Delay function in ms how?

[sam239955]

Posted on November 22, 2011 at 14:14

Hi,

I need a delay(uint) function for my stm32f103ze project.

My IDE is KEIL with STM32 Std.Periph. v3.5.0

I found a snipped in a KEIL example but I don't understand it and I dont know if its correct.

volatile unsigned long TimeTick;

/*------------------------------------------------------------------------------

  Delay function

  delays number of tick Systicks (happens every 10 ms)

*------------------------------------------------------------------------------*/

void Delay (unsigned long tick)

{

    unsigned long timetick;

    timetick = TimeTick;

    while ((TimeTick - timetick) < tick);

}

Do you guys would help me please to find a solution?

with regards

alex

[emalund]

Posted on November 22, 2011 at 15:09

The answer is right there tick Systicks (happens every 10 ms)

 

 

Erik

[Tesla DeLorean]

Posted on November 22, 2011 at 17:15

You would set up a SysTick interrupt with a period that is suitable for your timing requirements. If it was ticking at 1ms, you end up with about +/-1ms of slop depending on when you enter your delay routine.

The library examples should contain a complete SysTick example, and the interrupt code is in a separate file within the project.

Another approach, which doesn't require interrupts, would be to use the Core's cycle counter, which at 72 MHz would give you about 14 nanosecond granularity.