pwm+pic

Guest · Posted: Sun Aug 06, 2006 12:19 pm

hi
i want to make a 120khz pwm with timer2 of pic16f877a and with 7.67375mhz cristal and duty cycle 50% in ccs software.
please help me
thanks a lot

Ttelmah · Guest

It'll actually be 119902Hz (you can't quite do 120KHz with the hardware, given your clock frequency), but the required setup lines are:

setup_timer_2(T2_DIV_BY_1,15,1);
setup_ccp1(CCP_PWM);
set_pwm1_duty(32L);

Note the 'L'. This is important, since it makes the code use the extra two bits in the second register for setting the duty cycle.

Best Wishes

Guest · Posted: Mon Aug 07, 2006 11:59 am

Hi
thanks alot for your guidance.
best regards

Moeini · Joined: 08 Aug 2006 Posts: 9

Hi
Kindly please explain for me about numbers in : setup_timer_2(t2_div_by_1,15,1)
and set_pwm1_duty(32L)
Best Regards

Ttelmah · Guest

Get AN564 from Microchip, and learn how the hardware you are trying to use works.

Best Wishes