通过USB接口给单片机发送数据，再给DA，输出模拟信号-To the microcontroller through the USB interface to send data to give DA, the output analog signal

USB接口通讯编程指导，可用于测控，模拟，玩具，单片机等。-USB Interface programming guide, can be used for monitoring and control, simulation, toys, SCM and so on.