+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.
+ */
+uint16_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)
+{
+ bool JumpToApplication = false;
+
+ #if (BOARD == BOARD_LEONARDO)
+ /* Enable pull-up on the IO13 pin so we can use it to select the mode */
+ PORTC |= (1 << 7);
+ Delay_MS(10);
+
+ /* If IO13 is not jumpered to ground, start the user application instead */
+ JumpToApplication = ((PINC & (1 << 7)) != 0);
+
+ /* Disable pull-up after the check has completed */
+ PORTC &= ~(1 << 7);
+ #elif ((BOARD == BOARD_XPLAIN) || (BOARD == BOARD_XPLAIN_REV1))
+ /* Disable JTAG debugging */
+ JTAG_DISABLE();
+
+ /* Enable pull-up on the JTAG TCK pin so we can use it to select the mode */
+ PORTF |= (1 << 4);
+ Delay_MS(10);
+
+ /* If the TCK pin is not jumpered to ground, start the user application instead */
+ JumpToApplication = ((PINF & (1 << 4)) != 0);
+
+ /* Re-enable JTAG debugging */
+ JTAG_ENABLE();
+ #elif ((BOARD == BOARD_PROMICRO) || (BOARD == BOARD_MICRO))
+ /* Pro-Micro and Arduino Micro board use power-on reset, but no external reset. Both boards have
+ * the hardware bootloader pin HWBE enabled. Unfortunately only the external reset allows together
+ * with an enabled HWBE that the CPU start at the bootloader address independent of the FUSE_BOOTRST.
+ * That means the power-on reset will start just controlled by the FUSE_BOOTRST the bootloader or
+ * direct in the application and cannot be overridden by HWBE signal. Therfore FUSE_BOOTRST shall
+ * be enabled, otherwise the bootloader will not be reached for these boards.
+ * The bootloader checks FUSE_HWBE as *unprogammed* instead of FUSE_BOOTRST as programmed on other
+ * board variants to decide fast application start, without waiting the dedicted bootloader timeout
+ * in case of a USB, watchdog, brown-out or JTAG reset. If the watchdog reset was initiated from
+ * the bootloader marked with the MAGIC_BOOT_KEY this reset flag is reset. All other reset flags
+ * are left untouched to allow the application code checking the reset signals, especially in case
+ * of application fast start.
+ * The bootloader is entered always for external reset and power-on reset. But the bootloader is
+ * anyway exited after that dedicted timeout, if a reset-vector to the application is programmed.
+ * Once a DFU program interacts this the bootloader during this dedicted timeout, the timer stops
+ * and the application needs to be started by DFU bootloader command manually or using a reset.
+ */
+
+ /* Check if the device's forced Bootloader via Hardware Bootenable is unprogrammed */
+ if (BootloaderAPI_ReadFuse(GET_EXTENDED_FUSE_BITS) & ~FUSE_HWBE)
+ {
+ /* If the reset source was not an external or power-on reset jump to the application */
+ if (!(MCUSR & ((1 << EXTRF) || (1 << PORF))))
+ JumpToApplication = true;
+ }
+ /* If the reset source was the bootloader and the key is correct, clear it and jump to the application;
+ * this can happen in the HWBE fuse is set, and the HBE pin is low during the watchdog reset */
+ if ((MCUSR & (1 << WDRF)) && (MagicBootKey == MAGIC_BOOT_KEY))
+ {
+ JumpToApplication = true;
+
+ /* Clear reset source */
+ MCUSR &= ~(1 << WDRF);
+ }
+ #else
+ /* Check if the device's BOOTRST fuse is set */
+ if (!(BootloaderAPI_ReadFuse(GET_HIGH_FUSE_BITS) & ~FUSE_BOOTRST))
+ {
+ /* If the reset source was not an external reset or the key is correct, clear it and jump to the application */
+ if (!(MCUSR & (1 << EXTRF)) || (MagicBootKey == MAGIC_BOOT_KEY))
+ JumpToApplication = true;
projects / pub / lufa.git / blobdiff