Re: [beagleboard] Set GPIO in a precisely time using usleep()

[andreas . bunte]

Thanks all for the response.
It is right, I try to generate a PWM, because all hardware PWMs are 
occupied.

I will check the PREEMPT RT kernel.

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[beagleboard] Set GPIO in a precisely time using usleep()

[andreas . bunte]

Hi,

I am trying to control a servo with my BeagleBoneBlack using Angstrom. I 
must have a high-level on a GPIO for 1 millisecond. I use the following 
simple code:

while(1){
servo.setValue(BlackLib::low);
usleep(19000);
servo.setValue(BlackLib::high);
usleep(1000);
}

The GPIO is high for about 1.5 Milliseconds. The usleep()-function is not 
linear, so it did not work with any other value e.g. usleep(500). Sometimes 
I decrease the value by one (1 microsecond) but the time decrease by 100 
microseconds.
Has anybody an idea what could be wrong? 

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