说明：  一个手册，我在网上找了很长时间才找到，而且是在国外网站上搜到的。现在很多开发板厂商，提供的DATASHEET 总有些不对。希望对别人有帮助。
(A manual, I was online looking for a very long time to find, but also in foreign countries to the site found. Now many development board vendors, providing DATASHEET there are always wrong. Want to help others.)