通过单片机的普通IO口，模拟uart串口通信，可以工作在9600的波特率下，调试使用晶振为11.05926M-Through the MCU IO port, simulation UART serial communication, can work at 9600 baud rate, debugging using the crystal oscillator for the 11.05926M

运用单片机的4个IO口来模拟spi的功能，以此解决串口通信的问题。-Microcontroller IO port analog spi, in order to resolve the problems of serial communication.