1、功能说明
     1、SPI 主模式全双工 DMA 发送和单线接收数据
2、使用环境
     软件开发环境：KEIL MDK-ARM 5.30.0.0
     硬件环境：      基于N32G031CL-STB V1.0开发
3、使用说明
     系统配置：
         1、SystemClock：48MHz
         2、GPIO：（主模式 DEMO 板）SPI1: SCK--PA5、 MISO--PA6、MOSI--PA7
                         （从模式 DEMO 板）SPI1: SCK--PA5、 MISO--PA6、MOSI--PA7
         3、日志打印：主模式 DEMO 板 PA9(TX)，波特率：115200
     使用方法：
         1、编译后下载程序复位运行；
         2、接好串口打印工具，上电，查看打印测试成功
4、注意事项
     需要两块 demo 板配合，一块板子烧录主模式程序，一块板子烧录从模式程序，两块板子需一起上电，连接两块板子的 VCC 和 GND

1. Function description
    1. SPI master mode full duplex DMA send and single-wire receive data
2. Use environment
    Software development environment: KEIL MDK-ARM 5.30.0.0
    Hardware Environment: Developed based on N32G031CL-STB V1.0
3. Instructions for use
    System Configuration;
        1. SystemClock：48MHz
        2. GPIO：(Master mode DEMO board) SPI1: SCK--PA5, MISO--PA6, MOSI--PA7
                       (Slave mode DEMO board)    SPI1: SCK--PA5, MISO--PA6, MOSI--PA7
        3. Log print: master mode DEMO board PA9(TX), baud rate: 115200
    Instructions:
        1. After compiling, download the program to reset and run;
        2. Connect the serial port printing tool, power on, and check that the print test is successful;
4. Matters needing attention
    Two demo boards are required, one board to program the master mode program, one board to program the slave mode program, 
    the two boards need to be powered on together, and connect the VCC and GND of the two boards;