PIC 16f877 pwm

[sundas]

hello, i need a c code help for pwm with generating variable duty cycles from 0 t0 100%
using pic 16f877 HITECH compiler
at the moment i've generated pulse of 100%, 50% manually but i want to do it as a loop or variable duty cycles...
thanx
regards

 

[sundas]

no reply..............

 

[ayazahmed]

Dear friend i really want 2 help u but i never have worked on PWM, although i have basic concepts about it. can u tell me how u have implemented 100% and 50% duty cycle. May be then i can help u.

 

[sundas]

#include<pic.h>

void main()
{
TRISC=0x00;
CCP1CON=0x0C;
PR2=0xFF; // set PWM period for approximately 19.53KHz
CCPR1L=0xFF; // set PWM duty cycle to 50%
T2CON=0x04;
}

 

[john blue]

#include <htc.h>
#include <pic.h>

void main ()
{
int a=0xFF;
TRISC=0x00;
CCP1CON=0x0C;
PR2=0xFF; // set PWM period for approximately 19.53KHz
for(CCPR1L=0xFF,CCPR1H=0xFF;CCPR1L>0x00,CCPR1H>0x00;CCPR1L--,CCPR1H--)
_delay(100000);
T2CON=0x04;
}