Electronic – the significance of “microcontroller based on microprocessor”


I am aware about the basic theoretical differences between the two. Like micro controllers have ROM RAM memory etc., but microprocessor has none. But I am still confused.

  • Why is it said "A microcontroller based on microprocessor" (the very first line).

  • If ARM is a microprocessor, then why STMs use it and call it as micro controller. What's the difference?

  • Is eval board like "TI c-series launchpad" has a micro controller or a micro processor or both.

Kindly correct me if I am wrong anywhere.

Best Answer

ARM is the CPU core, which can be used to implement a microprocessor or a microcontroller.

The full sentence you referenced is:

The STM32 family of 32‑bit Flash microcontrollers based on the ARM® Cortex®‑M processor is designed to offer new degrees of freedom to MCU users.

Clearly this is largely content-free marketing babble. Don't pay much attention to it. It actually never says "microprocessor". It refers to the ARM core as a "processor", which isn't strictly right either. It's just a core, which can be used to implement various kinds of processors.

The core is more like the engine of a car. You license the design from ARM, but can heavily configure it to your needs, and putting the chassis and wheels around it is your job. You can make the result a sports car, a pickup truck, or various other types of vehicles. The marketing babble above is like saying "We've based this pickup truck on a sports car". No, they haven't. They've base the pickup truck on the same basic engine technology others have used to make a sports car with.

Again though, the important point is that this is all marketing babble. There is nothing useful to see here. Move along everyone.