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PWM resolution??

 
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switchblademaster
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PWM resolution??
PostPosted: Tue Jul 21, 2009 3:18 pm     Reply with quote
ok.......so I set up my timer 2 and pwm.
I am operating at an oscillator frequency of 16KHz
with a timer 2 of:
Code:

setup_timer_2(T2_DIV_BY_1,255,1);

thus my period of PWM is: 64uS which s equal to 15.625KHz

The resolution of my PWM becomes 10-bit.

My question is, if PR2=255 at maximum and I have a 10-bit resolution PWM (0-1024) which determines what value the duty cycle could be. How, could this be possible.

How does one utilize a 10-bit resolution if PR2 is only 8-bit?????

I means that every time that TMR2=PR2 the pulse goes high.......however

if TMR2 reaches value in the duty cycle register PWM goes low.

If PR2=255 and the duty cycle is a10-bit number (say 512) then PWM will never happen the output will remain high always.....

Can anybody help me??
siwtchblademaster
Guest
PostPosted: Tue Jul 21, 2009 3:20 pm     Reply with quote
ok.........i have been thinking is it that:

if i have a 10-bit resolution and say duty cycle is 512 and pr2=255 then pwm:

(512/1023)*255

is that it?????
PCM programmer



Joined: 06 Sep 2003
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PostPosted: Tue Jul 21, 2009 3:30 pm     Reply with quote
Quote:
How does one utilize a 10-bit resolution if PR2 is only 8-bit?????

If you give the set_pwmx_duty() function a parameter that is larger than
8-bits, the compiler changes the generated code so that it's using 10-bit
mode.

This thread has more information:
http://www.ccsinfo.com/forum/viewtopic.php?t=17729&start=12
switchblademaster
Guest
PostPosted: Tue Jul 21, 2009 4:12 pm     Reply with quote
ok...........I realised that.
I simulated my code and it worked that way. Thanks man.....
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