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PIC24F PWM

 
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Andrew76
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PIC24F PWM
PostPosted: Wed Mar 25, 2009 3:45 pm     Reply with quote
I everyone,

I'm trying to work with PIC24F and PWM module.

What I would like to do is to control the frequency and the duty cycle of the PWM.

My code is the following:
Code:

#pin_select OC1  = PIN_B6
      
setup_timer2(TMR_INTERNAL | TMR_DIV_BY_1); 
set_compare_time(1, 0x1FFFF);
set_pwm_duty(1, 200);
setup_compare(1, COMPARE_PWM | COMPARE_TIMER2

Something works but not as I intend.
The frequency and the duty cycle still remain always the same.

I've checked PR1 register and it's always on 0xFFFF
Even changing manually, it returns to this value.

So, if I want to change frequency, I'm not able.

About the duty cycle, the register OC1R still remain at the same value and doesn't change even if programmed.
Manually same strange thing: the system doesn't change that value.

How can I do?

What's wrong with his PWM?
FvM



Joined: 27 Aug 2008
Posts: 2337
Location: Germany

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PostPosted: Wed Mar 25, 2009 5:51 pm     Reply with quote
You should be aware of possible bugs with PCD built-in functions, there have been already quite a lot. Unfortunately I didn't use PWM and only basic timer functions with PIC24 up to now
Andrew76
Guest
PostPosted: Thu Mar 26, 2009 2:10 am     Reply with quote
Thanks!!!
jordanPSI
Guest
Re: PIC24F PWM
PostPosted: Thu Aug 20, 2009 9:47 am     Reply with quote
Andrew76 wrote:


My code is the following:
Code:

#pin_select OC1  = PIN_B6
      
setup_timer2(TMR_INTERNAL | TMR_DIV_BY_1); 
set_compare_time(1, 0x1FFFF);
set_pwm_duty(1, 200);
setup_compare(1, COMPARE_PWM | COMPARE_TIMER2

Something works but not as I intend.
The frequency and the duty cycle still remain always the same.


I had the same issue with the PIC24FJ256GA106.

Try something like this:
Code:
setup_timer2(TMR_INTERNAL | TMR_DIV_BY1);
set_pwm_duty(1,200);
setup_compare(1, COMPARE_PWM_EDGE | COMPARE_TIMER2 | COMPARE_TRIG_SYNC_TIMER2);

The part I was missing was the "COMPARE_TRIG_SYNC_TIMER2".
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