STM32 with integrated OpAmps probably is more useful to more people (especially as your "default pick" for most electronic projects), than almost any other microcontroller.
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EDIT: Speaking of which, I'd have to imagine that most FFT algorithms for low-power / simple electronics work would rather be implemented in analog OpAmps + Analog Filters rather than digital logic (or digital filters).
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EDIT: Speaking of which, I'd have to imagine that most FFT algorithms for low-power / simple electronics work would rather be implemented in analog OpAmps + Analog Filters rather than digital logic (or digital filters).