如何使用USB总线接口在单片机系统中实现一个虚拟串口的原理和实现过程。在设计中，软件部分采用USB的CDC类标准来实现虚拟串口，这样可以使用操作系统（Windows,Linux）自带的驱动程序；在硬件设计中，使用自带USB从设备接口的AT89C5131单片机，提高了系统的集成度和可靠性-How to use the USB bus interface in single-chip realization of a virtual serial port system, the principle and implementation process. In the design, the software part of the adoption of USB-CDC class standards to achieve a virtual serial port, so you can use the operating system (Windows, Linux) comes with the driver　in hardware design, the use of own USB interface from the device chip AT89C5131 machine, to improve the system integration and reliability of