RS485双机通讯实验-主机，程序运行后,主机将间隔的发送0-255至从机，从机接收到后在从机的1602液晶上进行显示-Dual RS485 communication experiment- the host, the program runs, the host will send interval 0-255 to the slave, after receiving the slave to slave in 1602 on the liquid crystal display