mirror of
https://github.com/qmk/qmk_firmware.git
synced 2024-12-22 17:39:55 +00:00
72 lines
2.7 KiB
Plaintext
72 lines
2.7 KiB
Plaintext
|
/** \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.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/**
|
||
|
|
* \page Page_SoftwareBootloaderStart Entering the Bootloader via Software
|
||
|
|
*
|
||
|
|
* A common requirement of many applications is the ability to jump to the programmed bootloader of a chip
|
||
|
|
* on demand, via the code's firmware (i.e. not as a result of any physical user interaction with the
|
||
|
|
* hardware). This might be required because the device does not have any physical user input, or simply
|
||
|
|
* just to streamline the device upgrade process on the host PC.
|
||
|
|
*
|
||
|
|
* The following C code snippets may be used to enter the bootloader upon request by the user application.
|
||
|
|
* By using the watchdog to physically reset the controller, it is ensured that all system hardware is
|
||
|
|
* completely reset to their defaults before the bootloader is run. This is important; since bootloaders
|
||
|
|
* are written to occupy a very limited space, they usually make assumptions about the register states based
|
||
|
|
* on the default values after a hard-reset of the chip.
|
||
|
|
*
|
||
|
|
* \section Sec_SoftareBootAVR8 AVR8 Architecture
|
||
|
|
* The following software bootloader jump code is written for the AVR8 architecture.
|
||
|
|
*
|
||
|
|
* \code
|
||
|
|
* #include <avr/wdt.h>
|
||
|
|
* #include <avr/io.h>
|
||
|
|
* #include <util/delay.h>
|
||
|
|
*
|
||
|
|
* #include <LUFA/Common/Common.h>
|
||
|
|
* #include <LUFA/Drivers/USB/USB.h>
|
||
|
|
*
|
||
|
|
* uint32_t Boot_Key ATTR_NO_INIT;
|
||
|
|
*
|
||
|
|
* #define MAGIC_BOOT_KEY 0xBADCAFE5
|
||
|
|
* #define BOOTLOADER_START_ADDRESS ((FLASH_SIZE_BYTES - BOOTLOADER_SEC_SIZE_BYTES) >> 1)
|
||
|
|
*
|
||
|
|
* void Bootloader_Jump_Check(void) ATTR_INIT_SECTION(3);
|
||
|
|
* void Bootloader_Jump_Check(void)
|
||
|
|
* {
|
||
|
|
* // If the reset source was the bootloader and the key is correct, clear it and jump to the bootloader
|
||
|
|
* if ((MCUSR & (1 << WDRF)) && (Boot_Key == MAGIC_BOOT_KEY))
|
||
|
|
* {
|
||
|
|
* Boot_Key = 0;
|
||
|
|
* ((void (*)(void))BOOTLOADER_START_ADDRESS)();
|
||
|
|
* }
|
||
|
|
* }
|
||
|
|
*
|
||
|
|
* void Jump_To_Bootloader(void)
|
||
|
|
* {
|
||
|
|
* // If USB is used, detach from the bus and reset it
|
||
|
|
* USB_Disable();
|
||
|
|
*
|
||
|
|
* // Disable all interrupts
|
||
|
|
* cli();
|
||
|
|
*
|
||
|
|
* // Wait two seconds for the USB detachment to register on the host
|
||
|
|
* Delay_MS(2000);
|
||
|
|
*
|
||
|
|
* // Set the bootloader key to the magic value and force a reset
|
||
|
|
* Boot_Key = MAGIC_BOOT_KEY;
|
||
|
|
* wdt_enable(WDTO_250MS);
|
||
|
|
* for (;;);
|
||
|
|
* }
|
||
|
|
* \endcode
|
||
|
|
*
|
||
|
|
* Note that the bootloader magic key can be any arbitrary value. The <em>FLASH_SIZE_BYTES</em> and
|
||
|
|
* <em>BOOTLOADER_SEC_SIZE_BYTES</em> tokens should be replaced with the total flash size of the AVR
|
||
|
|
* in bytes, and the allocated size of the bootloader section for the target AVR.
|
||
|
|
*
|
||
|
|
*/
|
||
|
|
|