Not sure the most specific definition. But in an easy to understand way, SBCs run an OS like Linux or Windows, while microcontroller boards have a single program flashed directly on to them which directly interacts with the hardware.
Microcontrollers are super cheap and have incredibly low latency so they are great for when you need to do something like pulse an output pin with sub millisecond accuracy, but have very very little compute compared to a real CPU and can’t run normal software.
Microcontrollers are super cheap and have incredibly low latency so they are great for when you need to do something like pulse an output pin with sub millisecond accuracy, but have very very little compute compared to a real CPU and can’t run normal software.