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Delay function takes the doubel of time

Hello,
I'm using an stm32f103C8 and trying to produce a precise delay funcion.
I'm using a HSE of 72Mhz so a I supposed the clock cycle is equal to 13.8ns.
The delay function is simply a while(count--) where count has the specific number of times for looping to gain the requested time.
I made an hypothese that while(count--) takes 3 cycles to execute.
So when I need to make 1µs delay I put 24 in count.

But I found that I make 4us with count =24 that means 4 times the desired time.
Please can you help identify this problem?

Parents
  • Any assumption of the timing of HLL statements is likely to be seriously flawed
    You see the reason, why i prefer Hardware TIMERS

    Timers are designed on-chip hardware peripherals and hence very powerful. They generate precise time delays (needless to say, if configured properly).

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  • Any assumption of the timing of HLL statements is likely to be seriously flawed
    You see the reason, why i prefer Hardware TIMERS

    Timers are designed on-chip hardware peripherals and hence very powerful. They generate precise time delays (needless to say, if configured properly).

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