Arduino for STM32

A redesign has been implemented a while ago, developped by Donna.
But it was tested and it worked.
In your place I would try to drive an I2C slave module with bluepill to see whether the core works for you at all.

viewtopic.php?f=2&t=301
Which core do you intend to use?
Which pinout do you plan?
Why do you need SPI?
You can use any I2C interface.

I really don't see any point of using the "new" constructor. This will use malloc and then you do not have any overwiev how you memory is increasing / decreasing. Especially, contructing temporary objetcs in the main loop is the most common cause of memory corruption/overflow problems. Usu...

So you say PB1,4 and 5 works correctly and PA11 and 15 do not?
Strange.
It maybe has to do with the fact that PA11 was remapped if I remember correctly?
Still F103C8 generic + libmaple?
Please always mention your environment to make us easier to follow your issue.

There seems to be a problem with I2C scanner, see here: https://github.com/rogerclarkmelbourne/ ... issues/799
But the normal I2C finctions should work, it is only the scanner affected.
Have you tried to communicate with the IC?
Can you record and post here some scope plots?

It is important to set pin mode after timer init.
Then it is recommended to attach interrupt after refresh, otherwise the interrupt will be fired by refresh.
Which timer 2 pin does not work?
Timer 5 was preferred over timer 2, but you can change this by editing the mapping table.

Timerx.setPeriod() is necessary if you want to output PWM signal with a specific period, not identical with your case (maximum resolution 65535).

You should first select a board and then you will see the EEPROM examples in Arduino under File->Examples->Examples for...board.
Which board do you use?

It is not enough to set the pin mode. You have to setup the timer corresponding to the used pin (PA8 in your example is mapped to timer 1 channel 1, see here ). A usual setup looks like this: Timer1.init(); // initializes and stops the timer pinMode(PA8, PWM); // sets the pin mode Timer1.setPeriod(<...

Which core do you use?