*
* \li Series 7 USB AVRs (AT90USBxxx7)
* \li Series 6 USB AVRs (AT90USBxxx6)
+ * \li Series 4 USB AVRs (ATMEGAxxU4) - <i>See \ref SSec_Aux_Space</i>
+ * \li ATMEGA32U2 - <i>See \ref SSec_Aux_Space</i>
*
* \section Sec_Info USB Information:
*
* firmware image file, to load firmware onto the AVR.
*
* Out of the box this bootloader builds for the AT90USB1287 with an 8KB bootloader section size, and will fit
- * into 8KB of bootloader space. If you wish to alter this size and/or change the AVR model, you will need to
+ * into 6KB of bootloader space. If you wish to alter this size and/or change the AVR model, you will need to
* edit the MCU, FLASH_SIZE_KB and BOOT_SECTION_SIZE_KB values in the accompanying makefile.
*
* When the bootloader is running, the board's LED(s) will flash at regular intervals to distinguish the
*
* The current device firmware can be read from the device by reading a file from the virtual FAT filesystem.
*
+ * \warning This bootloader is currently <b>incompatible with the Apple MacOS X OS Finder GUI</b>, due to the
+ * large amount of meta files this OS attempts to write to the disk along with the new binaries. On
+ * this platform, firmwares must be copied to the disk via the Terminal application only to prevent
+ * firmware corruption.
+ *
* \section Sec_API User Application API
*
* Several user application functions for FLASH and other special memory area manipulations are exposed by the bootloader,
* #define BOOTLOADER_ADDRESS_LENGTH 4
* \endcode
*
+ * From the application the API support of the bootloader can be detected by reading the FLASH memory bytes located at address
+ * \c BOOTLOADER_MAGIC_SIGNATURE_START and comparing them to the value \c BOOTLOADER_MAGIC_SIGNATURE. The class of bootloader
+ * can be determined by reading the FLASH memory bytes located at address \c BOOTLOADER_CLASS_SIGNATURE_START and comparing them
+ * to the value \c BOOTLOADER_MASS_STORAGE_SIGNATURE. The start address of the bootloader can be retrieved by reading the bytes
+ * of FLASH memory starting from address \c BOOTLOADER_ADDRESS_START.
+ *
+ * \subsection SSec_Aux_Space Auxiliary Bootloader Section
+ * To make the bootloader function on smaller devices (those with a physical bootloader section of smaller than 6KB) a second
+ * section of memory (called the <i>Auxiliary Bootloader Section</i>) is added before the start of the real bootloader section,
+ * and is filled with a portion of the bootloader code. This allows smaller devices to run the bootloader, at the cost of an
+ * additional portion of the device's FLASH (the bootloader section size in KB subtracted from the 6KB total size). A small
+ * trampoline is inserted at the start of the auxiliary section so that the bootloader will run normally in the case of a blank
+ * application section.
+ *
+ * On devices supporting a 8KB bootloader section size, the AUX section is not created in the final binary.
+ *
* \subsection SSec_API_MemLayout Device Memory Map
* The following illustration indicates the final memory map of the device when loaded with the bootloader.
*
* | |
* | |
* | |
+ * | |
+ * +----------------------------+ FLASHEND - BOOT_SECTION_SIZE - BOOT_AUX_SECTION_SIZE
+ * | Booloader Start Trampoline |
+ * | (Not User App. Accessible) |
+ * +----------------------------+ FLASHEND - BOOT_SECTION_SIZE - BOOT_AUX_SECTION_SIZE + 4
+ * | |
+ * | Auxiliary Bootloader |
+ * | Space for Smaller Devices |
+ * | (Not User App. Accessible) |
+ * | |
* +----------------------------+ FLASHEND - BOOT_SECTION_SIZE
* | |
* | Bootloader Application |
* +----------------------------+ FLASHEND
* \endverbatim
*
- * Bootloaders reporting a device release revision number of 1.00 or greater are bootloader API enabled. From the application
- * the API support of the bootloader can be detected by reading the FLASH memory bytes located at address \c BOOTLOADER_MAGIC_SIGNATURE_START
- * and comparing them to the value \c BOOTLOADER_MAGIC_SIGNATURE. The class of bootloader can be determined by reading the
- * FLASH memory bytes located at address \c BOOTLOADER_CLASS_SIGNATURE_START and comparing them to the value \c BOOTLOADER_MASS_STORAGE_SIGNATURE.
- * The start address of the bootloader can be retrieved by reading the bytes of FLASH memory starting from address \c BOOTLOADER_ADDRESS_START.
+ * \section Sec_KnownIssues Known Issues:
+ *
+ * \par In some cases, the application is not fully loaded into the device.
+ * Write-caching on some operating systems may interfere with the normal
+ * operation of the bootloader. Write caching should be disabled when using the
+ * Mass Storage bootloader, or the file system synced via an appropriate command
+ * (such as the OS's normal disk ejection command) before disconnecting the device.
+ *
+ * \par After loading an application, it is not run automatically on startup.
+ * Some USB AVR boards ship with the BOOTRST fuse set, causing the bootloader
+ * to run automatically when the device is reset. In most cases, the BOOTRST
+ * fuse should be disabled and the HWBE fuse used instead to run the bootloader
+ * when needed.
*
* \section Sec_Options Project Options
*
*
* <table>
* <tr>
- * <td>
- * None
- * </td>
+ * <th><b>Define Name:</b></th>
+ * <th><b>Location:</b></th>
+ * <th><b>Description:</b></th>
+ * </tr>
+ * <tr>
+ * <td>NO_APP_START_ON_EJECT</td>
+ * <td>AppConfig.h</td>
+ * <td>Define to disable automatic start of the loaded application when the virtual
+ * Mass Storage disk is ejected on the host.</td>
* </tr>
* </table>
*/
projects / pub / USBasp.git / blobdiff