nop函数实现延时

[wangyibin]

利用nop在LPC55S69实现1s延时不精准？与窗口看门狗实现的1s相比，所用时间长了?

[ZhangJennie]

Hi wangyibin 

It's not possible  to use code like nop implement precise delay time.

If precise delay is needed, please use timer. Please note, if using FRO as timer source, The FRO is +/- 2% accuracy over the entire voltage and temperature range. 

Hope this helps,

Jun Zhang