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PIC Code - PWM (50% Duty Cycle)

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devonsc

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Hi there,

I'm a newbie in using PIC microcontroller and would like to ask something regarding the duty cycle of a PWM coding.

If its not too much trouble, can anyone briefly explain how do I determine the duty cycle of a PWM duty cycle in the coding? Is it true that 255 (decimal) is equivalent to 100% duty cycle while 0 (decimal) is equivalent to 0% duty cycle? If this is right, does it mean that I should write:

movlw d'127'

for a duty cycle of 50%? Advice needed..Please? Thanks in advance..
 

Your guess is correct: for 50% the number is 127d.
 

Thanks a lot.

By the way, I'm using PIC 16F876.
 

The PIC16f876 has 2 PWM modules with a resolution of 10bits. So your period could have a count of 1024. The data sheet gives formulas for calculating the duty cycle based on the frequency and resolution.
 

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