Add support for ATSAMD21E15B

[sabas1080]

Hi @shumatech

I am trying to program an ATSAMD21E15B and I get an error, is the chip supported?

How can I help to add support?

Thanks

[sabas1080]

I had to comment on the line
https://github.com/shumatech/BOSSA/blob/master/src/Samba.cpp#L123
to work correctly

[excsniper]

Above is a quick workaround for a bug that I suspect is hanging the flashing process. BOSSA assumes a writeBufferSize of 4096B but the chip only has that much ram in total. Relevant lines

BOSSA/src/Samba.h

Line 85 in d480a1e

uint32_t writeBufferSize() { return 4096; }

BOSSA/src/Samba.h

Line 89 in d480a1e

uint32_t checksumBufferSize() { return 4096; }

If the sizes are suppose to be the same then may I also recommend refactoring them into a constant.

[Gadgeteering]

I have had the same is with a SAMR21S16 I reduce the buffer size to 2048 and it worked #110