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

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This commit is contained in:
Dean Camera
2014-10-12 16:43:30 +11:00
parent 4c637c93ba
commit a09cb7e3d8
9 changed files with 59 additions and 49 deletions
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11
Bootloaders/CDC/BootloaderCDC.c
View File

@@ -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) */

20
Bootloaders/CDC/BootloaderCDC.txt
View File

@@ -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.