PWM question from a beginner

Projects Programming
1

So I'm new to the arduino and I"m trying to understand the programming for PWM. What I want to know is if I change a pin's frequency, will that effect how analogWrite() sets a duty cycle?

For example, Can I set pin 9's frequency to 31.250kHz like so:

void setup() 
{Serial.begin(9600);
  pinMode(3,OUTPUT);
    TCCR2B = TCCR2B & 0b11111000 | 0x01;  
}

Then manipulate the duty cycle to 20% using analogWrite(), like this:

void loop()
{analogWrite(3,0.20*255)
}

or does changing the frequency cause the value of 255 to change? ...Or something else entirely?

2

Changing the frequency will not change the parameters of analogWrite. It will still only operate in a range of ~0-255.