The processor (or core) is the unit that executes the program of a microcontroller: it reads the instructions one by one and applies them. Its width (8, 16 or 32 bits) and its clock frequency give a first idea of its compute power (without summing up on their own the real performance, which also depends on the architecture).
Reading core names
The names met across the family overview designate processor architectures. ARM Cortex-M is a range of 32-bit cores that ARM licenses to manufacturers (STM32, Teensy, Uno R4…), graded from the frugal M0 to the powerful M7. AVR is the historic 8-bit of the first Arduino boards. Xtensa equips the ESP32 and the ESP8266, and RISC-V is a royalty-free architecture growing fast (some ESP32-C, Pico 2). A microcontroller can finally carry several cores (the ESP32 and the Pico have two) and so run two tasks in parallel.
See also
- Microcontroller — the chip that integrates the processor and its peripherals
- Memory — where the running program and the working data are held
- Firmware — the program the processor executes
- C++ — the hub of the language that program is written in
- How a program runs — how written code becomes what the processor executes