Zephyr framework add sam4 board

[chepo92]

Adds sam4e_xpro board definition for the zephyr framework, as it is officially supported

[valeros]

Hi @chepo92 ! Thanks for the PR! Have you tried to run a simple project on it? Does debugging work?

[chepo92]

Hi @chepo92 ! Do you have this board at hand? Thanks for the PR! Have you tried to run a simple project on it? Does debugging work?

I don't have exactly the devboard (ATSAM4E Xplained Pro), but one with the sam4e8e (savaged from an old 3d printer), of which now I'm wondering if has its gpios ok, as I can't toggle any pin even with atmel studio.
I'm just starting to work with and test it, I know its USB CDC is ok (atmel studio example works), but I can't get to compile zephyrs USB CDC example for this board.
I'm getting a new board anyway (same mcu) but they don't have on board debugger, so I'm also getting a J-link,
I can update later as the goal is to add support for arduino also

[chepo92]

Big update:
This PR is working with zephyr (at least a basic blink example)
Had to modify blink example for testing as my board doesn't have on board led
Example is here: https://github.com/chepo92/platform-atmelsam/tree/working-zephyr-example-sam4e

I will test jlink debug as soon as i receive the pins for soldering jtag/swd to my board,

I think this PR can be merged @valeros