1、功能说明

    此例程提供了一种DMA用法，用于在外设到RAM之间传输数据。
    

2、使用环境

    软件开发环境：KEIL MDK-ARM V5.34.0.0
    硬件开发环境： 
        N32G05x系列：
            基于评估板N32G05xRBQ7_STB V1.0开发
        N32G05x系列：
            基于评估板N32G05xRBL7_STB V1.0开发



3、使用说明
	
    1、时钟源：HSE+PLL
    2、主时钟：64MHz
    3、DMA通道：DMA_CH2，DMA_CH3，DMA_CH4，DMA_CH5
    4、SPI1 配置：
            SCK   -->  PB12
            MISO  -->  PB11
            MOSI  -->  PB10
            全双工
            主模式
            8bit传输
            极性：起始为低/第二个边沿
            软件片选
            大端在前MSB
    
    5、SPI2 配置：
            SCK   -->  PC0
            MISO  -->  PC3
            MOSI  -->  PC2
            全双工
            从模式
            8bit传输
            极性：起始为低/第二个边沿
            软件片选
            大端在前MSB
    
    6、USART1配置：
            TX  -->  PA9
            波特率：115200
            数据位：8bit
            停止位：1bit
            无校验

    7、测试步骤与现象
        a，引脚连接：PB12连接PC0，PB11连接PC3，PB10连接PC2
        b，编译下载代码复位运行
        c，从串口看打印信息，验证结果
        
4、注意事项
    1. 需根据主机时钟空闲电平来配置主机CLK引脚的上/下拉，CLKPOL为1配置为上拉，CLKPOL为0配置为下拉.


1. Function description
    This routine provides a DMA usage for transferring data between peripherals and RAM.

2. Use environment
	Software development environment: KEIL MDK-ARM V5.34.0.0
    Hardware development environment:
         N32G05x series:
            Developed based on the evaluation board N32G05xRBQ7_STB V1.0
         N32G05x series:
            Developed based on the evaluation board N32G05xRBL7_STB V1.0

3. Instructions for use
    1. Clock source: HSE+PLL
    2. Master clock: 64MHz
    3. DMA channels: DMA_CH2, DMA_CH3, DMA_CH4, DMA_CH5
4. SPI1 configuration:
        SCK   -->  PB12
        MISO  -->  PB11
        MOSI  -->  PB10
    	Full duplex
    	Main mode
    	8 bit transmission
    	Polarity: start at low/second edge
    	Piece of software to choose
    	Big end in front MSB

5. SPI2 Configuration:
        SCK   -->  PC0 
        MISO  -->  PC3
        MOSI  -->  PC2
    	Full duplex
    	From the pattern
    	8 bit transmission
    	Polarity: start at low/second edge
    	Piece of software to choose
    	Big end in front MSB

6. USART1 configuration:
        TX  -->  PA9
    	Baud rate: 115200
    	Data bit: 8 bits
    	Stop bit: 1bit
    	No check

    7. Test steps and phenomena
        A. Pin connection: PB12 connects to PC0, PB11 connects to PC3, PB10 connects to PC2
        B. Compile download code reset run
        C. View the printed information from the serial port and verify the result
        
4. Precautions
    1. The pull-up/down of the host CLK pin should be configured according to the idle level of the host clock，
        when CLKPOL is set to 1, it is configured as pull-up; when CLKPOL is set to 0, it is configured as pull-down.
