USB 转串口是淘宝买的
http://item.taobao.com/item.htm?spm=a1z09.2.9.50.YOJBwG&id=38963495468&_u=4m1drce4153
驱动下载
选 macos
http://www.silabs.com/products/mcu/pages/usbtouartbridgevcpdrivers.aspx
安装后重启
打开 terminal输入
screen /dev/cu.SLAB_USBtoUART 115200
连接好线 R--->T T--->R
最后连接电源
ok