Fix bootloaders not starting user application if the HWB is grounded during watchdog reset.

2 files changed, 13 insertions, 18 deletions

diff --git a/Bootloaders/CDC/BootloaderCDC.c b/Bootloaders/CDC/BootloaderCDC.c
index 1f076530d..63991de75 100644
--- a/Bootloaders/CDC/BootloaderCDC.c
+++ b/Bootloaders/CDC/BootloaderCDC.c
@@ -103,8 +103,19 @@ void Application_Jump_Check(void)
 			if (!(MCUSR & (1 << EXTRF)) || (MagicBootKey == MAGIC_BOOT_KEY))
 			  JumpToApplication = true;
 
+			/* Clear reset source */
 			MCUSR &= ~(1 << EXTRF);
 		}
+		else
+		{
+			/* 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);
+		}
 	#endif
 
 	/* Don't run the user application if the reset vector is blank (no app loaded) */
diff --git a/Bootloaders/CDC/BootloaderCDC.txt b/Bootloaders/CDC/BootloaderCDC.txt
index 5f24a16e5..f8c349cde 100644
--- a/Bootloaders/CDC/BootloaderCDC.txt
+++ b/Bootloaders/CDC/BootloaderCDC.txt
@@ -64,9 +64,9 @@
  *
  *  The are two behaviours of this bootloader, depending on the device's fuses:
  *
- *  <b>If the device's BOOTRST fuse is set</b>, the bootloader will run any time the system is not reset from
+ *  <b>If the device's BOOTRST fuse is set</b>, the bootloader will run any time the system is reset from
  *  the external reset pin, unless no valid user application has been loaded. To initiate the bootloader, the
- *  device's external reset pin should be grounded.
+ *  device's external reset pin should be grounded momentarily.
  *
  *  <b>If the device's BOOTRST fuse is not set</b>, the bootloader will run only if initiated via a software
  *  jump, or if the \c HWB pin was low during the last device reset (if the \c HWBE fuse is set).
@@ -81,16 +81,6 @@
  *  Ground \c IO13 when powering the board to start the bootloader. This assumes the \c HWBE fuse is cleared and the
  *  \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
  *
- *  For board specific exceptions to the above, see below.
- *
- *  \subsection SSec_XPLAIN Atmel Xplain Board
- *  Ground the USB AVR JTAG's \c TCK pin to ground when powering on the board to start the bootloader. This assumes the
- *  \c HWBE fuse is cleared and the \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
- *
- *  \subsection SSec_Leonardo Arduino Leonardo Board
- *  Ground \c IO13 when powering the board to start the bootloader. This assumes the \c HWBE fuse is cleared and the
- *  \c BOOTRST fuse is set as the HWBE pin is not user accessible on this board.
- *
  *  \section Sec_Installation Driver Installation
  *
  *  After running this bootloader for the first time on a new computer, you will need to supply the .INF
@@ -214,12 +204,6 @@
  *  access.
  *  See <a href=https://groups.google.com/d/msg/lufa-support/CP9cy2bc8yo/kBqsOu-RBeMJ>here</a> for resolution steps.
  *
- *  \par After loading an application, it is not run automatically on startup.
- *  Some USB AVR boards ship with the BOOTRST fuse set, causing the bootloader
- *  to run automatically when the device is reset. In most cases, the BOOTRST
- *  fuse should be disabled and the HWBE fuse used instead to run the bootloader
- *  when needed.
- *
  *  \section Sec_Options Project Options
  *
  *  The following defines can be found in this demo, which can control the demo behaviour when defined, or changed in value.