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qmk_firmware/Bootloaders/CDC/BootloaderCDC.txt
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/** \file
*
* This file contains special DoxyGen information for the generation of the main page and other special
* documentation pages. It is not a project source file.
*/
/** \mainpage CDC Class USB AVR Bootloader
*
* \section Sec_Compat Demo Compatibility:
*
* The following list indicates what microcontrollers are compatible with this demo.
*
* \li Series 7 USB AVRs (AT90USBxxx7)
* \li Series 6 USB AVRs (AT90USBxxx6)
* \li Series 4 USB AVRs (ATMEGAxxU4)
* \li Series 2 USB AVRs (AT90USBxx2, ATMEGAxxU2)
*
* \section Sec_Info USB Information:
*
* The following table gives a rundown of the USB utilization of this demo.
*
* <table>
* <tr>
* <td><b>USB Mode:</b></td>
* <td>Device</td>
* </tr>
* <tr>
* <td><b>USB Class:</b></td>
* <td>Communications Device Class (CDC)</td>
* </tr>
* <tr>
* <td><b>USB Subclass:</b></td>
* <td>Abstract Control Model (ACM)</td>
* </tr>
* <tr>
* <td><b>Relevant Standards:</b></td>
* <td>USBIF CDC Class Standard</td>
* </tr>
* <tr>
* <td><b>Supported USB Speeds:</b></td>
* <td>Full Speed Mode</td>
* </tr>
* </table>
*
* \section Sec_Description Project Description:
*
* This bootloader enumerates to the host as a CDC Class device (virtual serial port), allowing for AVR109
* protocol compatible programming software 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 4KB 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
* bootloader from the normal user application.
*
* \warning <b>THIS BOOTLOADER IS NOT SECURE.</b> Malicious entities can recover written data, even if the device
* lockbits are set.
*
* \section Sec_Running Running the Bootloader
*
* On the USB AVR8 devices, setting the \c HWBE device fuse will cause the bootloader to run if the \c HWB pin of
* the AVR is grounded when the device is reset.
*
* The are two behaviours of this bootloader, depending on the device's fuses:
*
* <b>If the device's BOOTRST fuse is set</b>, the bootloader will run any time the system is reset from
* the external reset pin, unless no valid user application has been loaded. To initiate the bootloader, the
* device's external reset pin should be grounded momentarily.
*
* <b>If the device's BOOTRST fuse is not set</b>, the bootloader will run only if initiated via a software
* jump, or if the \c HWB pin was low during the last device reset (if the \c HWBE fuse is set).
*
* For board specific exceptions to the above, see below.
*
* \subsection SSec_XPLAIN Atmel Xplain Board
* Ground the USB AVR JTAG's \c TCK pin to ground when powering on the board to start the bootloader. This assumes the
* \c HWBE fuse is cleared and the \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
*
* \subsection SSec_Leonardo Arduino Leonardo Board
* Ground \c IO13 when powering the board to start the bootloader. This assumes the \c HWBE fuse is cleared and the
* \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
*
* \section Sec_Installation Driver Installation
*
* After running this bootloader for the first time on a new computer, you will need to supply the .INF
* file located in this bootloader project's directory as the device's driver when running under Windows.
* This will enable Windows to use its inbuilt CDC drivers, negating the need for custom drivers for the
* device. Other Operating Systems should automatically use their own inbuilt CDC-ACM drivers.
*
* \section Sec_HostApp Host Controller Application
*
* This bootloader is compatible with the open source application AVRDUDE, Atmel's AVRPROG, or other
* applications implementing the AVR109 protocol, which is documented on the Atmel website as an application
* note.
*
* \subsection SSec_AVRDude AVRDUDE (Windows, Mac, Linux)
*
* AVRDude is a free, cross-platform and open source command line programmer for Atmel and third party AVR
* programmers. It is available on the the Windows platform as part of the "WinAVR" package, or on other systems
* either from a build from the official source code, or in many distributions as a precompiled binary package.
*
* To load a new HEX file with AVRDude, specify "AVR109" as the programmer, with the allocated COM port. On Windows
* platforms this will be a COMx port name:
* \code
* avrdude -c AVR109 -p at90usb1287 -P COM0 -U flash:w:Mouse.hex
* \endcode
*
* On Linux systems, this will typically be a /dev/ttyACMx port name:
* \code
* avrdude -c AVR109 -p at90usb1287 -P /dev/ttyACM0 -U flash:w:Mouse.hex
* \endcode
*
* Refer to the AVRDude project documentation for additional usage instructions.
*
* \section Sec_API User Application API
*
* Several user application functions for FLASH and other special memory area manipulations are exposed by the bootloader,
* allowing the user application to call into the bootloader at runtime to read and write FLASH data.
*
* By default, the bootloader API jump table is located 32 bytes from the end of the device's FLASH memory, and follows the
* following layout:
*
* \code
* #define BOOTLOADER_API_TABLE_SIZE 32
* #define BOOTLOADER_API_TABLE_START ((FLASHEND + 1UL) - BOOTLOADER_API_TABLE_SIZE)
* #define BOOTLOADER_API_CALL(Index) (void*)((BOOTLOADER_API_TABLE_START + (Index * 2)) / 2)
*
* void (*BootloaderAPI_ErasePage)(uint32_t Address) = BOOTLOADER_API_CALL(0);
* void (*BootloaderAPI_WritePage)(uint32_t Address) = BOOTLOADER_API_CALL(1);
* void (*BootloaderAPI_FillWord)(uint32_t Address, uint16_t Word) = BOOTLOADER_API_CALL(2);
* uint8_t (*BootloaderAPI_ReadSignature)(uint16_t Address) = BOOTLOADER_API_CALL(3);
* uint8_t (*BootloaderAPI_ReadFuse)(uint16_t Address) = BOOTLOADER_API_CALL(4);
* uint8_t (*BootloaderAPI_ReadLock)(void) = BOOTLOADER_API_CALL(5);
* void (*BootloaderAPI_WriteLock)(uint8_t LockBits) = BOOTLOADER_API_CALL(6);
*
* #define BOOTLOADER_MAGIC_SIGNATURE_START (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 2))
* #define BOOTLOADER_MAGIC_SIGNATURE 0xDCFB
*
* #define BOOTLOADER_CLASS_SIGNATURE_START (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 4))
* #define BOOTLOADER_CDC_SIGNATURE 0xDF00
*
* #define BOOTLOADER_ADDRESS_START (BOOTLOADER_API_TABLE_START + (BOOTLOADER_API_TABLE_SIZE - 8))
* #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_CDC_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_API_MemLayout Device Memory Map
* The following illustration indicates the final memory map of the device when loaded with the bootloader.
*
* \verbatim
* +----------------------------+ 0x0000
* | |
* | |
* | |
* | |
* | |
* | |
* | |
* | |
* | User Application |
* | |
* | |
* | |
* | |
* | |
* | |
* | |
* +----------------------------+ FLASHEND - BOOT_SECTION_SIZE
* | |
* | Bootloader Application |
* | (Not User App. Accessible) |
* | |
* +----------------------------+ FLASHEND - 96
* | API Table Trampolines |
* | (Not User App. Accessible) |
* +----------------------------+ FLASHEND - 32
* | Bootloader API Table |
* | (User App. Accessible) |
* +----------------------------+ FLASHEND - 8
* | Bootloader ID Constants |
* | (User App. Accessible) |
* +----------------------------+ FLASHEND
* \endverbatim
*
* \section Sec_KnownIssues Known Issues:
*
* \par On Linux machines, the CDC bootloader is unstable or inaccessible.
* A change to the \c ModemManager module in many Linux distributions causes
* this module to try to take control over inserted CDC devices, corrupting the
* datastream. A UDEV rule is required to prevent this.
* See <a href=https://groups.google.com/d/msg/lufa-support/CP9cy2bc8yo/kBqsOu-RBeMJ>here</a> for resolution steps.
* If the issue still persists then uninstall modemmanager by executing <tt>sudo apt-get remove modemmanager</tt>, or
* the equivalent using your chosen distribution's package manager.
*
* \par On Linux machines, the CDC bootloader is inaccessible.
* On many Linux systems, non-root users do not have automatic access to newly
* inserted CDC devices. Root privileges or a UDEV rule is required to gain
* access.
* See <a href=https://groups.google.com/d/msg/lufa-support/CP9cy2bc8yo/kBqsOu-RBeMJ>here</a> for resolution steps.
*
* \section Sec_Options Project Options
*
* The following defines can be found in this demo, which can control the demo behaviour when defined, or changed in value.
*
* <table>
* <tr>
* <th><b>Define Name:</b></th>
* <th><b>Location:</b></th>
* <th><b>Description:</b></th>
* </tr>
* <tr>
* <td>NO_BLOCK_SUPPORT</td>
* <td>AppConfig.h</td>
* <td>Define to disable memory block read/write support in the bootloader, requiring all reads and writes to be made
* using the byte-level commands.</td>
* </tr>
* <tr>
* <td>NO_EEPROM_BYTE_SUPPORT</td>
* <td>AppConfig.h</td>
* <td>Define to disable EEPROM memory byte read/write support in the bootloader, requiring all EEPROM reads and writes
* to be made using the block-level commands.</td>
* </tr>
* <tr>
* <td>NO_FLASH_BYTE_SUPPORT</td>
* <td>AppConfig.h</td>
* <td>Define to disable FLASH memory byte read/write support in the bootloader, requiring all FLASH reads and writes
* to be made using the block-level commands.</td>
* </tr>
* <tr>
* <td>NO_LOCK_BYTE_WRITE_SUPPORT</td>
* <td>AppConfig.h</td>
* <td>Define to disable lock byte write support in the bootloader, preventing the lock bits from being set programmatically.</td>
* </tr>
* </table>
*/