iic 之24C256存储器 及PCF8563

参考文章:

http://www.21ic.com/jichuzhishi/mcu/memory/2013-02-28/159439.html 

完整的例子:

http://blog.csdn.net/u013053268/article/details/52399301

关于iic 与 spi总线

http://blog.csdn.net/skyflying2012/article/details/11910173