maybe this ask is repeated but i need solve this special situation, i have an arm robot with 3 Freedon deegre, i want to control position of each motor with a raspberry pi 2 and L293D like a motor driver, i am source with 3.3 logic and 6 v source,but i don't know how to manipulate the PWM to change the action velocity like in arduino that only change the cycle(0-255) you have different velocity, thank
You do not modulate the PWM frequency to change motor speed.
You change the PWM dutycycle.
You set a dutycycle of 0% for off, 100% for fully on, 50% for half on, etc.
If the permitted dutycycle range is 0 to 255 that would be 0 (0%), 255 (100%), and 128 (50%).
If this isn't what you are asking you need to clarify your question.