diff options
Diffstat (limited to 'Bootloaders/DFU/BootloaderDFU.c')
| -rw-r--r-- | Bootloaders/DFU/BootloaderDFU.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/Bootloaders/DFU/BootloaderDFU.c b/Bootloaders/DFU/BootloaderDFU.c index 3ce2a6285..233e145ae 100644 --- a/Bootloaders/DFU/BootloaderDFU.c +++ b/Bootloaders/DFU/BootloaderDFU.c @@ -92,6 +92,27 @@ static uint16_t StartAddr = 0x0000; */ static uint16_t EndAddr = 0x0000; +/** 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)) + { + MagicBootKey = 0; + AppStartPtr(); + } +} /** Main program entry point. This routine configures the hardware required by the bootloader, then continuously * runs the bootloader processing routine until instructed to soft-exit, or hard-reset via the watchdog to start @@ -695,6 +716,9 @@ static void ProcessWriteCommand(void) { if (SentCommand.Data[1] == 0x00) // Start via watchdog { + /* Unlock the forced application start mode of the bootloader if it is restarted */ + MagicBootKey = MAGIC_BOOT_KEY; + /* Start the watchdog to reset the AVR once the communications are finalized */ wdt_enable(WDTO_250MS); } |