STM32 learning: the simplest GPIO operation steps

The ".c" library functions needed are stm32f10x_gpio.c and stm32f10x_rcc.c
 
1. Start the RCC (reset always control) of the corresponding Port x
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOx, ENABLE);
    x can be A to G, GPIO is controlled by APB2 (high-speed peripheral) clock
2. Assign values ​​to the three parameters in the GPIO initial structure (the structure name needs to be defined before the program: "GPIO_InitTypeDef GPIO_InitStructure;")
    The three parameters are
    pins: GPIO_InitStructure.GPIO_Pin=GPIO_Pin_6|GPIO_Pin_7|GPIO_Pin_8|GPIO_Pin_9|GPIO_Pin_10;
    speed: GPIO_InitStructure.GPIO_Speed=GPIO_Speed_2MHz;
    mode: GPIO_InitStructure.GPIO_Mode=GPIO_Mode_Out_PP;
    The values ​​of the three parameters can be found in the "Firmware Function Library"
3. Use the GPIO initialization function GPIO_Init(GPIOx,&GPIO_InitStructure) to define the previously assigned structure to Port x.
    x can be A to G;
4. Then you can use the GPIO_ResetBits(GPIOx,GPIO_Pin_y) function to set the pin to 0 
     or use the GPIO_SetBits(GPIOx,GPIO_Pin_y) function to set the pin to 1
     x can be: A to F;
     y can be: 0 to 15; multiple values ​​can be separated by "|", such as: GPIO_Pin_7|GPIO_Pin_8|GPIO_Pin_9
5. You can also use the GPIO_ReadInputDataBit(GPIOx,GPIO_Pin_y) function to read the value of the input pin
      or use the GPIO_ReadOutputDataBit(GPIOx,GPIO_Pin_y) function to read the value of the output pin.
      x can be: A to F;
      y can be: 0 to 15; multiple values ​​can be separated by "|", such as: GPIO_Pin_7|GPIO_Pin_8|GPIO_Pin_9
Note: a) The functions for reading the entire Port value are GPIO_ReadInputData(GPIOx) and GPIO_ReadOutputData(GPIOx)
        b) The function for writing the entire Port value is GPIO_Write(GPIOx, value)
        c) Generally, after starting according to the first 3 steps, the set GPIO pins will be set to 0 (low level)