Việc dùng PWM trong pic 16f877a

[phamtrieu138]

#include "C:\Documents and Settings\User\My Documents\thu pwm\hhff.h"
#byte portc=0x07
#use fast_io(c)
void bam()
{
set_pwm1_duty(800);
set_pwm2_duty(677);
}

void main()
{

setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(FALSE);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_INTERNAL|T1_DIV_BY_1);
setup_timer_2(T2_DIV_BY_1,255,1);
setup_ccp1(CCP_PWM);
setup_ccp2(CCP_PWM);
setup_comparator(NC_NC_NC_NC);
setup_vref(FALSE);
set_tris_c(0);
bam();
while (1)
{
}
}

sao c1,c2 ra toàn bằng 0 vậy. có khai báo gì đặc biệt hay phai treo trở ở chân c1,c2 vậyy??????