How to write pwm using picbasic pro?

[electroken]

You didn't mention which type of PWM you wanted, HWPM for continous PWM, or regular. Here is a quickie program that flashes a LED from full bright to dimly lit. It's good for an indication of some kind.
Install a LED on portb.0

T var byte' set-up the loop variable
For t=1 to 20' amount of bright/dim  flashes
portb.0=1:pause 90:portb.0=0' full bright ON time then turn OFF---experiment with the ON time.
PWM portb.0,20,80' the 20 is LED brightness, the 80 is it's ON time--Again experiment with the numbers, try changing the 20 to 50.
TRISb=0' Once PWM is used on a pin, then that pin only wants PWM to be used. The TRISb resets the pin back to normal output.
next t' end of loop

If you had inputs on portb, like portb.1, and portb.2, then use TRISb=%00000110
.
While PWM is operating, nothing else is being done. Same way with SOUND. When using a servo, when PWM stops, the servo no longer gets data causing it to lose it's position if it was under a load. To correct this you would need to use the HWPM.
Hope this helped.
Electroken