http://jyhshin3.blogspot.tw/2010/01/i2c-protocol.html
1 clock = 1/22.1184 us
1 machine cycle = 12 clock = 12/22.1184 us
1 nop = 1 machine cycle = 12/22.1184 us = 542.534722 ns
100 kbit/s = 1bit per 1/100000s = 10 us
1 bit cycle = 10/0.542 = 18.432 machine cycle
2 * i2c_wait = 1 bit cycle ==> i2c_wait = 9.2 machine cycle = 9 nop
有两个疑问：
1.为什么第六步骤 2 * i2c_wait 需要乘上2?
2.再来是 i2c 需要delay 函数作用是为什么？
谢谢