1、功能说明

    该演示显示了USART模块LIN模式作为主节点轮询发送主请求帧（0x3C）和从应答帧（0x3D）。

2、使用环境

    软件开发环境：EIL MDK-ARM V5.34.0.0
                          IAR EWARM 8.50.1
    硬件环境：N32G430C8L7-STB V1.0


3、使用说明

    系统时钟配置如下：
    - 时钟源 = HSE + PLL
    - 系统时钟 = 128MHz
    
    USART配置如下：
    - 波特率 = 9600baud
    - 字长 = 8数据位
    - 1停止位
    - 校验控制禁用
    - 硬件流控制禁用（RTS和CTS信号）
    - 接收器和发送器使能
    
    USART引脚连接如下：    
    - USART1_ Tx.PA9
    - USART1_ Rx.PA10
    
    - LIN mode master         LIN mode slave
    - USART2_Tx.PA6  <-->  USART2_Rx.PA7  
    - USART2_Rx.PA7  <-->  USART2_Tx.PA6  

    
    测试步骤与现象：
    a、 跳线连接到主机的从属引脚
    b、 一个开发板编译并下载LIN_Master代码作为主代码
         另一个开发板编译并下载LIN_Slave代码作为从属代码
    c、 重置从设备，然后重置主设备
   d、 主轮询发送请求帧（0x3C）和应答帧（0x3D）
         发送请求帧（0x3C）：主设备向从设备发送一个8字节的0x0F，并打印相关信息
         发送应答帧（0x3D）：从机收到应答帧后，向主机回复8字节0x01消息，并且主控打印相关信息


4、注意事项




1. Function description

    This demo shows that the USART module LIN mode as the slave node polling to receive the master
     request frame (0x3C) and the slave reply frame (0x3D).


2. Use environment
    Software development environment: KEIL MDK-ARM V5.34.0.0
    Hardware environment: Developed based on the evaluation board N32G430C8L7-STB V1.0



3. Instructions for use
     The system clock configuration is as follows:
     - Clock Source = HSI + PLL
     - System Clock = 128MHz
    
     USART is configured as follows:
     - Baud rate = 9600baud
     - Word length = 8 data bits
     - 1 stop bit
     - Parity control disabled
     - Hardware flow control disabled (RTS and CTS signals)
     - Receiver and transmitter enable
     -LIN mode enable

    Print pin connection is as follows:
    - USART1_ Tx.PA9
    - USART1_ Rx.PA10
   
    - LIN mode master         LIN mode slave
    - USART2_Tx.PA6  <-->  USART2_Rx.PA7 
    - USART2_Rx.PA7  <-->  USART2_Tx.PA6  
    
    Test steps and phenomena:
    a, the jumper connects to the slave pin of the master
    b, one development board compiles and downloads LIN_Master code as the master and 
        the other development board compiles and downloads LIN_Slave code as the slave
    c. Reset the slave and then the master
    d, master polling sends request frame (0x3C) and reply frame (0x3D)
       Receiving a request frame (0x3C) : The slave prints an 8-byte 0x0F message
       Receiving a reply frame (0x3D) : The slave replies an 8-byte 0x01 to the master


4. Attention
    none