Hi !

Thankx sougata and HenrikOlsson for your helpwhich take me into good stages

there some challenges I have any one can help me:

(1) My PIC is16cF877 have CCP1 and CCP2 can it able to generate three phase SPWM?. for my little knowledge I know that for single phase the duty cycle is stored into CCP1 to generate SPWM. for three phase should I have a pic with three CCP modules?.

(2) how can I improves these small number of steps(10) cause I read page 63/281 of PIC 16F87X data sheet and microchip application note AN655 page 1/16 I .http://ww1.microchip.com/downloads/e...tes/00655a.pdf I read the formular for bits resolution and number of steps respectively.

The maximum PWM resolution (bits) for a given PWM frequensy is given by the formular below


Resolution = log(FOSC/FWPM)/log(2) bits

I want to set my PWM frequency = 5kHZ
my FOSC = 4MHZ
which gives resolution of 10 it's ok and scale factor of 1023

but
from microchip application note AN655
PWM_Freq = (Sine_freq) • (# of steps) • 10

my sine frequency is 50Hz
PWM_Freq =5kHZ

gives me 10 steps which I think is very small to give clear SPWM .

thankx