STM CircleOS forum / Timebase in circleOS

FR4 · 2009-02-10 08:19:33

i need a timebase with a resolution of 1ms or less. Is there a timebase in CircleOS that i can use?

Francis · 2009-02-10 10:35:31

Nothing available immediatly (could be easily added for the next release).
Workaround: CircleOS is called by the systick irq. I believe that the default frequency for the systick is set to 1kHz (1ms).
You can make your handler called at every tick by calling: MENU_SetAppliDivider(1)
Now, your handler will be called at every second when the setting of the speed is SPEED_MEDIUM. For other frequency, you can deduct/adapt the frequency... The function RCC_GetClocksFreq of the ST libray is also usefull to know about the current clock configuration.

Francis · 2009-02-10 10:50:51

If you want your handler to be called once every ms, insert the following code in the body of your Application_Ini() function:

....
UTIL_SetPll(SPEED_MEDIUM); // Systick called once per second
MENU_SetAppliDivider(1); // Application handler called at every tick

Of course, when you call UTIL_SetPll, you have first to call UTIL_GetPll to save the previous user's settings and you have to restore it when exiting from your application. In the same way, call MENU_RestoreAppliDivider to restore the default value for AppliDivider.

# 1 2009-02-10 08:19:33 Timebase in circleOS

Timebase in circleOS

# 2 2009-02-10 10:35:31 Timebase in circleOS

Re: Timebase in circleOS

# 3 2009-02-10 10:50:51 Timebase in circleOS

Re: Timebase in circleOS

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