In arduino's words, arduino is a platform. His early rise and the most extensive core are based on avr single chip microcomputer. We all joked that the arduino team bought avr chips. Since you didn't ask avr, I'll just say arduino. He is easy to understand. When doing graduation, prototyping and rapid development, the hardware is easy to build, and you basically don't need to draw a board, just connect it. The code is also easy to understand. Basically, the register level is not involved. Generally speaking, it has developed rapidly. Small customization is cost-effective. Even if you really do products or research, the cost is high, and simplicity and high abstraction bring low efficiency and high resource expenditure. After the number of modules goes up, the system will not last.
Although there are arduino based on stm32, fpga, lpc, pic and other chips, the development of open source libraries and ide has not kept up, and there is no way to inherit the arduino legacy of avr. Although arduino of avr32-bit MCU is official, ARM0 and arduino yun with embedded openwrt system are also produced. But the price and convenience are simply (not to mention that most of the new chips are low-voltage io, and external modules are rarely compatible.
Before we talk about stm32, let's talk about arm. As the above person said, there are several versions of arm. Let's talk about the nearest branch. One is to use mmu memory management, which generally requires external ram for flash to work. That's how much you heard about the mobile phone processor arm, as well as the router processor and the server processor. This function is to run the system. There is also an embedded system without mmu, with ram and flash like 805 1. Now it is divided into embedded versions such as m0 m3 m4 m7, and special versions such as M0Plus upgrade. In short, it is a chip higher than 805 1 I don't know where it went. Then stm32 is a series of chips produced by st stmicroelectronics company, and bought the core (embedded) copyright from arm company, plus its own peripherals. Powerful, fast, and many peripherals. But the complexity of the register can't be compared with 805 1. Therefore, the official library has also been developed, and now a special code generation software cube has been developed to simplify the operation.
Fpga is much more powerful. These mentioned above are all single-chip computers, and the operations are step by step and logically connected in series. The Fpga is parallel, and the single chip microcomputer can only do one operation at a time. As long as fpga has enough resources (the chip is expensive), it can do hundreds of operations at the same time. Therefore, it is generally used in places that require high speed, such as video compression and high-speed network equipment. 805 1, arduino, stm32, 10 yuan can be used. Without hundreds of fpga, there will be no resources available, not even the first three. Fpga is not developed by C, you can think of it as a mathematical algorithm and then go to the circuit to execute it (video compression is one of them). More mathematics, algorithms.
To sum up, the 1 and 805 1 series are already brilliant endings. The architecture has been delayed, except for the old code and the old system upgrade, which are used in specific fields of chips. But he still occupies a large share because he is a college textbook.
Summary 2: arduino is a toy that can be played, and art students are more used for interaction. Many programmers who don't understand embedded hardware use it to make things to play with. What you really understand is either directly using the underlying avr or stm32 or something else.
To sum up, the lever of 3stm32 is worth learning. It has the highest cost performance among single-chip computers of the same nature. There are many study materials.
Summary 4 is too general, covering everything in the last summary.
Summarize 5 high. Learn your job well, and it pays well. But you have to have a doctor's degree or a master's degree to do something. If you are not here, you can't enjoy it. At the same time, the materials are few and the entry cost is high.