SAMDx1 USB DFU Bootloader Versions Save

compilation of the v1.07 code

For users that might want to cause their app to force the bootloader to run, they could write the "magic" (0xf02669ef) value to the double-tap variable location just prior to initiating a system reset. v1.06 moves this variable's location to 0x2000_0000.

this release detects a double-tap of the RESET signal to manually enter the bootloader

changed bInterfaceProtocol in USB descriptor after testing with webdfu; dfu-util wasn't bothered by the old value, but this new value is more proper and is compatible with webdfu

bootloader now computes a CRC32 over the user application and will not branch to it if this integrity check doesn't pass muster; the USB bcdDevice is now 1.02

Thanks to pid.codes, the bootloader now has a more proper USB VID:PID. Functionally, the bootloader is the same as v1.00, but the VID:PID is now 1209:2003 and the USB bcdDevice is now 1.01.

pre-compiled firmware (same for SAMD11 and SAMD21) using default PA15 for bootloader entry