boot.c

#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/power.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <LUFA/Version.h>
#include <LUFA/Drivers/Misc/RingBuffer.h>
#include <LUFA/Drivers/USB/USB.h>
#include "bitm.h"
#include "usb.h"
#include "timer.h"
#include "boot.h"

uint32_t Boot_Key ATTR_NO_INIT;
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 (;;);
}