基于ARM Cortex-M4F(TM4C123)单片机 【USB应用实验】
编程控制TM4C123微控制器的USB 模块，与PC机交互数据
【功能】
（1）PC机从命令行CMD 窗口发送指令，可以控制高亮LED灯的亮度（PWM模式调光）；
（2）PC机从命令行CMD 窗口发送指令，可以控制SPI接口DAC7512输出正弦波的峰峰值和频率，控制格式自定；
（3）从PC机CMD窗口输入的字符串（回车结尾，EXIT退出）显示在12864液晶屏上来自MCU端的事件显示在PC机CMD窗口，可使用不同颜色标记不同事件
　（4）可从PC机发送文本文件到MCU；来自MCU的字符串显示在窗口中(Based on ARM Cortex-M4F (TM4C123) single chip microcomputer [USB application experiment]
Program control TM4C123 microcontroller USB module, interact with PC data.
[function]
(1) PC sends commands from the command line CMD window to control the brightness of high brightness LED lights (PWM mode dimming).
(2) the PC sends commands from the command line CMD window to control the peak and frequency of the SPI interface DAC7512 output sine wave, and the control format is self determined.
(3)The string entered from the PC CMD window (carriage return, EXIT exit) is displayed on the 12864 LCD screen.
Events from the MCU side are displayed in the PC CMD window, and different colors can be used to mark different events.
(4) Text files can be sent from PC to MCU; strings from MCU are displayed in windows.)