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qmk_firmware/Bootloaders/Printer/BootloaderPrinter.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 Printer 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>Printer Class</td>
* </tr>
* <tr>
* <td><b>USB Subclass:</b></td>
* <td>Printer Subclass</td>
* </tr>
* <tr>
* <td><b>Relevant Standards:</b></td>
* <td>USBIF Printer 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 Generic Text Only Printer device, capable of reading and parsing
* "printed" plain-text Intel HEX files 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.
*
* \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
*
* This bootloader uses the Generic Text-Only printer drivers inbuilt into all modern operating systems, thus no
* additional drivers need to be supplied for correct operation.
*
* \section Sec_HostApp Host Controller Application
*
* This bootloader is compatible with Notepad under Windows, and the command line \c lpr utility under Linux.
*
* \subsection SSec_Notepad Notepad (Windows)
*
* While most text applications under Windows will be compatible with the bootloader, the inbuilt Notepad utility
* is recommended as it will introduce minimal formatting changes to the output stream. To program with Notepad,
* open the target HEX file and print it to the Generic Text Only printer device the bootloader creates.
*
* \subsection SSec_LPR LPR (Linux)
*
* While the CUPS framework under Linux will enumerate the bootloader as a Generic Text-Only printer, many
* applications will refuse to print to the device due to the lack of rich formatting options available. As a result,
* under Linux HEX files must be printed via the low level \c lpr utility instead.
*
* \code
* cat Mouse.hex | lpr
* \endcode
*
* \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_PRINTER_SIGNATURE 0xDF20
*
* #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_PRINTER_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, new firmware fails to be sent to the device via CUPS.
* Only a limited subset of normal printer functionality is exposed via the
* bootloader, causing CUPS to reject print requests from applications that
* are unable to handle true plain-text printing. For best results, the low
* level \c lpr command should be used to print new firmware to the bootloader.
*
* \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>
* <td>
* None
* </td>
* </tr>
* </table>
*/
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