Bootloaders/MassStorage/BootloaderMassStorage.txt

   1 /** \file
   2  *
   3  *  This file contains special DoxyGen information for the generation of the main page and other special
   4  *  documentation pages. It is not a project source file.
   5  */
   6
   7 /** \mainpage Mass Storage Class USB AVR Bootloader
   8  *
   9  *  \section Sec_Compat Demo Compatibility:
  10  *
  11  *  The following list indicates what microcontrollers are compatible with this demo.
  12  *
  13  *  \li Series 7 USB AVRs (AT90USBxxx7)
  14  *  \li Series 6 USB AVRs (AT90USBxxx6)
  15  *  \li Series 4 USB AVRs (ATMEGAxxU4) - <i>See \ref SSec_Aux_Space</i>
  16  *  \li ATMEGA32U2 - <i>See \ref SSec_Aux_Space</i>
  17  *
  18  *  \section Sec_Info USB Information:
  19  *
  20  *  The following table gives a rundown of the USB utilization of this demo.
  21  *
  22  *  <table>
  23  *   <tr>
  24  *    <td><b>USB Mode:</b></td>
  25  *    <td>Device</td>
  26  *   </tr>
  27  *   <tr>
  28  *    <td><b>USB Class:</b></td>
  29  *    <td>Mass Storage Device</td>
  30  *   </tr>
  31  *   <tr>
  32  *    <td><b>USB Subclass:</b></td>
  33  *    <td>Bulk-Only Transport</td>
  34  *   </tr>
  35  *   <tr>
  36  *    <td><b>Relevant Standards:</b></td>
  37  *    <td>USBIF Mass Storage Standard \n
  38  *        USB Bulk-Only Transport Standard \n
  39  *        SCSI Primary Commands Specification \n
  40  *        SCSI Block Commands Specification</td>
  41  *   </tr>
  42  *   <tr>
  43  *    <td><b>Supported USB Speeds:</b></td>
  44  *    <td>Full Speed Mode</td>
  45  *   </tr>
  46  *  </table>
  47  *
  48  *  \section Sec_Description Project Description:
  49  *
  50  *  This bootloader enumerates to the host as a Mass Storage device, capable of reading and writing a new binary
  51  *  firmware image file, to load firmware onto the AVR.
  52  *
  53  *  Out of the box this bootloader builds for the AT90USB1287 with an 8KB bootloader section size, and will fit
  54  *  into 6KB of bootloader space. If you wish to alter this size and/or change the AVR model, you will need to
  55  *  edit the MCU, FLASH_SIZE_KB and BOOT_SECTION_SIZE_KB values in the accompanying makefile.
  56  *
  57  *  When the bootloader is running, the board's LED(s) will flash at regular intervals to distinguish the
  58  *  bootloader from the normal user application.
  59  *
  60  *  \warning <b>THIS BOOTLOADER IS NOT SECURE.</b> Malicious entities can recover written data, even if the device
  61  *           lockbits are set.
  62  *
  63  *  \section Sec_Installation Driver Installation
  64  *
  65  *  This bootloader uses the Mass Storage drivers inbuilt into all modern operating systems, thus no additional
  66  *  drivers need to be supplied for correct operation.
  67  *
  68  *  \section Sec_HostApp Host Controller Application
  69  *
  70  *  This bootloader is compatible with all operating systems that support the FAT12 file system format. To reprogram the
  71  *  device, overwrite a file stored on the virtual FAT filesystem with a new binary (BIN format) image. Remember to safely
  72  *  remove your device from the host using the host OS's ejection APIs, to ensure all data is correctly flushed to the
  73  *  bootloader's virtual filesystem and not cached in the OS's file system driver.
  74  *
  75  *  The current device firmware can be read from the device by reading a file from the virtual FAT filesystem.
  76  *
  77  *  \warning This bootloader is currently <b>incompatible with the Apple MacOS X OS Finder GUI</b>, due to the
  78  *           large amount of meta files this OS attempts to write to the disk along with the new binaries. On
  79  *           this platform, firmwares must be copied to the disk via the Terminal application only to prevent
  80  *           firmware corruption.
  81  *
  82  *  \section Sec_API User Application API
  83  *
  84  *  Several user application functions for FLASH and other special memory area manipulations are exposed by the bootloader,
  85  *  allowing the user application to call into the bootloader at runtime to read and write FLASH data.
  86  *
  87  *  By default, the bootloader API jump table is located 32 bytes from the end of the device's FLASH memory, and follows the
  88  *  following layout:
  89  *
  90  *  \code
  91  *  #define BOOTLOADER_API_TABLE_SIZE          32
  92  *  #define BOOTLOADER_API_TABLE_START         ((FLASHEND + 1UL) - BOOTLOADER_API_TABLE_SIZE)
  93  *  #define BOOTLOADER_API_CALL(Index)         (void*)((BOOTLOADER_API_TABLE_START + (Index * 2)) / 2)
  94  *
  95  *  void    (*BootloaderAPI_ErasePage)(uint32_t Address)               = BOOTLOADER_API_CALL(0);
  96  *  void    (*BootloaderAPI_WritePage)(uint32_t Address)               = BOOTLOADER_API_CALL(1);
  97  *  void    (*BootloaderAPI_FillWord)(uint32_t Address, uint16_t Word) = BOOTLOADER_API_CALL(2);
  98  *  uint8_t (*BootloaderAPI_ReadSignature)(uint16_t Address)           = BOOTLOADER_API_CALL(3);
  99  *  uint8_t (*BootloaderAPI_ReadFuse)(uint16_t Address)                = BOOTLOADER_API_CALL(4);
 100  *  uint8_t (*BootloaderAPI_ReadLock)(void)                            = BOOTLOADER_API_CALL(5);
 101  *  void    (*BootloaderAPI_WriteLock)(uint8_t LockBits)               = BOOTLOADER_API_CALL(6);
 102  *
 103  *  #define BOOTLOADER_MAGIC_SIGNATURE_START   (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 2))
 104  *  #define BOOTLOADER_MAGIC_SIGNATURE         0xDCFB
 105  *
 106  *  #define BOOTLOADER_CLASS_SIGNATURE_START   (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 4))
 107  *  #define BOOTLOADER_MASS_STORAGE_SIGNATURE  0xDF30
 108  *
 109  *  #define BOOTLOADER_ADDRESS_START           (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 8))
 110  *  #define BOOTLOADER_ADDRESS_LENGTH          4
 111  *  \endcode
 112  *
 113  *  From the application the API support of the bootloader can be detected by reading the FLASH memory bytes located at address
 114  *  \c BOOTLOADER_MAGIC_SIGNATURE_START and comparing them to the value \c BOOTLOADER_MAGIC_SIGNATURE. The class of bootloader
 115  *  can be determined by reading the FLASH memory bytes located at address \c BOOTLOADER_CLASS_SIGNATURE_START and comparing them
 116  *  to the value \c BOOTLOADER_MASS_STORAGE_SIGNATURE. The start address of the bootloader can be retrieved by reading the bytes
 117  *  of FLASH memory starting from address \c BOOTLOADER_ADDRESS_START.
 118  *
 119  *  \subsection SSec_Aux_Space Auxiliary Bootloader Section
 120  *  To make the bootloader function on smaller devices (those with a physical bootloader section of smaller than 6KB) a second
 121  *  section of memory (called the <i>Auxiliary Bootloader Section</i>) is added before the start of the real bootloader section,
 122  *  and is filled with a portion of the bootloader code. This allows smaller devices to run the bootloader, at the cost of an
 123  *  additional portion of the device's FLASH (the bootloader section size in KB subtracted from the 6KB total size). A small
 124  *  trampoline is inserted at the start of the auxiliary section so that the bootloader will run normally in the case of a blank
 125  *  application section.
 126  *
 127  *  On devices supporting a 8KB bootloader section size, the AUX section is not created in the final binary.
 128  *
 129  *  \subsection SSec_API_MemLayout Device Memory Map
 130  *  The following illustration indicates the final memory map of the device when loaded with the bootloader.
 131  *
 132  *  \verbatim
 133  *  +----------------------------+ 0x0000
 134  *  |                            |
 135  *  |                            |
 136  *  |                            |
 137  *  |                            |
 138  *  |                            |
 139  *  |                            |
 140  *  |                            |
 141  *  |                            |
 142  *  |      User Application      |
 143  *  |                            |
 144  *  |                            |
 145  *  |                            |
 146  *  |                            |
 147  *  |                            |
 148  *  |                            |
 149  *  |                            |
 150  *  |                            |
 151  *  +----------------------------+ FLASHEND - BOOT_SECTION_SIZE - BOOT_AUX_SECTION_SIZE
 152  *  | Booloader Start Trampoline |
 153  *  | (Not User App. Accessible) |
 154  *  +----------------------------+ FLASHEND - BOOT_SECTION_SIZE - BOOT_AUX_SECTION_SIZE + 4
 155  *  |                            |
 156  *  |     Auxiliary Bootloader   |
 157  *  |  Space for Smaller Devices |
 158  *  | (Not User App. Accessible) |
 159  *  |                            |
 160  *  +----------------------------+ FLASHEND - BOOT_SECTION_SIZE
 161  *  |                            |
 162  *  |   Bootloader Application   |
 163  *  | (Not User App. Accessible) |
 164  *  |                            |
 165  *  +----------------------------+ FLASHEND - 96
 166  *  |   API Table Trampolines    |
 167  *  | (Not User App. Accessible) |
 168  *  +----------------------------+ FLASHEND - 32
 169  *  |    Bootloader API Table    |
 170  *  |   (User App. Accessible)   |
 171  *  +----------------------------+ FLASHEND - 8
 172  *  |   Bootloader ID Constants  |
 173  *  |   (User App. Accessible)   |
 174  *  +----------------------------+ FLASHEND
 175  *  \endverbatim
 176  *
 177  *  \section Sec_KnownIssues Known Issues:
 178  *
 179  *  \par In some cases, the application is not fully loaded into the device.
 180  *  Write-caching on some operating systems may interfere with the normal
 181  *  operation of the bootloader. Write caching should be disabled when using the
 182  *  Mass Storage bootloader, or the file system synced via an appropriate command
 183  *  (such as the OS's normal disk ejection command) before disconnecting the device.
 184  *
 185  *  \par After loading an application, it is not run automatically on startup.
 186  *  Some USB AVR boards ship with the BOOTRST fuse set, causing the bootloader
 187  *  to run automatically when the device is reset. In most cases, the BOOTRST
 188  *  fuse should be disabled and the HWBE fuse used instead to run the bootloader
 189  *  when needed.
 190  *
 191  *  \section Sec_Options Project Options
 192  *
 193  *  The following defines can be found in this demo, which can control the demo behaviour when defined, or changed in value.
 194  *
 195  *  <table>
 196  *   <tr>
 197  *    <th><b>Define Name:</b></th>
 198  *    <th><b>Location:</b></th>
 199  *    <th><b>Description:</b></th>
 200  *   </tr>
 201  *   <tr>
 202  *    <td>NO_APP_START_ON_EJECT</td>
 203  *    <td>AppConfig.h</td>
 204  *    <td>Define to disable automatic start of the loaded application when the virtual
 205  *        Mass Storage disk is ejected on the host.</td>
 206  *   </tr>
 207  *  </table>
 208  */
 209