1、功能说明
    XSPI 单线模式擦除、读、写外部Nand Flash设备

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

    系统配置
        1、时钟源：HSI+PLL
        2、系统时钟频率：
             600MHz
        3、打印：PA9 - baud rate 115200
        4、XSPI配置：
             时钟：系统时钟2分频；
             引脚：NSS0--PE5、CLK--PB2、IO0--PI9、IO1--PI10、IO2--PI11、IO3--PA6
             外部Spi_Flash设备：GD5F1GQ5

    使用方法：
        a.编译后下载程序复位运行；
        b.XSPI 初始化完成后，先通过单线SPI模式擦除Flash设备，然后读取确认数据是否为0xFF，有错误则打印报错，
           再通过单线SPI模式往 NAND Flash设备写256字节，然后读取确认数据是否为写入的内容，有错误则打印报错。

4、注意事项
       1、需要将spi_flash.c放到RAM中执行，否则flash读写执行速度太慢，会出错。
       2、需外接NandFlash。
    
1. Function description

    XSPI single-line mode erase, read, write external NAND Flash device

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: 
            600MHz
        3、Printing: PA9 - baud rate 115200
        4、XSPI Configuration:
             Clock: System clock 2 divisions;
             Pin: NSS0--PE5、CLK--PB2、IO0--PI9、IO1--PI10、IO2--PI11、IO3--PA6
             External Spi_Flash device: GD5F1GQ5

     Instructions:
        b. Compile and download the program to reset and run;
        b. After the initialization of XSPI is completed, erase the two Spi_Flash devices respectively through the standard mode, then read and confirm whether the data is 0xFF, 
            if there is any error, print an error report.
            Then Write 256 bytes to the NAND Flash device through single line SPI mode, and then read to confirm if the data is the written content. If there is an error, print an error message. and if there is any error, then print an error message.

4. Attention
    1、The spi_flash.c needs to be placed in RAM for execution, otherwise the flash read and write speed will be too slow and may cause errors.
    2、Requires an external NAND Flash.

