about setup_timer_2.. please help

huiching · Joined: 25 Mar 2011 Posts: 3

I have a gear motor.. rpm: 50
What parameter i should put in setup_timer_2()
For example setup_timer_2(T2_DIV_BY_4, 255, 1);
How to make the calculation?
Kindly please help me..

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

1. What interrupt rate do you want from Timer2 ? 50 rpm is 3000 Hz.
Do you want a 3 KHz interrupt rate ?

2. Or do you even want interrupts ? Do you actually want to run PWM ?

3. Also, what is the oscillator frequency of your PIC ?

To get help on this forum, you need to post information about your
project.

---------------
In case your question is about PWM, here are the links to previous threads:

PWM frequency formula:
http://www.ccsinfo.com/forum/viewtopic.php?t=17993

Duty cycle formula:
http://www.ccsinfo.com/forum/viewtopic.php?t=42417&start=1

PWM postscaler explanation:
http://www.ccsinfo.com/forum/viewtopic.php?t=29786&start=1
Sample code for PWM postscaler:
http://www.ccsinfo.com/forum/viewtopic.php?t=41473&start=3

Link to a PWM calculator program:
http://www.ccsinfo.com/forum/viewtopic.php?t=40450

huiching · Joined: 25 Mar 2011 Posts: 3

cycle time has an equation of (1/clock)*4*t2div*(period+1).
in my program, clock = 20 MHz and period equal 255
so, cycle time = 1/20M) * 4 * 4 * 256

Is the above statement true?

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You still didn't say what you're using Timer2 for.
Is it for Timer2 interrupts, or is it for hardware PWM ?
So, I can't help you.