Question on PIC PWM resolution

[eblc1388]

I can't understand how the 5.5 bit resolution result in the image is calculated.

For PR2=0x17, that's 10111 in binary. Adding the two bits in CCP1CON to the right results in 1011111, which is the max possible value for duty cycle.

Therefore the possible value of duty cycle ranges from 0 to 1011111. But why is this 5.5 bit resolution?

 

[Papabravo]

Would 6.5 make you happier?

The expression should be log_base_2(96) = 6.58
96 is the number of possible values you get in the range [00.5F]

 

[eblc1388]

Would 6.5 make you happier?

The expression should be log_base_2(96) = 6.58
96 is the number of possible values you get in the range [00.5F]

Thanks for the clarification.

This "5.5 bit resolution" information appeared in Microchip datasheets and both the 16F and 18F Reference Manuals spanning several years(1997~2001) so I thought I better ask.

 

[Papabravo]

It's a good catch! Bravo