Which feature should you include on a microcontroller to drive a servo motor?

• A. Pulse Width Modulation pin
• B. Analog-to-Digital converter
• C. Digital to Analog converter
• D. GPIO pins

Answer: (A)

A servo motor is controlled by a PWM signal, not a simple on/off voltage. Servos listen for pulses that repeat about every 20 milliseconds, and the width of each high pulse determines the angle: typically around 1 ms for one extreme, 1.5 ms for center, and 2 ms for the other extreme. A microcontroller with a PWM-capable pin can generate these precise, repeating pulses by using a timer in PWM mode, giving a stable period and a variable duty cycle to encode the position. This makes the control reliable and scalable.

Analog-to-Digital converters and Digital-to-Analog converters aren’t used to drive servo position—they convert signals between analog and digital forms, which isn’t what the servo requires for the control signal. General-purpose I/O pins can toggle high and low, but producing accurate, timing-critical PWM purely in software is error-prone and imprecise; a dedicated PWM output provides the consistent timing needed for proper servo control.