Support for the STMF723 Disco Board

[pschatzmann]

Pull Request

Summary

I have a STMF723 Disco Board (with a STM32F723IEK6 mcu) which was missing as supported board. Therefore I added support to the ARDUINO_DISCO_F723IE

Validation

The tests can be found in this repository:

• Blink Sketch: passed
• Button Test: passed
• Testing the Screen: passed
• Testing Serial Output w/o USB: passed
• Testing Serial Output with USB: passed

[fpistm]

Thanks for the PR. LGTM.
Maybe 2 questions:

• Why not use the HSE for the clock config ?
• Add a custom peripheral pins to save memory and avoid reserved pin usage ?

[pschatzmann]

This was my first board, so I was not sure to what to pay attention to:

• I agree with you, since the board has an external clock, we should use it!
• I was not really sure what you meant with custom peripheral pins: so I alligned the setup with what has been done for the STM32F746NG as baseline and you were right, it saved about 4000 bytes-

The requested changes have been committed!