During live broadcasts, many students ask about the differences between the 51 microcontroller and the STM32 microcontroller, or which microcontroller is more powerful. Let’s look at this from several specific aspects.
1. Core Performance:
The 51 microcontroller: is generally an 8-bit microcontroller. You can understand it as being able to process 8 bits of data at a time. The clock speed is also relatively slow, commonly ranging from 12MHz to 24MHz, and now the AI8051U can reach 40MHz, with the speed of 51 microcontrollers increasing over time.
The STM32 microcontroller: is a 32-bit microcontroller. It can process 32 bits at a time. The clock speed is very high, easily reaching 72MHz, several hundred MHz, or even higher.
2. Resource Size:
The internal resources of a microcontroller are mainly related to the core, and different models have different resources, which need to be checked in the data sheet. Therefore, the size of resources cannot be compared casually; specific microcontroller models must be compared.
The 51 microcontroller: has rich resources.
Program storage space Flash: generally ranges from several KB to tens of KB.
RAM: only a few hundred bytes, such as 256 bytes, 512 bytes, etc. The larger AI8051U has 34K SRAM.
Peripherals: include traditional configurations of microcontrollers, such as UART (serial port), I2C, SPI, timers, CAN, LIN, etc.
The STM32 microcontroller: has abundant resources.
Program storage space Flash: ranges from tens of KB to over MB.
RAM: ranges from tens of KB to several hundred KB.
In addition to basic peripherals, it also integrates advanced peripherals such as USB, Ethernet, CAN bus, DMA, encryption modules, SDIO interfaces, etc.
3. Development Method:
The 51 microcontroller is often developed by directly manipulating registers. For example, if you want to set the P1.0 pin to output low, you might write P1 = 0xFE;. This method is very direct and close to the hardware level, but it can be cumbersome when configuring complex functions. Advanced 51 microcontrollers can also run RTOS: uC/OS-II, FreeRTOS.
The STM32 microcontroller is mainly developed using library functions. ST provides standard libraries and HAL libraries, which encapsulate the complex steps of manipulating registers into functions. If you want to make an LED blink, you don’t need to manipulate registers directly; instead, you call a function like HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_0); to achieve this.
Learning 51 can give you a deep understanding of how microcontrollers work at the lowest level. Using STM32, you need to learn to use the official library functions and focus more on the product’s functionality itself.
4. Cost and Application Scenarios:
The 51 microcontroller has a high cost-performance ratio. It is an irreplaceable choice for cost-sensitive products with fixed functions, such as remote controls, toys, small appliances, etc. With the updates of STC, many chips are also becoming more advanced, and the official has open-sourced the software and hardware design files for the STC32 quadcopter.
The STM32 microcontroller: prices range from a few dollars to several tens of dollars. It is used in products that require high performance, complex functions, and need to connect to networks or complex interfaces, such as smart home devices, IoT modules, drone flight controllers, industrial controllers, medical devices, etc.
You can start with 51, then learn STM32. The 51 is the best choice for building a solid hardware foundation and understanding the working principles of microcontrollers. Once you understand the low-level workings of 51, learning STM32 and its library functions will be clearer, and your understanding will be deeper.
No one is better; only who is more suitable. When making products, choose based on functional requirements, cost budget, and development cycle. Use 51 to solve problems that can be addressed without using STM32, which is called cost control. For tasks that 51 cannot complete, decisively choose STM32, which is called technical selection.
From 51 to STM32, you need to complete the shift from hands-on involvement to effective tool usage. Learning to read data sheets, consult library function manuals, and use tools like STM32CubeMX is key to mastering STM32.