Arduino for STM32

You don't need any additional library. Virtual EEPROM is in STM32 core and it's written to work like standard Arduino EEPROM library: https://www.arduino.cc/en/Reference/EEPROM

For variables/objects bigger than 1B (8b) you need to use put()/get() methods.
write() / read() work only for 1B of data.

If you do not enable CDC or HID for USB then it will be unrecognizable because you haven't put any USB support in the program.
To fully use HID bootloader you need to enable CDC so your board will be recognized as a COM port.

Without CDC support you need to manually reset board into bootloader.

First, MCU datasheet is your friend.
There you have all information, and it clearly specifies which pins are ADC input: PA0-PA7, PB0-PB1, PC0-PC5.

Analog, doesn't mean ADC. There are analog comparators, analog outputs (DAC), OPAMPS, and probably more.

So it's working fine.
PB4 is not an ADC input on L433.

select HID for your keyboard


Ok, so that would mean using 2 USB cables wouldn't it? Or could I use dongle to do both the HID part, and the serial? I'll give that a go and see what happens :D

Yes, it means using 2 USB cables.
For now, there's no easy way of using keyboard and serial on USB ...

So, is it at all possible to edit some of the core files to make this happen? It would appear that I need to set the board to HID so that I can make use of the Keyboard.h library, so what core file to I need to edit? What do I need to look for within that file?


It is possible, but it's much ...

No. For serial communication you need CDC mode set and for keyboard you need HID. You cannot have both.
So you'll need to use UART and TTL/USB converter if you want keyboard functionality.

I have no problems with USB Serial but you need to initiate it properly (open COM port) in your program on PC, otherwise it won't work.
And in your case it looks like you haven't done it properly, otherwise you wouldn't been able to open serial monitor.
COM ports cannot be shared, so only one ...

If you need open Serial monitor at start, then program is written like this.
With USB you can check if connection is active (e.g. serial monitor opened and connected). It's often done in setup() and ppl often put there also a while loop to wait for serial monitor to connect:

while( !Serial ...

Keyboard works only on USB as it's an USB device.