diff options
Diffstat (limited to 'Bootloaders/CDC/BootloaderCDC.txt')
-rw-r--r-- | Bootloaders/CDC/BootloaderCDC.txt | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/Bootloaders/CDC/BootloaderCDC.txt b/Bootloaders/CDC/BootloaderCDC.txt index 55e5e55a4..5f24a16e5 100644 --- a/Bootloaders/CDC/BootloaderCDC.txt +++ b/Bootloaders/CDC/BootloaderCDC.txt @@ -59,9 +59,27 @@ * * \section Sec_Running Running the Bootloader * - * This bootloader is designed to be started via the HWB mechanism of the USB AVRs; ground the HWB pin (see device - * datasheet) then momentarily ground /RESET to start the bootloader. This assumes the HWBE fuse is set and the BOOTRST - * fuse is cleared. + * On the USB AVR8 devices, setting the \c HWBE device fuse will cause the bootloader to run if the \c HWB pin of + * the AVR is grounded when the device is reset. + * + * 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 + * 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. + * + * <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). + * + * 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. * * For board specific exceptions to the above, see below. * |