English version:

SDK Development Guide @ http://bbs.espressif.com/viewtopic.php?f=51&t=1024
AT Commands User Guide @ http://bbs.espressif.com/viewtopic.php?f=51&t=1022
All documentations @ http://bbs.espressif.com/viewforum.php?f=51

中文文档：

SDK 编程手册 @ http://bbs.espressif.com/viewtopic.php?f=51&t=1024
AT 指令集 @ http://bbs.espressif.com/viewtopic.php?f=51&t=1022
全部开发文档 @ http://bbs.espressif.com/viewforum.php?f=51