STM32 Learning-Getting Started

Two years ago, I started to contact the embedded Internet of Things, from the first 51 to the next STM8 to STM32, from WiFi to ZigBee to NB-IoT, I learned more and more complicated things, but now I look back and find myself Nothing, just take advantage of this epidemic to sum up all the bits and pieces of the past two years. The earliest to start learning STM32 is a development board for punctual atoms. Later, I also bought several other boards, but in comparison, I still feel that punctual atoms are slightly better, the data is more comprehensive, and the video explanations are also very good. If you have just started to learn STM32, you can go to the B station to watch the video of Atom Brother. Of course, it is best to buy a development board for hands-on operation. I always think that practice is the most efficient learning method.

Embedded System Overview

1. Definition of embedded system: based on application, based on computer technology, software and hardware can be customized according to requirements, so as to meet various design indicators. It differs from general-purpose computer systems in that it is designed for specific tasks.
2. Architecture: Embedded hardware ( processor , peripherals) + embedded software (operating system, application software)
3. Microcontroller and microprocessor
   • Microprocessor refers more to the part of the processor, namely the CPU
   • In addition to the processor, the microcontroller also integrates memory, timers, storage units (Flash), DMA and other peripheral interfaces, and is a computer on chip.
   • System chip: It also integrates a complete system on a single chip. A central control unit controls other subsystem modules through the bus. Generally, multiple processor cores are used.
4. Common peripheral interfaces and buses:
   • Serial communication interface: RS-232, I2C, SPI, etc.
   • USB interface
   • Multimedia card interface: SD card, CF card, etc.
   • Network interface: wired and wireless network, etc.
   • GPIO, analog-to-digital / digital-to-analog conversion (ADC / DAC) interface
5. Embedded operating system: preemptive scheduling mechanism , short response time, kernel can be tailored, and strong portability
6. Online debugging: It is realized by the hardware control module and debugging status inside the embedded processor, which needs to be realized by using an online emulator (ICE), JTAG or SWD.
7. Embedded system features:
   • It is application-oriented and has strong specificity. It needs to be tailored and configured according to application requirements.
   • Have real-time requirements, and require data acquisition, interaction and real-time response with the external environment
   • Software and hardware resources are strictly limited, and usually have requirements for miniaturization, light weight, low power consumption and low cost

---

A preliminary study of STM32

1. What is STM32
   • 32-bit MCU series based on ARM core, the core is ARM Cortex-M core (specially designed for embedded applications requiring high performance, low cost and low power consumption)
2. Cortex-M4 adopts ARMv7-ME architecture, Cortex-M0 adopts ARMv6-M architecture, Cortex-A5 / A8 adopts ARMv7-A architecture, traditional ARM7 adopts ARMv4T architecture
3. ARMv7 architecture (after 2007) defines three series with clear division of labor
   • "A" series: for cutting-edge virtual memory-based operating systems and user applications
   • "R" series: for real-time systems
   • "M" series: for microcontrollers
4. STM32F4XX：
   • Cortex-M4 core: floating-point arithmetic capabilities, enhanced DSP processing instructions
   • More storage space: up to 1M bytes of on-chip memory, up to 196K bytes of embedded SRAM, FSMC flexible external storage interface
   • Extreme operating speed: 210DMIPS processing capacity can be achieved when running at 168MHz high speed
   • More advanced peripherals: camera interface, encryption processor, USB high-speed OTG interface, FIFO DMA controller
   • Operating mode: the program and code are in Flash or RAM, and ARM acceleration is enabled
5. STM32 naming rules:
   
6. STM32 advantages:
   • Extremely high performance
   • Rich and reasonable peripherals, reasonable power consumption and reasonable price
   • Powerful software support: rich software packages
   • Comprehensive and rich technical documents
   • There are many types of chip models with wide coverage
   • Strong user base

---

如有错误，请批评指正！