know when the host is actively powering VBUS and when it is acceptable to enable the D or D pull up resistor unless a bus sense feature is implemented Purely bus powered devices do not need to implement this feature and this f
9. interrupt INTCONbits RBIF 0 Clear flag INTCONbits RBIE 0 Disable port change interrupt o Clear flag 1 3 2 3 usbctrltrf c This file manages the control transfer and provides services to all USB classes that need to handle USB requests USB Chapter 9 HID CDC etc Since the control transfer service is shared among many USB classes and most transfers expand over multiple transactions it is important to keep track of which class owns the current control transfer session This is done by the use of Microchip USB ID MUID When MUID is equal to MUID_NULL it means no classes are capable of handling the request If the handler in usb9 c knows how to service a request the current control transfer session variable is updated to equal MUID_USB9 Similarly if a HID request is received then the MUID would be MUID HID The definitions for MUID are defined in usbcfg h and are only project specific This means two different projects could have different sets of MUIDs It is up to the user to manage the usage and assignment of MUID in each project in usbc g h 2007 Microchip Technology Inc DS51679A page 20 MCHPFSUSB Firmware User s Guide Each control transfer has three stages Setup Data and Status The state machine for handling different control transfer stages in Microchip USB firmware is illustrated in Figure 1 6 There are three different states WAIT SETUP CTRL TRF TX and CTRL TRF RX
10. 79A page 9 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework To use these projects with other PIC18 USB microcontrollers or circuit board platforms the following changes will be needed 1 Open the MPLAB IDE project 2 Select the microcontroller which will be used Menu bar gt Configure gt Select Device 3 Replace the linker script in the project with the appropriate device specific linker script These can be found in the 1kr directory inside the default installation directory for the C18 compiler 4 Editthe usbcfg h file by uncommenting the define statement for the demo board which will be used and comment the other choices See highlighted sec tion in Figure 1 4 This step may differ between the different projects so refer to the MCHPFSUSB release notes which are distributed with the firmware for more details about this step Although the USB specific registers are the same between the PIC18F4550 family and other PIC18 USB microcontrollers such as the PIC18F87J50 family a few differences still exist For example when configured for a PLL based oscillator mode the PIC18F4550 will power up by default with the PLL enabled On the PIC18F87J50 family of devices the PLL is initially disabled even when configured for a PLL based oscillator mode User firmware must set the OSCTUNE lt PLLEN gt bit at least two milli seconds before enabling the USB module if the USB module clock is being derive
11. MPLINK Linker MPLAB C18 Directories Trace MPASM C17 C18 Suite Directories and Search Paths Show directories for Dutput Directory Output Directory Intermediary Director Include Search Path Library Search Path Linker Script Search Path New Suite Defaults M Build Directory Policy Assemble Compile Link in the project directory Assemble Compile in source file directory link in output directory 1 2 4 Selecting the Hardware Configuration Microchip s current PIC18 USB microcontroller families share the same basic set of USB registers and names As a result the MCHPFSUSB Framework can be ported to work with the different PIC18 USB microcontroller families with little to no modification The MCHPFSUSB Framework is currently distributed as several separate projects which all share the same basic USB Chapter 9 firmware needed for device enumeration These individual projects differ in that they each include additional code to demonstrate implementation examples for specific USB device classes For example a Human Interface Device HID class USB device must support additional commands specific to the HID class specifications in addition to the Chapter 9 commands that all USB devices must support By default these projects are configured to work with the PICDEM FS USB Demo Board microchipDIRECT part number DM163025 which features the PIC18F4550 USB microcontroller DS516
12. PEMO define UCFG VAL _PUEN _TRINT FS MODE PP Uncomment only the demo board that you are using define PIC define Y if defined PIC1SF4SS0 PICDEM FS USB define USE SELF POWER SENSE IO define USE USB BUS SENSE IO elif defined PIC1S8FS87J50 FS USB PIM define USE USB BUS SENSE 10 endif DEVICE E A A a G E ee de AK Rb de de 2 tt tt tt define USB USE HID i gt Ce EEA red DS51679A page 11 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework 1 3 USB FIRMWARE IN THE FRAMEWORK The subdirectories autofiles and system contain the USB firmware source code in the framework Some of these files should never be modified while others must be edited to configure the application Each folder and its files will be discussed in details of what they do and how to modify them to match your application 1 3 1 Autofiles Directory This directory contains three key configuration files for USB operation e usbcfg h Global USB Configuration File usbdsc c USB Descriptor File e usbdsc h USB Descriptor File Header 1 3 1 1 usbefg h This header file is the most important file of the entire project It defines the endpoints mapping to their class functions It also defines the Microchip USB ID MUID number which is used to determine which USB class currently owns the control transfer in progress Finally it defines the maximum buffer size for endpoint 0
13. To centralize the configuration of important USB features all of the USB related compile time options are found here The file is constructed as a series of define compiler directives The options to configure are EPO BUFF SIZE buffer size e MAX NUM INT max MODE PP _PPBMn UCFG VAL option option2 USE SELF POWER SENSE IO USE USB BUS SENSE IO USB USE GEN or USB USE CDC or USB USE HID MAX EP NUMBER max ep EPO BUFF SIZE defines the buffer size for endpoint 0 It can have a valid value of 8 16 32 or 64 bytes This definition is used globally in the project for many things It is used during project build to allocate appropriate buffer size for endpoint 0 It is used in the USB descriptor to notify the USB host of the size of the endpoint 0 buffer It is also used during control transfer operation When defining this variable note that a low speed USB device can only use an 8 byte buffer while a full speed USB device can use an 8 16 32 or 64 byte buffer MAX NUM INT defines the size of the array which keeps track of the active alternate setting for each interface which can be switched during operation Valid values are integers 0 1 2 If a device has multiple configurations the number of interfaces from the configuration with the highest number of interfaces should be used For example a device with two configurations has three interfaces in the first configuration and two interfaces in the second In this ca
14. WARE MICROCHIP USER S GUIDE Table of Contents AKEE O EE E E T 1 Chapter 1 Using the Microchip USB Firmware Framework LAANA AAE E A A E T T 5 1 2 Overview of the Framework wewamememanamamamuwumw nana numa mwumini kinamama 5 1 3 USB Firmware in the Framework 12 DING ES Re Se eee eee A ne 23 Worldwide Sales and Service sscccccceesseeeeeeeeeeeeeeeeeeseusseneeeeseusseeesesseaeneeeeeseaees 24 2007 Microchip Technology Inc DS51679A page iii MCHPFSUSB Firmware User s Guide NOTES DS51679A page iv 2007 Microchip Technology Inc MCHPFSUSB FIRMWARE MICROCHIP USERS GUIDE Preface NOTICE TO CUSTOMERS All documentation becomes dated and this manual is no exception Microchip tools and documentation are constantly evolving to meet customer needs so some actual dialogs and or tool descriptions may differ from those in this document Please refer to our web site www microchip com to obtain the latest documentation available Documents are identified with a DS number This number is located on the bottom of each page in front of the page number The numbering convention for the DS number is DSXXXXXA where XXXXX is the document number and A is the revision level of the document For the most up to date information on development tools see the MPLAB IDE on line help Select the Help menu and then Topics to open a list of available on
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16. ated during installation To open a project workspace 1 Launch MPLAB IDE 2 From the MPLAB IDE menu bar select File gt Open Workspace 3 Navigate and select the project or workspace file C MCHPFSUSB fw HID Mouse MCHPUSB mcw or MCHPUSB mcp 4 Return to the menu bar and select Project gt Build Options gt Project The Build Options dialog appears Figure 1 3 5 Click on the Directories tab and verify the following The Output Directory and Intermediates Directory paths should point to the output folder under your root project directory The Include Path directory should point to the projec s root directory The Library Path should point to the lib directory under the C18 program folder The Linker Script Path should point to the directory of the project s linker script file Note 1 In some cases the C18 compiler may fail to compile correctly giving an error that certain header files from the mcc18 library could not be found In this case add the path C mcc18 h after the project root path in the Include Path field 2 Ifthe C18 compiler is installed in a path other than C mcc18 the actual path should be used instead SE 7 2007 Microchip Technology Inc DS51679A page 8 MCHPFSUSB Firmware User s Guide FIGURE 1 3 CONFIGURING MPLAB IDE FOR THE MICROCHIP USB FRAMEWORK Build Options For Project MCHPUSB mcp 2 x MPASM Assembler
17. ated endpoint name is then used in usbcfg h for mapping the endpoint to its function For example assume a USB device class FOO which uses one in and one out endpoint each one being 64 bytes In Example 1 2 we have chosen this class to use endpoint 1 The names are arbitrary and can be anything other than FOO For abstraction any code written for devices of this class should use the abstract definitions such as FOO BD OUT FOO BD IN and so on and not ep1Bo or ep1Bi Note that the endpoint size defined in usbcfg h is again used in usbmmap c This shows that the relationship between the two files is tightly related EXAMPLE 1 2 DEFINING THE ENDPOINTS FOR CLASS Foo define FOO_INTF_ID 0x00 define FOO UEP UEP1 define FOO BD OUT ep1Bo define FOO BD IN ep1Bi define FOO EP SIZE 64 The endpoint buffer for each USB function must be located in a dual port or dual access RAM area e g 0x400 to Ox7FF on the PIC18F4550 or 0x000 to OxF3F on the PIC18F87J50 but should not overlap with the buffer descriptor table An example declaration is volatile far unsigned char FOO EP SIZE data The volatile keyword tells the compiler not to perform any code optimization on this variable because its content could be modified by the hardware The far keyword tells the compiler that this variable is not located in the Access RAM area 0x000 to 0x05F For the variable to be globally accessible by
18. d from the PLL To accommodate these types of differences the source code for the MCHPFSUSB Framework uses if defined demo board name statements By uncommenting the define statement of step 4 the C18 compiler will be able to know which if defined demo board name statements are applicable for the demo platform device being used If developing for a non Microchip demo board platform additional changes may also be needed The example framework projects make use of the hardware features avail able on the demo boards such as LEDs push buttons temperature sensor RS 232 connector etc When developing for a different platform these aspects of the projects will either need to be replaced or removed The io cfg h file maps functions to pin names and will likely need modification 2007 Microchip Technology Inc DS51679A page 10 MCHPFSUSB Firmware User s Guide FIGURE 1 4 SELECTING THE HARDWARE PLATFORM PARTICULAR PURPOSE APPLY TO THIS SOFTWARE THE COMPANY SHALL NOT IN ANY CIRCUMSTANCES BE LIABLE FOR SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES FOR ANY REASON WHATSOEVER r HR k k k k ee o o k o o o o o ee ee ee A tt tt EE EE EE ER ifndef USBCFG H define USBCFG H AFF D E F I N I T I 0 N FRKEEEEKKEKEREEEKKKKREEEEKEKKEEREEREREEEERE f define EPO BUFF SIZE 8 f f 8 16 32 or 64 define MAK NUM INT For tracking Alternate Setting Parameter definitions are defined in usbdrv h define MODE PP _P
19. d cdxx where xx is the configuration number This number should match the actual index value of the configuration USB_INTF_DSC types are named i lt yy gt a lt zz gt where yy is the interface number and zz is the alternate interface number USB_EP_DSC types are named ep lt gt lt d gt _i lt yy gt a lt zz gt where is the endpoint number and d is the direction of transfer The interface name should also be listed as a suffix to identify which interface the endpoint belongs to Example 1 1 shows the structure in usbdsc h of a configuration descriptor This device has one configuration with two interfaces interface 0 with two endpoints in and out and interface 1 with one endpoint in The hierarchy of the descriptors shown here follows the USB specification requirement All endpoints belonging to an interface should be listed immediately after that interface EXAMPLE 1 1 DEFINING A CONFIGURATION IN USBDSC H define CFGO1 rom struct USB CFG DSC cd01 USB INTF DSC i00a00 USB EP DSC ep01o i00a00 USB EP DSC ep0li 100400 USB INTF DSC i01a00 USB EP DSC ep02i i01a00 cfg9g01 a an an an an a E DS51679A page 15 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework 1 3 1 2 3 Adding Configurations A USB device may have more than one configuration descriptor e g CFG02 CFGOS etc To add another configuration descriptor implement a new set of structures si
20. e The next parameter identifies the endpoint It takes the format _EP lt gt lt dir gt where is the endpoint number and di r is the direction of transfer The di r has the value of either OUT or IN The definitions are provided in usbdefs std dsc h The next parameter identifies the type of the endpoint Available options are _ BULK INT ISO and CTRL for Bulk Interrupt Isochronous and Control endpoints respectively The CTRL is not typically used because the default control transfer endpoint is not defined in the USB descriptors When ISO is used additional options can be ORed with it For example ISO AD FE describes the endpoint as an isochronous pipe with adaptive and feedback attributes See usbdefs std dsc h and the USB specification for details The final parameters define the maximum size of the endpoint and the polling interval o DO 2007 Microchip Technology lnc DS51679A page 14 MCHPFSUSB Firmware User s Guide The USB Descriptor String Rather than appearing as a simple string of text the descriptor is formatted in a particular data structure The string descriptor array takes the format rom struct byte bLength byte bDscType word string size sdxxx sizeof sdxxx DSC_STR lt text gt This structure provides a means for the C compiler to calculate the length of string descriptor sdxxx where xxx is the string index number The first two bytes of the
21. eature may be commented out USB_USE_GEN USB_USE_CDC and USB_USE_HID are used to indicate which USB classes should be included in the code project When each of these are defined it tells the USB global header file usb n which class specific header files to include The usb h header is used globally as the necessary include file when using the USB library If the HID class is used then hid c and hid h should also be added to the MPLAB IDE project If the CDC class is used then cdc c and cdc h should also be added to the MPLAB IDE project This definition is also used when the SET_CONFIGURATION request is received Users can modify the Modifiable Section in the USBStdSetCfgHandler function in usb9 c The calls located in the modifiable section initialize endpoints used by each specific USB class which are mapped by usbcfg h DS51679A page 13 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework MAX EP NUMBER must equal the highest endpoint number used in the project For example if the highest endpoint number used is endpoint 5 then MAX EP NUMBER should equal five This definition is used mainly in the usbmmap c to allocate the buffer descriptor registers 1 3 1 2 usbdsc c AND usbdsc h These files contain the USB descriptor information for the device The main file usbdsc c defines the descriptor itself usbdsc h defines the descriptor structure which is used to calculate the descriptor si
22. ge The data stage can be expanded over multiple USB transactions For example a USB string descriptor is allowed to be much larger than 8 bytes long If the endpoint buffer has been configured for 8 bytes maximum the entire string descriptor cannot be sent to the host in a single transaction Instead it must be split up into multiple transactions of up to 8 bytes each SS EO ZOO OEEZ SS DS51679A page 21 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework In order to handle this scenario it is important to keep track of the data source data destination data count and data type These are tracked and updated using four dedicated variables psre e pDst e wCount e the memory type flag bit usb stat ctrl trf mem which can have the value of _ROM or RAM When writing a request handler to send control transfer data from a peripheral device to a host make sure to do the following 1 Set data source For a RAM location pSrc bRam lt RAM buffer location gt For a ROM location pSrc bRom lt program memory location gt 2 Set memory source type usb stat ctrl trf mem lt ROM or RAM gt 3 Set the size of data to transfer wCount word lt size of data to transfer gt 4 The data destination IN endpoint buffer address is handled automatically by usbctrltrf c the destination is the Ctr1TrfData buffer space defined in usbmmap c When writing a request handler to receive control t
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24. his feature would typically be used would be a USB infrared remote control receiver If the user presses the power button on the remote control the USB infrared receiver could detect decode this signal and then send special signalling to the host PC to wake it up A device may send the special remote wake up signalling to the host PC by calling the USBRemoteWakeup function Example 1 7 shows sample code that would reside in the USBSuspend function which would enable both the USB and external stimulus wake up sources and call the USBRemoteWakup function if the wake up source is not USB In this example either USB traffic or the PORTB interrupt on change feature would be used to wake up the microcontroller If the microcontroller wake up source happened to be a change in the PORTB value perhaps due to a user pressing a push button on one of the PORTB pins the USBRemoteWakeup function is called and would attempt to wake up the host PC EXAMPLE 1 7 ENABLING USB REMOTE WAKE UP PIR2bits USBIF 0 Make sure flag is cleared INTCONbits RBIF 0 Make sure flag is cleared PIE2bits USBIE 1 Set USB wakeup source INTCONbits RBIE 1 Set port change wakeup source Sleep Goto sleep if INTCONbits RBIF 1 Check if the wakeup source is the port change interrupt USBRemoteWakeup If yes attempt Remote Wakeup end if PIR2bits USBIF PIE2bits USBIE 0 Disable USB
25. hnology Incorporated in the U S A Analog for the Digital Age Application Maestro CodeGuard dsPICDEM dsPICDEM net dsPICworks dsSPEAK ECAN ECONOMONITOR FanSense FlexROM fuzzyLAB In Circuit Serial Programming ICSP ICEPIC Mindi MiWi MPASM MPLAB Certified logo MPLIB MPLINK PICKkit PICDEM PICDEM net PICLAB PICtail PowerCal Powerlnfo PowerMate PowerTool REAL ICE rfLAB Select Mode Smart Serial SmartTel Total Endurance UNI O WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U S A and other countries SQTP is a service mark of Microchip Technology Incorporated in the U S A All other trademarks mentioned herein are property of their respective companies 2007 Microchip Technology Incorporated Printed in the U S A All Rights Reserved gt Printed on recycled paper Microchip received ISO TS 16949 2002 certification for its worldwide headquarters design and wafer fabrication facilities in Chandler and Tempe Arizona Gresham Oregon and design centers in California and India The Company s quality system processes and procedures are for its PIC MCUs and dsPIC DSCs KEELOQ code hopping devices Serial EEPROMs microperipherals nonvolatile memory and analog products In addition Microchip s quality system for the design and manufacture of development systems is ISO 9001 2000 certified DS51679A page ii 2007 Microchip Technology Inc AN MCHPFSUSB FIRM
26. line help files INTRODUCTION This document discusses the technical details and functionality of the MCHPFSUSB Firmware It assumes that the programmer already a Knows how to write C programs b Knows how to use the MPLAB Integrated Development Environment IDE c Understands the microcontroller data sheet for which the code is being written d Understands some basic USB concepts such as those covered in chapters 5 8 and 9 in the official USB 2 0 specifications Items discussed in this chapter include e About This Guide Recommended Reading e The Microchip Web Site Development Systems Customer Change Notification Service e Customer Support Document Revision History ABOUT THIS GUIDE Document Layout This document describes how to use the MCHPFSUSB Firmware for creating USB applications The manual layout is as follows e Chapter 1 Using the Microchip USB Firmware Framework provides an overview of the framework and how to use it in the design of new USB solutions 2007 Microchip Technology Inc DS51679A page 1 Conventions Used in this Guide Preface This manual uses the following documentation conventions DOCUMENTATION CONVENTIONS Description Represents Examples Arial font Italic characters Referenced books MPLAB IDE Users Guide Emphasized text is the only compiler Initial caps A window the Output window A dialog the Setting
27. m ilar to CFG01 to both usbdsc c and usbdsc h These will be named CF GOZ2 or CFG03 and so on Once this is done add the new configuration descriptor name cf g02 c g03 to the look up table USB CD Ptr in the same method used for man aging descriptor strings USB CD Ptr 0 isadummy place holder for configuration 0 the unconfigured state defined by the USB specification The configuration handler USBStdSetCfgHandler must also be modified to support the additional configurations 1 3 2 System Directory The project system directory contains many of the USB core function files Its structure is shown in Figure 1 5 FIGURE 1 5 DIRECTORY TREE STRUCTURE FOR THE USB FRAMEWORK C output U autofiles system C interrupt usb class O hid Q usb9 Q usbctritrf O usbdefs U usbdry In addition to the USB memory manager usbmmap c the key files discussed in this section are located in the following folders in the USB folder usb9 usb9 c and usb9 h usbctrltrf usbetrItrf c and usbetrItrf h usbdrv usbdrv c and usbdrv h usbdefs the standard definition files usbdefs epO buff h and usbdefs std dsc h 1 3 2 1 usbmmap c This file is the USB memory manager It serves as a compile time memory allocator for the USB endpoints It uses the compile time options passed from usbcfg h to instantiate endpoints and endpoint buffers Endpoints are defined using the endpoint number and the direction of transfer Fo
28. nsactions more than four times without clearing the TRNIF flag This is because the 4 level hardware FIFO stack for storing transaction completions can only be emptied one level at a time by clearing TRNIF When more than four transactions are received without TRNIF being cleared no more transactions can be processed An example of how this may happen is shown in Example 1 4 This stops the USB module from responding to any further host requests until more stack becomes available More information regarding USTAT and transaction FIFO can be found in the USB chapter of the of the microcontroller device data sheet The user s application code should not clear the TRNIF bit directly but call USBDriverService instead as in Example 1 3 and Example 1 5 Clearing the TRNIF bit directly if an endpoint 0 transaction occurs first will cause that transaction to be lost and not be serviced by the library firmware EXAMPLE 1 3 TYPICAL METHOD OF PERFORMING ONE TRANSACTION PER LOOP PSEUDO CODE main while 1 USBDriverService if mHIDTxIsBusy HIDTxReport end while end main EXAMPLE 1 4 INCORRECT METHOD OF PERFORMING MULTIPLE TRANSACTIONS PER LOOP PSEUDO CODE main while 1 USBDriverService while mHIDTxIsBusy HIDTxReport 18 Tx while mHIDTxIsBusy HIDTxReport 229 Tx while mHIDTxIsBusy HIDTxReport 374 Tx while mHIDT
29. nships cee 7 Enabling USB Remote Wake up 20 Performing One Transaction per Loop R COMEC IA ei ei cs 19 Reading Recommended 3 Ja ota ej ra pr 18 Revision History 4 TYpical sers hernie 18 S Control Transfer State Machine 21 Customer Notification Service 4 System Directory r KIA 16 Customer Support 4 U Customizing Firmware Files USONI AC ANA EAT wawa 17 Adding Configurations 16 ous 12 WS DCLG hini losa lono entres ere tie ss esras 12 ie RE Sa MARA DE MEENA Na MAE Et ET A D ST ia roh o 17 La SUR NO D NC TT 14 SPOLUD VE CSM pene Pree er o MONT oi 20 O A WASAP AL EEE ha SSD PEKNE ie ei a ees 18 ak SS rap Pl O KA O EI LEE EE I TE usbdsc c and 11 DAS Te den tn od the 14 dre Skl k pain at Za a eee nr eT USHMMA AC Hassan u Ka 16 D USBRemoteWakeup 20 Documentation USBSUSPESNGi zliav rentu al a 19 Conventions ete he 2 USBWakeFromSuspend we 19 IA WI AAA Me nt tint 1 W H Warranty Registration wwwwwwwemammiimm mimi 3 Hardware Configuration WWW Address 3 Selecting AAA AH 9 l Internet Address 3 2007 Microchip Technology Inc DS51679A page 23 MICROCHIP WORLDWIDE SALES AND SERVICE AMERICAS Corporate Office 2355 West Chandler Blvd C
30. ocontroller Configuration USB Firmware in the Framework 1 2 OVERVIEW OF THE FRAMEWORK The Microchip USB Firmware Framework is a library that can be used to create new USB applications It can be thought of as a reference design project containing the necessary firmware code for USB operation and providing a placeholder for the users code The whole code project is contained within one single root project directory with many subdirectories for source code organization The USB Framework is based on the latest versions as this is written of Microchip s development tools To provide the best level of USB application support you should verify that you have at least these revisions of the following tools before starting e MPLAB IDE v 7 61 e Microchip C18 C Compiler v 3 12 This section describes the importance in setting up the project paths and how the framework is organized 1 2 1 The Framework Directory Structure The file structure consists of a collection of subdirectories and specific files under a root project directory The root directory for a USB project may be located in any location and have any valid directory name however the subdirectories structure should always be maintained Each of the example projects use this structure The following subdirectories and files should always be present Subdirectories output Central location for output files autofiles Contains USB global configuration file and descri
31. other files its prototype should also be listed in the header file usbmmap h with an extern keyword such as extern volatile far unsigned char FOO EP SIZE data 1 3 2 2 usbdrv c This file provides low level USB services and handles all USB hardware interrupts This section describes functions which are relevant to user in details 1 3 2 2 1 USBCheckBusStatus Function This function should be called once per main loop When an I O sense pin is used to detect the attachment and detachment of a USB cable this routine enables or disables the USB module accordingly This helps increase the power efficiency of the system and is required in order for self powered devices to pass USB compliance certification If an I O sense pin is not used the define USE USB BUS SENSE IO statement in usbcfg h should be commented out This causes USBCheckBusStatus to enable the USB module after device Reset regardless of the attachment of a USB cable DS51679A page 17 2007 Microchip Technology Inc Using the Microchip USB Firmware Framework 1 3 2 2 2 USBDriverService Function This functions polls all of the USB hardware interrupt flags in the UIR and UIE registers to check if a USB event has occurred and services the event It also clears the USB transaction complete flag TRNIF which is set after each USB transaction successfully completes Issues can occur when an application tries to send or receive tra
32. ptors e system Contains USB firmware user Placeholder for the users firmware Files CleanUp bat Delete all output files in this folder and any subdirectories e io cfg h Maps pin names to pin functions this file should be modified to match each target board The default example is designed for the PICDEM FS USB demonstration board main c The file which contains main for the application MCHPUSB mcp MPLAB IDE Project file MCHPUSB mcw MPLAB IDE Workspace file 2007 Microchip Technology Inc DS51679A page 5 Using the Microchip USB Firmware Framework 1 2 2 The Framework Logical Structure The USB Firmware Framework provides a set of modular firmware interfaces that han dle most of the work for implementing USB communications Figure 1 1 shows a typical USB program flow Each firmware reference project is written to have a cooperative multitasking environment thus no blocking functions should be implemented The main function is an infinite while loop that services different tasks These can be logically thought of as either a USB task or a user task USB tasks are handled by USBDriverService which polls and services all USB hardware interrupts When a control endpoint transaction is received USBCtrlEPService is called All transfers over the default control endpoints must follow the control transfer protocol as described in the USB specification The control transfer service is provided by function
33. r simplicity usbmmap c only uses the endpoint number in the BDT register allocation scheme This means if usbcfg h states that the MAX EP NUMBER is number 1 then four BDTs will be instantiated one each for endpoint 0 in and endpoint 0 out which must always be instantiated for control transfer by default and one of each set for endpoint 1 in and endpoint 1 out The naming convention for instantiating a BDT is ep lt gt B lt d gt where is the endpoint number and dis the direction of transfer which could be either lt i gt or lt o gt 2007 Microchip Technology Inc DS51679A page 16 MCHPFSUSB Firmware User s Guide The USB memory manager uses MAX EP NUMBER as defined in usbcfg nh to define the endpoints to be instantiated This represents the highest endpoint number to be allocated not how many endpoints are used Since the BDTs for endpoints have hardware assigned addresses in Bank 4 setting this value too high may lead to ineffi cient use of data RAM For example if an application uses only endpoints EPO and EP4 then the MAX_EP_NUMBER is 4 and not 2 The in between endpoint BDTs in this example EP1 EP2 and EP3 go unused and the 24 bytes of memory associated with them are wasted This assumes Ping Pong Buffer mode 0 which assigns 4 bytes to each BDT and one BDT to the in and out endpoints for each endpoint It does not make much sense to skip endpoints but the final decision lies with the user The instanti
34. ransfer data from a host over multiple transactions make sure to do the following 1 Setdata destination pDst bRam lt RAM buffer location gt Note that the memory destination type has to always be RAM 2 Initialize the receive counter wCount word to zero 3 The data source OUT endpoint buffer address is handled automatically by usbctrltrf c the source is the CtrlTrfData buffer space defined in usbmmap c Once the status stage is complete the control transfer session owner determined by the MUID value can process the received data The data destination is defined in the setup stage and the length of received data is stored in wCount word 1 3 2 4 usb9 c This file handles standard USB reguests as defined in Chapter 9 of the USB specifica tion and handles the enumeration process The function of interest in this file is USBStdSetCfgHandler which users must modify to match the application s configuration setup and behavior 2007 Microchip Technology lnc DS51679A page 22 MICROCHIP MCHPFSUSB FIRMWARE USERS GUIDE Index A M Autofiles Directory 12 Microchip Internet Web Site 3 c Microchip USB Firmware Framework 5 Configuring MPLAB IDE wwwwwwmwmmam 8 Code Examples Wa Directory Structure 5 Defining a Configuration in usbdsc h 15 Logical Structure 6 Defining the Endpoints for Class Foo 17 Runtime Relatio
35. s dialog A menu selection select Enable Programmer Quotes A field name in a window or __ Save project before build dialog Underlined italic text with A menu path File gt Save right angle bracket Bold characters A dialog button Click OK A tab Click the Power tab bnnnn A binary number where n is a 00100 b10 digit Text in angle brackets lt gt A key on the keyboard Press lt Enter gt lt F1 gt Courier New font Plain Courier New Sample source code define START Filenames autoexec bat File paths c mcci8 h Keywords _asm endasm static Command line options Opa Opa Bit values 0 5 T Italic Courier New A variable argument file o where file can be any valid filename Oxnnnn A hexadecimal number where nis a hexadecimal digit OxFFFF 0x007A Square brackets Optional arguments mcc18 options file options Curly brackets and pipe character Choice of mutually exclusive arguments an OR selection errorlevel 0 1 Ellipses Replaces repeated text var_name Represents code supplied by user var_name void main void 2007 Microchip Technology Inc DS51679A page 2 MCHPFSUSB Firmware Users Guide RECOMMENDED READING This user s guide describes how to use the MCHPFSUSB Firmware Other useful documents are listed below The following documents are a
36. s in usbctrltrf c The first stage of all control transfers arrive as a request A USB request can be either standard or class specific A standard request is serviced by the USBCheckStdRequest which handles the reguired reguests as specified in Chapter 9 of the USB specification A class specific reguest must be handled by the firmware file that knows how to service it Examples of device classes are Human Interface Device HID and Communication Device Class CDC The example in Figure 1 1 shows HID it could refer to any other device class just as easily The handlers for a class specific reguest should be contained in the specific device class firmware file such as hid c or cdc c The naming scheme for a function that services a class specific reguest is USBCheck lt class name gt Reguest where lt class name gt can be any class specific names The USB enumeration process is handled mainly in usb9 c One of the most important steps in the enumeration process is the handling of a SET CONFIGURATION request which is done by USBStdSetCfgHandler This function can be modified by the user to call the appropriate functions to initialize the application endpoints Each specific device class firmware should have one endpoint initialization routine The nam ing convention for this function is lt class name gt InitEP where lt class name gt can be any device class names An example is HIDInitEP which contains example code on how to ini
37. se MAX_NUM_INT should be three MODE_PP defines the Ping Pong Buffer mode to be used during run time The function of each mode is explained in the USB chapter of the device data sheet Note The current version of the firmware only supports PPBMO mode 2007 Microchip Technology Inc DS51679A page 12 MCHPFSUSB Firmware User s Guide UCFG VAL defines the initial value for the UCFG Special Function Register The allowed values are e LSor FS Select Low or Full Speed mode e _TRINT or TREXT Select Internal or External Transceiver mode e _PUEN Use internal USB pull up resistor e _OEMON Use SIE output indicator e _UTEYE Enable eye pattern test output The options can be ORed together for example define UCFG VAL PUEN TRINT FS This value is used by the firmware framework to initialize the UCFG register A full explanation of the options can be found in the description of the UCFG register in the USB chapter of the device data sheet Note 1 Ifthe LS option is selected the device clock configuration must be changed to support low speed operation Refer to the device data sheet for additional information 2 The UTEYE option is used only for device testing and never in live appli cations When _UTEYE is enabled the device transmits continuously Do not plug the device to a USB host when the option is enabled 3 Notall PIC18 USB microcontrollers support all of the listed settings Refer to the USB chapter
38. test software releases and archived software General Technical Support Freguently Asked Guestions FAG technical support reguests online discussion groups Microchip consultant program member listing Business of Microchip Product selector and ordering guides latest Microchip press releases listing of seminars and events listings of Microchip sales offices distributors and factory representatives DS51679A page 3 2007 Microchip Technology Inc Preface DEVELOPMENT SYSTEMS CUSTOMER CHANGE NOTIFICATION SERVICE Microchip s customer notification service helps keep customers current on Microchip products Subscribers will receive e mail notification whenever there are changes updates revisions or errata related to a specified product family or development tool of interest To register access the Microchip web site at www microchip com click on Customer Change Notification and follow the registration instructions The Development Systems product group categories are Compilers The latest information on Microchip C compilers and other language tools These include the MPLAB C17 MPLAB C18 and MPLAB C30 C compilers MPASM and MPLAB ASM30 assemblers MPLINK and MPLAB LINK30 object linkers and MPLIB and MPLAB LIB30 object librarians Emulators The latest information on Microchip in circuit emulators This includes the MPLAB ICE 2000 and MPLAB ICE 4000 In Circuit Debuggers The latest informa
39. tialize a group of endpoints that are used in the class Users should take care to check which configuration index is being asked to be set by the USB host A device can have multiple configurations and not all interfaces may be the same across different configurations The user s application code is also called from the main program loop it resides under the default function name ProcessIO When the application needs to send or receive a data packet it can call a prewritten function that services the transmit or receive functionality which is declared in the class specific firmware code such as HIDRxReport and HIDTxReport USB device configuration is also handled in a modular manner by modifying variables in a small number of files the information is then made globally available at compile time The files are tightly interdependent and pass information between themselves during compile time to create the complete USB configuration The relationships are shown in Figure 1 2 Customizing the configuration files is discussed in Section 1 3 USB Firmware in the Framework 2007 Microchip Technology Inc DS51679A page 6 MCHPFSUSB Firmware User s Guide
40. tion on the Microchip in circuit debugger MPLAB ICD 2 MPLAB IDE The latest information on Microchip MPLAB IDE the Windows Integrated Development Environment for development systems tools This list is focused on the MPLAB IDE MPLAB SIM and MPLAB SIM30 simulators MPLAB IDE Project Manager and general editing and debugging features Programmers The latest information on Microchip programmers These include the MPLAB PM3 and PRO MATE II device programmers and the PICSTART Plus development programmer CUSTOMER SUPPORT Users of Microchip products can receive assistance through several channels Distributor or Representative e Local Sales Office Field Application Engineer FAE Technical Support Customers should contact their distributor representative or field application engineer FAE for support Local sales offices are also available to help customers A listing of sales offices and locations is included in the back of this document Technical support is available through the web site at http support microchip com DOCUMENT REVISION HISTORY Revision A July 2007 Initial Release of this Document 2007 Microchip Technology Inc DS51679A page 4 MCHPFSUSB FIRMWARE MICROCHIP USERS GUIDE Chapter 1 Using the Microchip USB Firmware Framework 1 1 HIGHLIGHTS The items discussed in this chapter are e Overview of the Framework Configuring MPLAB IDE for the Framework Selecting the Micr
41. vailable and recommended as supplemental reference resources MCHPFSUSB Firmware Release Notes As new versions of the MCHPFSUSB Firmware are developed they will be distributed along with release notes that may cover specific and key items not necessarily covered in this User s Guide When new versions are released they will be posted at the Microchip USB design center http www microchip com usb click on the Full Speed USB Solutions link PICDEM FS USB Demonstration Board User s Guide DS51526 PIC18F87J50 FS USB Plug In Module User s Guide DS51678 Official USB 2 0 Specifications Chapter 9 in the official USB 2 0 specifications covers the commands that all USB peripheral devices must support This chapter is especially important as it strongly influences the requirements of USB firmware Chapters 5 and 8 also provide useful information regarding how data moves across the USB The official USB specifications can be downloaded from the USB Implementers Forum web site http www usb org THE MICROCHIP WEB SITE Microchip provides online support via our WWW site at www microchip com This web site is used as a means to make files and information easily available to customers Accessible by using your favorite Internet browser the web site contains the following information Product Support Data sheets and errata application notes and sample programs design resources users guides and hardware support documents la
42. xIsBusy HIDTxReport 4 Tx while mHIDTxIsBusy This will never turn false because the USTAT FIFO is full HIDTxReport 5 Tx Unreachable cod end while end main 2007 Microchip Technology Inc DS51679A page 18 MCHPFSUSB Firmware User s Guide EXAMPLE 1 5 CORRECT METHOD OF PERFORMING MULTIPLE TRANSACTIONS PER LOOP PSEUDO CODE main while 1 USBDriverService while mHIDTxIsBusy HIDTxReport 15 Tx USBDriverService while mHIDTxIsBusy HIDTxReport 204 Tx USBDriverService while mHIDTxIsBusy HIDTxReport 374 Tx USBDriverService while mHIDTxIsBusy HIDTxReport 4 Tx USBDriverService while mHIDTxIsBusy HIDTxReport 5 Tx USBDriverService other application code end while end main 1 3 2 2 3 USBSuspend Function This routine first puts the USB module into Suspended mode and enables the USB bus activity interrupt Additionally there is a user modifiable section for implementing power saving schemes In order to pass USB compliance testing devices must con sume no more than 500 LA or 2 5 mA depends on configuration see official USB specifications from VBUS when the device is in the USB suspend state This user modifiable section would be where clock switching executing the SLEEP instruction or other forms of power management should
43. ze with the sizeof statement When a descriptor is added or removed from the main configuration descriptor i e CFG01 the user must also change the descriptor structure defined in usbdsc h A typical configuration descriptor consists of these components At least one configuration descriptor USB CFG DSC One or more interface descriptors USB_INTF_DSC One or more endpoint descriptors USB EP DSC In addition there is usually a descriptor string that provides a plain text description of the device 1 3 1 2 1 Customizing usbdsc c The version of usbdsc c included with the Framework Firmware indicates which parameters must be defined and can serve as a template for developing new device descriptors Most items should be self explanatory but some options are not explained in the file s comments and are expanded upon below e USB CFG DSC The configuration attribute the item immediately following the string index must always have the DEFAULT definition at the minimum Two additional options _SELF and RWU can be ORed with DEFAULT SELF tells the USB host that this device is self powered while _RWU tells the USB host that the device supports remote wake up Definitions for these options are provided in usbdefs std dsc h e USB EP DSC An endpoint descriptor has a form similar to sizeof USB EP DSC DSC EP EP01 OUT BULK 64 0x00 The first two parameters specify the length of this endpoint descriptor 7 and the descriptor typ

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