> This is a project whose main focus is electronics, building an oscilloscope that can serve as a simple study tool.
> The "front-end" for signal processing is already ready. The chip programming is missing.
Choosing a general-purpose MCU like a Cortex M4 for this purpose means relatively moderate specs / requirements.
> Programming in STM is part of the learning process.
> I don't have much experience with STM.
Not the best starting conditions, I would say.
A result with acceptable performance require some advanced understanding, hours of studying reference manuals & datasheets, and some experience.
> The chip has two ADCs, the F411 only has one, and I believe that the F303 is the best for this case, even though it's obsolete.
Is the F303 obsolete ? I think not.
You don't need two ADCs, just two or more channels of one ADC.
The small gain in sample frequency from using interleaved dual/triple mode ist most probably not worth the extra effort.
> As you can see from the code, the ADC, SPI, DMA, etc. handling is separate.
There is a bit more involved here.
For proper performance you need to link the ADC with DMA, to unload the core. And most probably link it to a timer as sample time base.
This requires some planning and reference manual consultation, especially if you need flexible sample rates and buffer sizes.
In addition, the F303 is quite limited in RAM and Flash size. And not all RAM is accessible by DMA.
