• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 30 subscribers
  • Views 829 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS570LC4357: asm(" NOP");

mingxi liu
Intellectual 371 points
Part Number: TMS570LC4357

王工您好：

         我使用tms570LC4357芯片，时钟配置如下，我想问一下，执行一次asm(" NOP");需要化多长时间？谢谢。

       

  • 0
    TI__Guru**** 197126 points

    Hi,

    Per ARM Cortex-R5 TRM, the NOP instruction takes 1 CPU cycle.

  • 0 in reply to QJ Wang
    Intellectual 371 points

    王工：

           之前我在别的帖子里看到过是1个CPU周期，但是我就是不知道1个CPU周期怎么计算。

           您看按照我上面的时钟配置，一个cpu cycle是多久啊，谢谢。

  • +1 in reply to mingxi liu
    TI__Guru**** 197126 points

    1 CPU 周期是1个GCLK周期： 1/300 us

    You can measure the execution time by toggling a GIO pin or using PMU. To make the measurement more accurate, to execute the instruction as many time  (for example 100 times) you can between two GIO toggle actions, for example,

    Pull-high GIOA[0]

    delay

    pull-LOW GIOA[00]

    asm(" NOP");

    asm(" NOP");

    ... ... 

    asm(" NOP");

    Pull-high GIOA[0];

    From your oscilloscope, measure the duration between GIA[0] falling edge and rising edge. The execution of "NOP" is measured duration/100.