1、功能说明
    1、CAN1的发送和接收参考程序。
2、使用环境
    软件开发环境：KEIL MDK-ARM V5.34
    硬件环境：
        1、基于评估板N32A455VEL7_EVB V1.0开发
        2、MCU：N32A455VEL7
3、使用说明    
    系统配置；
    /* 描述相关模块配置方法；例如:时钟，I/O等 */
        SystemClock：144MHz
        USART：TX - PA9， RX - PA10，波特率115200
        CAN1： RX - PD8， TX - PD9，波特率500K，正常模式
    /* 描述Demo的测试步骤和现象 */
        1.编译后下载程序复位运行；
        2.查看串口打印信息，CAN1每隔1S发送一帧标准帧和一帧扩展帧
          串口将MCU接收到的数据帧打印出来                
4、注意事项
    无

1. Function description
     1. The sending and receiving reference program of CAN1.
2. Use environment
     Software development environment: KEIL MDK-ARM V5.34
     Hardware environment:
         1. Developed based on the evaluation board N32A455VEL7_EVB V1.0
         2. MCU: N32A455VEL7
3. Instructions for use
     System Configuration;
     /* Describe related module configuration methods; for example: clock, I/O, etc. */
         SystemClock: 144MHz
         USART: TX - PA9, RX - PA10, baud rate 115200
         CAN1: RX - PD8, TX - PD9, baud rate 500K, normal mode
     /* Describe the test steps and phenomena of the Demo */
         1. After compiling, download the program to reset and run;
         2. View the serial port printing information, CAN1 sends a standard frame and a extended frame every 1S
           The serial port prints out the data frame received by the MCU
4. Matters needing attention
     none