Know the microcontroller

Single chip microcomputer STM32L151CCU6

1206RGB (single)

Mobile phone crystal 3.2*2.5mm 3225 26M (26.000MHZ)

0201 package SLP0603 ESD electrostatic diode 5V one-way ESD

A single-chip microcontroller, also known as a microcontroller unit (MCU), integrates the central processing unit (CPU), memory, and input/output (I/O) interfaces into one compact chip. This integration allows for the creation of simple control systems with minimal external components, significantly reducing hardware costs. However, due to the limited space on the chip, the ROM and RAM capacities are relatively small. Despite this, modern MCUs often include essential features such as timers, interrupts, serial communication, and even analog-to-digital (ADC) and digital-to-analog (DAC) conversion capabilities.

Using a single-chip microcontroller is ideal for designing small-scale and simple control systems. These chips are widely used in everyday automation devices, smart home appliances, and consumer electronics that require intelligent control. Industrial automation systems and even children's toys also rely heavily on microcontrollers for their functionality.

There are five main types of MCUs based on their memory type:

1. **MASKROM**: The program is embedded during the manufacturing process using a mask. It’s cost-effective for mass production, like the 80C51 series.

2. **EPROM**: Erasable and reprogrammable via UV light. An example is the 87C51, which is more expensive but offers flexibility.

3. **ROMless**: These MCUs don’t have built-in ROM, requiring external memory. Examples include the 80C31, though they are less common today due to the complexity of circuit expansion.

4. **OTPROM**: One-time programmable. Once written, the program cannot be changed, making it suitable for applications where the code is final.

5. **FlashROM (MTPROM)**: Re-programmable multiple times, offering flexibility for development and testing. Popular examples include the 89C51 and 89S51, known for their low cost and ease of use.

When people refer to "8051," they are usually talking about the MCS-51 family of microcontrollers developed by Intel. This family includes various models such as 8031, 8051, 8751, 8032, 8052, and 8752. Among these, the 8051 was the first and most widely used. Other models in the series were developed by adding or modifying features from the original 8051. The term "8051" is often used generically to refer to the entire MCS-51 series.

The 8031 was particularly popular in China in the past, which is why you may still see its name in many contexts. Intel licensed the core technology of the MCS-51 to many companies, leading to the development of compatible microcontrollers by other manufacturers. One of the most well-known is the 89C51, developed by Atmel. In our upcoming experiments, we will be using the 89C51 and 89S51 to demonstrate the practical applications of microcontrollers in real-world projects.