Need help for pwm

[ahmad]

I write the following program to generate pwm and there is no output 0n rc2/ccp1 pin ,any body help me.

#include <16F877A.h>
#fuses HS
#fuses NOWDT
#fuses NOPROTECT
#fuses NOLVP
#fuses NODEBUG
#fuses NOPUT
#fuses NOBROWNOUT
#use delay(clock=20000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)
#use fast_io(A)
#use fast_io(B)
#use fast_io(C)
#use fast_io(D)
#pragma zero_ram
#define motora PIN_B7
void main(void)
{

set_tris_c(0b00000000);

setup_timer_2(T2_DIV_BY_16,255,1);
setup_ccp1(CCP_PWM);
set_pwm1_duty(1023);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);

// TODO: USER CODE!!

}

[Ttelmah]

Two things:
Unless you add:

while (TRUE);

at the end of your code, the processor will go to sleep, and no output at all will occur.

Second, you need a lower duty cycle, to see any pulse.
Set_pwm1_duty(512L);

will give a square wave, which will be easier to see. The 'L', is not necessary with 512 (since it is above 255), but ensures that the code 'sees' a 'long', no matter what value is given, and treats the number as such.

Best Wishes