X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/f1b6ddb7107fd9534cc6a8d6ab2d46f349d9cdb7..c7344c22ac700dacf55a8dc729111dd7781c5fed:/Bootloaders/CDC/BootloaderCDC.c diff --git a/Bootloaders/CDC/BootloaderCDC.c b/Bootloaders/CDC/BootloaderCDC.c index e9ea8ae35..ef68e148c 100644 --- a/Bootloaders/CDC/BootloaderCDC.c +++ b/Bootloaders/CDC/BootloaderCDC.c @@ -56,6 +56,34 @@ static uint32_t CurrAddress; */ static bool RunBootloader = true; +/** Magic lock for forced application start. If the HWBE fuse is programmed and BOOTRST is unprogrammed, the bootloader + * will start if the /HWB line of the AVR is held low and the system is reset. However, if the /HWB line is still held + * low when the application attempts to start via a watchdog reset, the bootloader will re-start. If set to the value + * \ref MAGIC_BOOT_KEY the special init function \ref Application_Jump_Check() will force the application to start. + */ +uint32_t MagicBootKey ATTR_NO_INIT; + + +/** Special startup routine to check if the bootloader was started via a watchdog reset, and if the magic application + * start key has been loaded into \ref MagicBootKey. If the bootloader started via the watchdog and the key is valid, + * this will force the user application to start via a software jump. + */ +void Application_Jump_Check(void) +{ + /* If the reset source was the bootloader and the key is correct, clear it and jump to the application */ + if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY)) + { + /* Turn off the watchdog */ + MCUSR &= ~(1<