Question about PWM and its frequency ~~ Need Help!

Hi there, I am trying to set a PWM pin to 8 khz output by bonescript, I also tried it through terminal ! but I am getting an error saying invalid argument. Here is my code :

var b = require(‘bonescript’);

var awPin = “P8_13”;
b.pinMode(awPin, b.OUTPUT);
b.analogWrite(awPin, 0.5, 8000);

I need to get that frequency so I can communicate with an ESC ( Electronic Speed Controller ). Not sure if PWM supports that frequency but please help me find a way to get it working. Thanks alot in advance.