motor control using potientiometer

Hi guys i need to control the speed of dc motor using pwm by potientiometer, USING PIC18F452/2580 i need to use pwm method and adc feature which constantly updating values in pwm duty cycle register , i want to ask which method will be used to constantly keep in touch with adc value, is any interrupt available or i have to rely on polling,

importantly i also need some working background of such a project , has some one got any other working idea,

Do you have to use an MCU?

I wouldn't bother, I'd just use a 555 or a couple of comparators.

Sounds like yet another school homework project.....

ADC is updated with new value from pot...PWM reads what new value is and adjusts output accordingly....check to see if ADC has been updated if not then pwm no change..