AVR ATmega1280 单片机串口通信 串口接收字符串，四个串口同时启用，具有通信超时处理功能-AVR ATmega1280 microcontroller serial communication serial port to receive a string, four serial ports is also enabled with a communication time-out processing

51串口方式0 利用串口给数码管送数 显示零到F-51 serial mode 0 using the serial port to send the number of digital tube display zero to F