[003] embedded learning: creating project templates - using stm32cubemx

【 This paper is about Baiwen & Weidong mountain 【 IOT smart home training camp 】 Learning notes series 】

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introduction

STM32CubeMX yes ST Italian French semiconductor launched STM32 A series of chip graphic visual configuration tools , You can use the graphical wizard to Cortex-M series MCU Generate initialization code project template . It is very easy to configure... Through a step-by-step process STM32 Microcontrollers and microprocessors , As well as Arm Cortex-M Kernel or oriented Arm Cortex-A Kernel specific Linux The device tree generates the corresponding initialization C Code . 

Compare with Keil Create a project template ,STM32CubeMX Few steps 、 Quick start , The visual interface helps to understand and add interest . But the generated project template is rather bloated , And you need to write code according to the specified rules .

1 Engineering creation

1.1 Select the method to create the project

Initial operation STM32CubeMX, The following interface will pop up . Click on “ACCESS TO MCU SELECTOR”, Create a project by selecting a chip , Pictured 1 Shown .

chart 1 Create a project by selecting a chip

Then select the chip model . Enter in the search box “STM32F103C8”, Choose... On the right “LQFP48” encapsulation , Finally, click “Start Project”, Start creating projects , Pictured 2 Shown .

chart 2 Choose chip model

1.2 GPIO To configure

GPIO（General-Purpose IO ports, Universal input / Output interface ）, Used to sense external signals （ The input mode ） And control external equipment （ The output mode ）, The thin pins around the chip are GPIO.

KEY PA0;LEDPA1

chart 3 103MINI Schematic diagram of development board （ Local ）

chart 3 Weibaiwen.com 103MINI Partial schematic diagram of development board , It can be seen from the drawing that PA0 The pin is connected to the key ;PA1 Pin and LED Connected to a . According to the schematic diagram , Conduct MCU Of GPIO To configure .

Enter the pin configuration interface , This interface can graphically select chip pins and configure , Pictured 4 Shown .

chart 4 Pin configuration interface

Insert the pin PA1 Set to GPIO_Output Pattern , Insert the pin PA0 Set to GPIO_Input Pattern , After the configuration is completed, see the figure 5 Sum graph 6 Shown .

chart 5 GPIO Pin status after configuration

chart 6 GPIO Details after configuration

1.3 System clock configuration

Clock is very important for a chip , Its function is equivalent to that of human heart , People can live a healthy life only when their heart rate is normal and stable . Empathy , Only when the chip works at the legal and normal clock frequency can it ensure the normal operation of the program . STM32F103 The clock system includes internal high-speed / Low speed clock source 、 External high speed / Low speed clock source 、PLL（ PLL ） And system tick timer . So let's go through STM32CubeMX Configure the clock system , So as to deepen the understanding of the clock tree .

According to the schematic diagram , Reasonably configure the clock source . Pictured 7 Shown , First enable the external high-speed clock （HSE） And select “Crystal/Ceramic Resonator”.

chart 7 External high-speed clock （HSE） Set up

The clock source is configured as shown in the figure 8 Shown , You can see the pins PD0 and PD1 Turn green , It represents the input pin and output pin of the external crystal oscillator respectively .

chart 8 External high-speed clock （HSE） Set the pin status after completion

Next, use the external clock HSE Configure the system clock to the maximum value 72Mhz, Pictured 9 Shown .

chart 9 Source and frequency setting of system clock

In the figure 10 in , Click on “GENERATE CODE” Build project ：

chart 10 Preview the status after the clock configuration is completed

2 Engineering structure

The folder included in the new project is shown in the figure 11 Shown .

chart 11 Folder structure of the project

Each folder is described below ：

• MDK-ARM： Save the startup file
• Core： Store the main function main.c And some core files that may be modified
• Drivers： Deposit CMSIS and HAL library ;

Use Keil Open the new project , The directory tree of the project is shown in the figure 12 Shown .

chart 12 The project is in keil Directory tree structure in

3 Core code

GPIO The core code in initialization, such as code snippets 1 Shown ：

Code segment 1：GPIO initialization

The core code in the system clock configuration, such as code snippet 2 Shown ：

Code segment 2： System clock configuration

In the main function Main.c Add code snippets to 3 The code in , Download the program to 103MINI Development board . Blue by default LED Light normally on . When the user presses the key , Blue LED The light goes out , When the key is released , Blue LED Lighten up .

Code segment 3： User defined code added in the main function

Conclusion

This paper introduces the use of STM32CubeMX Create a project , To configure GPIO And the system clock .