程序验证实现，P2口四位控制RS485命令发送格式，P1口有高电平时，接P3.0口的灯一直闪烁，否则不亮，同时发送给电脑显示P1口的状态-Program verification to achieve P2 port four control RS485 command transmission formats, P1 port high, then P3.0 port light has been flashing, and otherwise does not shine, at the s