1、功能说明
    1、TIM3 CH2上升沿计算频率
2、使用环境
    软件开发环境：  KEIL MDK-ARM V5.34.0.0
    硬件环境：      基于N32G031C8L7-STB V1.0开发
3、使用说明
    系统配置:
        1、时钟源：
                    HSE=8M,PLL=48M,AHB=48M,APB1=48M,APB2=48M,TIM3 CLK=48M
        2、中断：
                    TIM3 CH2上升沿中断打开，优先级1
        3、端口配置：
                    PA7选择为TIM3 CH2输入
                    PA3选择为IO 输出
        4、TIM：
                    TIM3 CH2 上升沿捕获中断打开
    使用方法：
        1、编译后打开调试模式，连接PA3与PA7，将变量TIM3Freq、gOnePulsEn添加到watch窗口
        2、默认gOnePulsEn=0，每次手动给gOnePulsEn=1，此时可以看到TIM3Freq计算出来的频率值
4、注意事项
    无

1. Function description
    1. TIM3 CH2 rising edge calculation frequency
2. Use environment
    Software development environment: KEIL MDK-ARM V5.34.0.0
    Hardware environment: Developed based on the evaluation board N32G031C8L7-STB V1.0
3. Instructions for use
    System configuration:
        1. Clock source:
            HSE=8M, PLL=48M, AHB=48M, APB1=48M, APB2=48M, TIM3 CLK=48M
        2. Interruption:
            TIM3 CH2 rising edge interrupt open, priority 1
        3. Port configuration:
                     PA7 is selected as TIM3 CH2 input
                     PA3 is selected as IO output
        4. TIM:
            TIM3 CH2 rising edge capture interrupt is opened
Usage method:
    1. Open debugging mode after compilation, connect PA3 to PA7, add variables TIM3Freq, gOnePulsEn to the watch window
    2. Default gOnePulsEn=0, each time you manually give gOnePulsEn=1, you can see the frequency value calculated by TIM3Freq
4. Matters needing attention
    None