Bootloaders/Printer/BootloaderPrinter.txt

   1 /** \file
   2  *
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   4  *  documentation pages. It is not a project source file.
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   6
   7 /** \mainpage Printer 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)
  16  *  \li Series 2 USB AVRs (AT90USBxx2, ATMEGAxxU2)
  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>Printer Class</td>
  30  *   </tr>
  31  *   <tr>
  32  *    <td><b>USB Subclass:</b></td>
  33  *    <td>Printer Subclass</td>
  34  *   </tr>
  35  *   <tr>
  36  *    <td><b>Relevant Standards:</b></td>
  37  *    <td>USBIF Printer Class Standard</td>
  38  *   </tr>
  39  *   <tr>
  40  *    <td><b>Supported USB Speeds:</b></td>
  41  *    <td>Full Speed Mode</td>
  42  *   </tr>
  43  *  </table>
  44  *
  45  *  \section Sec_Description Project Description:
  46  *
  47  *  This bootloader enumerates to the host as a Generic Text Only Printer device, capable of reading and parsing
  48  *  "printed" plain-text Intel HEX files to load firmware onto the AVR.
  49  *
  50  *  Out of the box this bootloader builds for the AT90USB1287 with an 8KB bootloader section size, and will fit
  51  *  into 4KB of bootloader space. If you wish to alter this size and/or change the AVR model, you will need to
  52  *  edit the MCU, FLASH_SIZE_KB and BOOT_SECTION_SIZE_KB values in the accompanying makefile.
  53  *
  54  *  When the bootloader is running, the board's LED(s) will flash at regular intervals to distinguish the
  55  *  bootloader from the normal user application.
  56  *
  57  *  \section Sec_Running Running the Bootloader
  58  *
  59  *  On the USB AVR8 devices, setting the \c HWBE device fuse will cause the bootloader to run if the \c HWB pin of
  60  *  the AVR is grounded when the device is reset.
  61  *
  62  *  The are two behaviours of this bootloader, depending on the device's fuses:
  63  *
  64  *  <b>If the device's BOOTRST fuse is set</b>, the bootloader will run any time the system is reset from
  65  *  the external reset pin, unless no valid user application has been loaded. To initiate the bootloader, the
  66  *  device's external reset pin should be grounded momentarily.
  67  *
  68  *  <b>If the device's BOOTRST fuse is not set</b>, the bootloader will run only if initiated via a software
  69  *  jump, or if the \c HWB pin was low during the last device reset (if the \c HWBE fuse is set).
  70  *
  71  *  For board specific exceptions to the above, see below.
  72  *
  73  *  \subsection SSec_XPLAIN Atmel Xplain Board
  74  *  Ground the USB AVR JTAG's \c TCK pin to ground when powering on the board to start the bootloader. This assumes the
  75  *  \c HWBE fuse is cleared and the \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
  76  *
  77  *  \subsection SSec_Leonardo Arduino Leonardo Board
  78  *  Ground \c IO13 when powering the board to start the bootloader. This assumes the \c HWBE fuse is cleared and the
  79  *  \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
  80  *
  81  *  \section Sec_Installation Driver Installation
  82  *
  83  *  This bootloader uses the Generic Text-Only printer drivers inbuilt into all modern operating systems, thus no
  84  *  additional drivers need to be supplied for correct operation.
  85  *
  86  *  \section Sec_HostApp Host Controller Application
  87  *
  88  *  This bootloader is compatible with Notepad under Windows, and the command line \c lpr utility under Linux.
  89  *
  90  *  \subsection SSec_Notepad Notepad (Windows)
  91  *
  92  *  While most text applications under Windows will be compatible with the bootloader, the inbuilt Notepad utility
  93  *  is recommended as it will introduce minimal formatting changes to the output stream. To program with Notepad,
  94  *  open the target HEX file and print it to the Generic Text Only printer device the bootloader creates.
  95  *
  96  *  \subsection SSec_LPR LPR (Linux)
  97  *
  98  *  While the CUPS framework under Linux will enumerate the bootloader as a Generic Text-Only printer, many
  99  *  applications will refuse to print to the device due to the lack of rich formatting options available. As a result,
 100  *  under Linux HEX files must be printed via the low level \c lpr utility instead.
 101  *
 102  *  \code
 103  *  cat Mouse.hex | lpr
 104  *  \endcode
 105  *
 106  *  \section Sec_API User Application API
 107  *
 108  *  Several user application functions for FLASH and other special memory area manipulations are exposed by the bootloader,
 109  *  allowing the user application to call into the bootloader at runtime to read and write FLASH data.
 110  *
 111  *  By default, the bootloader API jump table is located 32 bytes from the end of the device's FLASH memory, and follows the
 112  *  following layout:
 113  *
 114  *  \code
 115  *  #define BOOTLOADER_API_TABLE_SIZE          32
 116  *  #define BOOTLOADER_API_TABLE_START         ((FLASHEND + 1UL) - BOOTLOADER_API_TABLE_SIZE)
 117  *  #define BOOTLOADER_API_CALL(Index)         (void*)((BOOTLOADER_API_TABLE_START + (Index * 2)) / 2)
 118  *
 119  *  void    (*BootloaderAPI_ErasePage)(uint32_t Address)               = BOOTLOADER_API_CALL(0);
 120  *  void    (*BootloaderAPI_WritePage)(uint32_t Address)               = BOOTLOADER_API_CALL(1);
 121  *  void    (*BootloaderAPI_FillWord)(uint32_t Address, uint16_t Word) = BOOTLOADER_API_CALL(2);
 122  *  uint8_t (*BootloaderAPI_ReadSignature)(uint16_t Address)           = BOOTLOADER_API_CALL(3);
 123  *  uint8_t (*BootloaderAPI_ReadFuse)(uint16_t Address)                = BOOTLOADER_API_CALL(4);
 124  *  uint8_t (*BootloaderAPI_ReadLock)(void)                            = BOOTLOADER_API_CALL(5);
 125  *  void    (*BootloaderAPI_WriteLock)(uint8_t LockBits)               = BOOTLOADER_API_CALL(6);
 126  *
 127  *  #define BOOTLOADER_MAGIC_SIGNATURE_START   (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 2))
 128  *  #define BOOTLOADER_MAGIC_SIGNATURE         0xDCFB
 129  *
 130  *  #define BOOTLOADER_CLASS_SIGNATURE_START   (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 4))
 131  *  #define BOOTLOADER_PRINTER_SIGNATURE       0xDF20
 132  *
 133  *  #define BOOTLOADER_ADDRESS_START           (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 8))
 134  *  #define BOOTLOADER_ADDRESS_LENGTH          4
 135  *  \endcode
 136  *
 137  *  From the application the API support of the bootloader can be detected by reading the FLASH memory bytes located at address
 138  *  \c BOOTLOADER_MAGIC_SIGNATURE_START and comparing them to the value \c BOOTLOADER_MAGIC_SIGNATURE. The class of bootloader
 139  *  can be determined by reading the FLASH memory bytes located at address \c BOOTLOADER_CLASS_SIGNATURE_START and comparing them
 140  *  to the value \c BOOTLOADER_PRINTER_SIGNATURE. The start address of the bootloader can be retrieved by reading the bytes of FLASH
 141  *  memory starting from address \c BOOTLOADER_ADDRESS_START.
 142  *
 143  *  \subsection SSec_API_MemLayout Device Memory Map
 144  *  The following illustration indicates the final memory map of the device when loaded with the bootloader.
 145  *
 146  *  \verbatim
 147  *  +----------------------------+ 0x0000
 148  *  |                            |
 149  *  |                            |
 150  *  |                            |
 151  *  |                            |
 152  *  |                            |
 153  *  |                            |
 154  *  |                            |
 155  *  |                            |
 156  *  |      User Application      |
 157  *  |                            |
 158  *  |                            |
 159  *  |                            |
 160  *  |                            |
 161  *  |                            |
 162  *  |                            |
 163  *  |                            |
 164  *  +----------------------------+ FLASHEND - BOOT_SECTION_SIZE
 165  *  |                            |
 166  *  |   Bootloader Application   |
 167  *  | (Not User App. Accessible) |
 168  *  |                            |
 169  *  +----------------------------+ FLASHEND - 96
 170  *  |   API Table Trampolines    |
 171  *  | (Not User App. Accessible) |
 172  *  +----------------------------+ FLASHEND - 32
 173  *  |    Bootloader API Table    |
 174  *  |   (User App. Accessible)   |
 175  *  +----------------------------+ FLASHEND - 8
 176  *  |   Bootloader ID Constants  |
 177  *  |   (User App. Accessible)   |
 178  *  +----------------------------+ FLASHEND
 179  *  \endverbatim
 180  *
 181  *
 182  *  \section Sec_KnownIssues Known Issues:
 183  *
 184  *  \par On Linux machines, new firmware fails to be sent to the device via CUPS.
 185  *  Only a limited subset of normal printer functionality is exposed via the
 186  *  bootloader, causing CUPS to reject print requests from applications that
 187  *  are unable to handle true plain-text printing. For best results, the low
 188  *  level \c lpr command should be used to print new firmware to the bootloader.
 189  *
 190  *  \section Sec_Options Project Options
 191  *
 192  *  The following defines can be found in this demo, which can control the demo behaviour when defined, or changed in value.
 193  *
 194  *  <table>
 195  *   <tr>
 196  *    <td>
 197  *     None
 198  *    </td>
 199  *   </tr>
 200  *  </table>
 201  */
 202