The PWM pins on UNO have an 8-bit resolution. This gives us 256 discrete duty cycles, since 2^8 = 256. Example:

2 bit means 4 possible duty cycles. For PWM, they would be: 0, 33.33%, 66.66%, and 100%. Similarly, 4-bit means 16 duty cycles, and 8-bit means 256 cycles.

Now why does the PWM range from 0 to 255 and not 256?

Because when you count 0, the total values from 0 to 255 are 256.

In Arduino, the analogWrite function is used to generate a PWM signal on a specified pin. The value parameters ranging from (0-255) you provide determines the duty cycle of the  PWM signal.

• Value of 0: This means the pin is always off (0% duty cycle).
• Value of 255: This means the pin is always on (100% duty cycle).
• Values between 0 and 255: These values correspond to duty cycles between 0% and 100%. For example, a value of 127 would create a 50% duty cycle.

This allows for precise control of analog devices, such as LEDs or motors, using digital signals.

I'm trying to understand why the analogWrite function in Arduino requires a value between 0 and 255 for PWM (Pulse Width Modulation). What does this range actually signify in terms of how PWM works? Why specifically these values, and how does it relate to controlling the output?

thank you