1、功能说明

    该测例演示了USARTy与USARTz间通过DMA实现的基础通信。
   DMA传输TxBuffer1数据至USARTy发送数据寄存器，随后数据发送至
USARTz。USARTz接收数据，DMA从USARTz接收数据寄存器搬移数据至RxBuffer1。
比较收、发数据，比较结果存入TransferStatus变量。   


2、使用环境

    软件开发环境：KEIL MDK-ARM V5.34.
			     IAR EWARM 8.50.1 

    芯片支持：
        N32H730  
        N32H735   
        N32H735EC
        N32H760
        N32H762
        N32H765
        N32H765EC
        N32H785
        N32H785EC
        N32H787   
        

3、使用说明
	
        1、时钟源：HSI+PLL
        2、系统时钟频率：
            N32H760系列：    600MHz


    USART配置如下：
    - 波特率 = 115200 baud
    - 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
    - DMA发送模式和DMA接收模式使能
    
    USART引脚连接如下：
     - USART3_Tx.PD8 <-------> UART9_Rx.PB8
     - USART3_Rx.PD9 <-------> UART9_Tx.PB9 

    
    测试步骤与现象：
    - Demo在KEIL环境下编译后，下载至MCU
    - 复位运行,串口打印PASSED为测试通过，FAILED为测试异常。

4、注意事项


1. Function description

     This test example demonstrates basic communication between USARTy and USARTz through DMA. 
     The DMA transfers the TxBuffer1 data to the USARTy transmit data register, and then the data is sent to the 
     USARTz. USARTz receive data ，the  DMA moves the data in the UART transmit data register to the RxBuffer1. 
     Compare the received and sent data, and store the comparison result in the TransferStatus variable.


2. Development environment

    Software development environment: KEIL MDK-ARM V5.34
 			                                            IAR EWARM 8.50.1 
                                    
    Supported chips:
        N32H730  
        N32H735   
        N32H735EC
        N32H760
        N32H762
        N32H765
        N32H765EC
        N32H785
        N32H785EC
        N32H787        
        

3. How to use
    System Configuration:
        1. Clock source: HSI+PLL
        2. System Clock frequency: 
            N32H760 series:     600MHz
    
     USART is configured as follows:
     - Baud rate = 115200 baud
     - Word length = 8 data bits
     - 1 stop bit
     - checksum control disabled
     - Hardware flow control disabled (RTS and CTS signals)
     - Receiver and transmitter enable
     - DMA transmit mode enabled, DMA receive mode disabled
    
     The USART pins are connected as follows:
     - USART3_Tx.PD8 <-------> UART9_Rx.PB8
     - USART3_Rx.PD9 <-------> UART9_Tx.PB9 

    
     Test steps and phenomena:
     - Demo is compiled in KEIL environment and downloaded to MCU.
     - Reset operation, the serial port prints PASSED to indicate that the test has passed, and FAILED to indicate that the test is abnormal.


4. Attention
  