Share this article, a simple analysis of the differences and trade-offs between STM32 and 51 microcontrollers.
A microcontroller, abbreviated as MCU, is essentially a device that integrates the CPU (computation and control), RAM (data storage – memory), ROM (program storage), input and output devices (serial ports, parallel ports, etc.), and an interrupt system on a single chip. In our personal computers, the CPU, RAM, ROM, and I/O are all separate chips installed on a motherboard, which forms our PC motherboard and ultimately assembles into a computer. The microcontroller simply consolidates all of these into a single chip.
51 Microcontroller
The most widely used 8-bit microcontroller is certainly the one that beginners find easiest to learn. It was first introduced by Intel, and due to its typical structure and well-managed dedicated bus registers, numerous logical bit operation functions, and a rich instruction system aimed at control, it is regarded as a “classic” that laid the foundation for the development of other microcontrollers.
Characteristics of the 51 Microcontroller
The reason the 51 microcontroller has become a classic and is easy to learn is mainly due to the following characteristics:
From internal hardware to software, there is a complete bit manipulation system known as a bit processor, where the processing object is not words or bytes but bits. It can not only process specific bits of certain special function registers within the chip, such as transferring, setting, clearing, and testing, but also perform logical operations on bits, making its functionality very complete and user-friendly.
Additionally, a dual-function address range has been specially opened in the internal RAM area, which is extremely flexible to use, providing great convenience for users.
The multiplication and division instructions also bring convenience to programming. Many 8-bit microcontrollers do not have multiplication functionality, requiring a subroutine to be programmed for multiplication, which is quite inconvenient.
Disadvantages of the 51 Microcontroller
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Functions like AD and EEPROM require expansion, increasing hardware and software burdens.
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Although the I/O pins are simple to use, they have no output capability when at high level, which is the biggest weakness of the 51 series microcontroller.
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Running speed is too slow, especially with dual data pointers; improvements could greatly facilitate programming.
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The protection capability of the 51 is poor, making it easy to damage the chip.
Application Range of the 51 Microcontroller
Currently, it is widely used in teaching environments and situations where performance requirements are not high, with the most commonly used devices being the 8051 and 80C51.
STM32 Microcontroller
The STM32 series microcontroller, introduced by ST, is well-known in the industry for its high cost-performance ratio, with no rivals. Its functionality is incredibly powerful, based on the ARM Cortex-M core designed for high-performance, low-cost, and low-power embedded applications. It features top-notch peripherals: 1μs dual 12-bit ADC, 4 Mbps UART, 18 Mbps SPI, etc. It also performs well in terms of power consumption and integration, though it is slightly less efficient compared to the MSP430, which does not diminish engineers’ enthusiasm for it.
Characteristics of the STM32 Microcontroller
The STM32 is renowned in the industry for its simple structure and easy-to-use tools combined with its powerful features, which are mainly reflected in:
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Core: ARM 32-bit Cortex-M3 CPU, maximum operating frequency of 72MHz, 1.25 DMIPS/MHz, single-cycle multiplication, and hardware division.
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Memory: On-chip integrated Flash memory ranging from 32-512KB. SRAM memory ranging from 6-64KB.
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Clock, reset, and power management: Power supply voltage of 2.0-3.6V for power and I/O interface driving voltage. POR, PDR, and programmable voltage detector (PVD). Crystal oscillators ranging from 4-16MHz. An 8MHz RC oscillation circuit calibrated before leaving the factory. An internal 40 kHz RC oscillation circuit. PLL for CPU clock. 32kHz crystal oscillator calibrated for RTC.
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Debugging mode: Serial debugging (SWD) and JTAG interface. Up to 112 fast I/O ports, up to 11 timers, and up to 13 communication interfaces.
Most Commonly Used Devices of STM32:
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STM32F103 series
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STM32 L1 series
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STM32W series
Differences Between 51 Microcontroller and STM32 Microcontroller
The 51 microcontroller is a general term for all microcontrollers compatible with the Intel 8031 instruction system. The ancestor of this series of microcontrollers is Intel’s 8031 microcontroller, which has made significant progress with the development of flash ROM technology and has become one of the most widely used 8-bit microcontrollers, with representative models such as ATMEL’s AT89 series.
The STM32 microcontroller, on the other hand, is a 32-bit series produced by ST (STMicroelectronics) using ARM’s Cortex-M3 core. Its internal resources (registers and peripheral functions) are much more abundant than those of 8051, AVR, and PIC, essentially approaching that of a computer’s CPU, making it suitable for mobile phones, routers, etc.
