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2022/2/14, The second training of basic class .

The main content is ： The structure of single chip microcomputer 、 The development mode of single chip microcomputer and STM32CubeMX Project creation .

1、 How to find information after getting a chip ： for example STM32F103C8T6 You can search directly on Baidu or on ST Search on the official website Home - STMicroelectronics.​​​​​​

2、 The smallest system of single chip microcomputer ： Power part 、 Crystal oscillator part 、 Reset part .

（1）、 Power part ： The single chip microcomputer can work only when it is powered , Access to information ,103C8T6 Need to improve 2V-3.6V The power supply , By looking up MINI The schematic diagram of the development board , You can know MINI The power supply of the development board is USB The plug 、TVS tube 、0.5A Quickly restore the fuse 、 Linear regulator and capacitor .

（2）、 Crystal oscillator part ： In some external circuits , It can produce sine wave with stable frequency and peak value . Now SCM basically has internal crystal oscillator , Compared with the external crystal oscillator , The internal crystal oscillator error will be a little larger , Generally in 3% about , But this internal crystal oscillator can meet most of the needs , Adding an external crystal oscillator is generally to reduce the system clock error or make the MCU reach a higher dominant frequency . Check the schematic diagram to see MINI Crystal oscillator circuit of development board ,8MHZ Crystal oscillator and 2 star 22PF Capacitance composition of .

（3）、 Reset part ： The MCU needs to be reset once when it is powered on , therefore , Reset circuit is also a part of the smallest system of single chip microcomputer . SCM usually has a low voltage reset pin , That is, when input to low level , Single chip reset . Check the schematic diagram to see MINI The reset part of the development board is controlled by the touch switch 、 resistance 、 The capacitance consists of . When the resistor charges the capacitor , The voltage of the capacitor rises slowly to VCC. When chip The reset foot is close to the low level , Chip reset is close VCC, Therefore, the chip stops resetting and completes resetting .

2、 The development mode of single chip microcomputer ： Use assembly operation register 、 Use c Language operation registers 、 Use the library to develop .

Use assembly operation register ： High execution efficiency , It is difficult to write 、 Poor portability .

Use C Language operation registers ： Moderate execution efficiency , Low writing efficiency 、 Poor portability .

Use the library to develop ： Standard library 　 Less efficient execution , Efficient writing 、 The portability is slightly lower .HAL library 　 Inefficient execution 、 Efficient writing 、 Good portability .

３、STM32CubeMX Project creation ：

 

  After the above operations, you can control LED flashing .