3 * This file contains special DoxyGen information for the generation of the main page and other special
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4 * documentation pages. It is not a project source file.
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8 * \page Page_SoftwareBootloaderStart Entering the Bootloader via Software
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10 * A common requirement of many applications is the ability to jump to the programmed bootloader of a chip
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11 * on demand, via the code's firmware (i.e. not as a result of any physical user interaction with the
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12 * hardware). This might be required because the device does not have any physical user input, or simply
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13 * just to streamline the device upgrade process on the host PC.
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15 * The following C code snippets may be used to enter the bootloader upon request by the user application.
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16 * By using the watchdog to physically reset the controller, it is ensured that all system hardware is
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17 * completely reset to their defaults before the bootloader is run. This is important; since bootloaders
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18 * are written to occupy a very limited space, they usually make assumptions about the register states based
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19 * on the default values after a hard-reset of the chip.
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21 * \section Sec_SoftareBootAVR8 AVR8 Architecture
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22 * The following software bootloader jump code is written for the AVR8 architecture.
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25 * #include <avr/wdt.h>
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26 * #include <avr/io.h>
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27 * #include <util/delay.h>
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29 * #include <LUFA/Common/Common.h>
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30 * #include <LUFA/Drivers/USB/USB.h>
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32 * uint32_t Boot_Key ATTR_NO_INIT;
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34 * #define MAGIC_BOOT_KEY 0xDC42ACCA
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35 * #define BOOTLOADER_START_ADDRESS (FLASH_SIZE_BYTES - BOOTLOADER_SEC_SIZE_BYTES)
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37 * void Bootloader_Jump_Check(void) ATTR_INIT_SECTION(3);
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38 * void Bootloader_Jump_Check(void)
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40 * // If the reset source was the bootloader and the key is correct, clear it and jump to the bootloader
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41 * if ((MCUSR & (1 << WDRF)) && (Boot_Key == MAGIC_BOOT_KEY))
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44 * ((void (*)(void))BOOTLOADER_START_ADDRESS)();
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48 * void Jump_To_Bootloader(void)
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50 * // If USB is used, detach from the bus and reset it
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53 * // Disable all interrupts
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56 * // Wait two seconds for the USB detachment to register on the host
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59 * // Set the bootloader key to the magic value and force a reset
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60 * Boot_Key = MAGIC_BOOT_KEY;
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61 * wdt_enable(WDTO_250MS);
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66 * Note that the bootloader magic key can be any arbitrary value. The <em>FLASH_SIZE_BYTES</em> and
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67 * <em>BOOTLOADER_SEC_SIZE_BYTES</em> tokens should be replaced with the total flash size of the AVR
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68 * in bytes, and the allocated size of the bootloader section for the target AVR.
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