Add support for STM32F411E-DISCO board.

[otac0n]

I was looking for why this board isn't supported in PlatformIO, and came across these issues:

• mbed, SPL, arduino support for STM32F411E-DISCO platformio/platform-ststm32#51
• Add Support For Discovery F411 with the STM32F411VET6 ARMmbed/mbed-os#2390

It appears from these discussions that there is no technical reason that the board isn't available and the process to add the board is documented.

• https://os.mbed.com/platforms/ST-Discovery-F411E/
• https://os.mbed.com/teams/ST/wiki/steps-to-create-a-new-STM32-platform

I am willing to go through the process to add this, as long as my effort would not be wasted.

The concern I had is that there was an announcement that the Mbed OS is end-of-life, combined with this note on the ST wiki article above:

• The SDK code must be published on GitHub https://github.com/ARMmbed/mbed-os

which leads me to wonder if my contribution would be accepted.

[JohnK1987]

Hello and welcome!

Any contribution is welcome so I believe your effort will not be wasted. I also don't see any problem with adding this board and I believe it won't be that difficult.
I see only one potential issue for you and that is MbedCE is not supported by PlatformIO at this moment. How I remember @multiplemonomials already did some steps in this but there must be done an adapter because MbedCE and PlatformIO use different build system and that does not seem to be so easy.

BR, Jan

[JohnK1987]

@otac0n is it still relevant for you? I saw you made similar topic also on different platforms.

@multiplemonomials already did a progress #494

[otac0n]

I think I will either go with Zephyr or Arduino.

[JohnK1987]

Ok, good luck with your project.