从PC的总线到ARM内部总线
http://wdqfirst.blog.163.com/blog/static/11334741120095882014967/
http://blogold.chinaunix.net/u3/99873/showart_2000262.html
https://files.cnblogs.com/arci/Introduction_to_AMBA_Bus_System.pdf
PC架构系列：CPU/RAM/IO总线的发展历史！
http://blog.csdn.net/xport/archive/2006/11/16/1387928.aspx