[Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Andrey Nechypurenko
Hi Folks, Following my tests with PWM generation using GPIO in user space [1], I've made the RTDM module [2] to further reduce the jitter. As a result, jitter was improved, but still under heavy system load the servo motor I am trying to control starts shaking. Now, I fill stuck and hope to get

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Gilles Chanteperdrix
On 04/23/2012 01:56 PM, Andrey Nechypurenko wrote: Hi Folks, Following my tests with PWM generation using GPIO in user space [1], I've made the RTDM module [2] to further reduce the jitter. As a result, jitter was improved, but still under heavy system load the servo motor I am trying to

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Andrey Nechypurenko
retval = rtdm_task_init(pwm_task[i], // there is currently only one element in this array                       pwm-task,                       pwm_task_proc,                       0,                       RTDM_TASK_HIGHEST_PRIORITY,                       2000); // 20ms period Do not

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Gilles Chanteperdrix
On 04/23/2012 02:27 PM, Gilles Chanteperdrix wrote: On 04/23/2012 01:56 PM, Andrey Nechypurenko wrote: Hi Folks, Following my tests with PWM generation using GPIO in user space [1], I've made the RTDM module [2] to further reduce the jitter. As a result, jitter was improved, but still under

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Gilles Chanteperdrix
On 04/23/2012 02:35 PM, Andrey Nechypurenko wrote: retval = rtdm_task_init(pwm_task[i], // there is currently only one element in this array pwm-task, pwm_task_proc, 0, RTDM_TASK_HIGHEST_PRIORITY,

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Andrey Nechypurenko
retval = rtdm_task_init(pwm_task[i], // there is currently only one element in this array                       pwm-task,                       pwm_task_proc,                       0,                       RTDM_TASK_HIGHEST_PRIORITY,                       2000); // 20ms period Do not

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Gilles Chanteperdrix
On 04/23/2012 02:51 PM, Gilles Chanteperdrix wrote: On 04/23/2012 02:35 PM, Andrey Nechypurenko wrote: retval = rtdm_task_init(pwm_task[i], // there is currently only one element in this array pwm-task, pwm_task_proc, 0,

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Andrey Nechypurenko
Another trick, which this time really is a workaround is to program the timers to wake up a little bit early, and spin to wait for the exact time wanted. Sounds like the black magic exercise! :-) I would try to stay on the bright side as long as I can :-) Thanks Gilles! It is really great to

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Philippe Gerum
On 04/23/2012 02:57 PM, Andrey Nechypurenko wrote: retval = rtdm_task_init(pwm_task[i], // there is currently only one element in this array pwm-task, pwm_task_proc, 0, RTDM_TASK_HIGHEST_PRIORITY,

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Wolfgang Grandegger
On 04/23/2012 01:56 PM, Andrey Nechypurenko wrote: Hi Folks, Following my tests with PWM generation using GPIO in user space [1], I've made the RTDM module [2] to further reduce the jitter. As a result, jitter was improved, but still under heavy system load the servo motor I am trying to

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Andrey Nechypurenko
Following my tests with PWM generation using GPIO in user space [1], I've made the RTDM module [2] to further reduce the jitter. As a result, jitter was improved, but still under heavy system load the servo motor I am trying to control starts shaking. Now, I fill stuck and hope to get some

Re: [Xenomai-help] Jitter while generating PWMs with GPIO from RTDM driver

2012-04-23 Thread Wolfgang Grandegger
On 04/23/2012 03:25 PM, Andrey Nechypurenko wrote: Following my tests with PWM generation using GPIO in user space [1], I've made the RTDM module [2] to further reduce the jitter. As a result, jitter was improved, but still under heavy system load the servo motor I am trying to control starts