Generally speaking, the most commonly used 8-bit microcontrollers are three series:
1. 51 Series: With Intel MCS51 as the core, many companies have purchased its core and produced their own 51 microcontrollers, mainly including ATMEL (AT89S52, etc.), STC (such as STC89C52RC), Huabang, Motorola, and ST.
2. AVR series: represented by ATMEL's ATmega16.
3. PIC series: represented by MICROCHIP's PIC16F877.
In addition, there are specialized industrial microcontrollers that are rarely seen in daily life, such as Taiwan's Hetai, Yilong, and Samsung. These microcontrollers are often small in size, powerful in functionality, but relatively specialized and cheap in price. For example, the development equipment is expensive and most people cannot afford to use them.
The STM8 that emerged in the first two years is also very strong.
16 bit microcontrollers, particularly the MSP430 and many products from the Freescale series.
There are also quite a few 32-bit microcontrollers, but they generally include ARM cores and have begun to transition to ARM, such as STM32 and so on.