实现了STC的串口通信，我已经自己测试过，完全能正确接收和发送，接收采用的中断放方式。-STC implements the serial communication, I have tested their own, fully able to properly receive and send, receive interrupt used in place ways.

使用I/O口模拟两个串行口的发送与接收，验证正确-Simulate two serial ports