Hardware PWM & Servos APICopy Anchor Link

The PWM (or System.pwm) object provides control over the ESP32's native LED Control (LEDC) peripheral. It offers 16 independent PWM channels with configurable frequencies up to 40 MHz and resolution up to 16 bits.

Firmware timer configurations are documented in the KryonOS GitHub Repository.

1. Hardware PWM ChannelsCopy Anchor Link

PWM.attach(pin, channel, freq, resolution)Copy Anchor Link

Binds a GPIO pin to a hardware LEDC PWM timer channel.

• Parameters:
  • pin (Integer): GPIO pin number.
  • channel (Integer, optional): PWM channel (0 to 15).
  • freq (Integer, optional): Base frequency in Hz (default 5000).
  • resolution (Integer, optional): Timer bit resolution (1 to 16, default 8 for 0-255 range).
• Returns: Boolean (true if attached successfully).

PWM.write(pin, duty) / PWM.writeDuty(pin, duty)Copy Anchor Link

Updates the output duty cycle on an attached pin.

• Parameters:
  • pin (Integer)
  • duty (Integer): 0 to (2^resolution - 1). For 8-bit resolution, 0 to 255.
• Returns: Boolean

PWM.detach(pin)Copy Anchor Link

Releases the PWM channel and resets the pin to high-impedance input mode.

• Parameters: pin (Integer)
• Returns: Boolean

2. Servo Motor ControlCopy Anchor Link

The PWM engine includes a hardware servo generator running at 50 Hz with 500–2500 microsecond pulse widths.

PWM.writeServo(pin, angle)Copy Anchor Link

Commands a standard hobby servo (e.g. SG90, MG996R) to rotate to a target angle.

• Parameters:
  • pin (Integer): Servo signal pin.
  • angle (Float or Integer): Target angle between 0 and 180 degrees.
• Returns: Boolean

// Controlling a Servo on GPIO 14
var SERVO_PIN = 14;

// Sweep servo from 0 to 180 degrees
for (var deg = 0; deg <= 180; deg += 10) {
  PWM.writeServo(SERVO_PIN, deg);
  System.delay(50);
}

3. Piezo Buzzer & Tone GenerationCopy Anchor Link

PWM.writeTone(pin, freq, duration)Copy Anchor Link

Generates an audible square-wave tone on a connected passive buzzer.

• Parameters:
  • pin (Integer): Buzzer pin.
  • freq (Integer): Tone frequency in Hz (e.g. 440 for A4, 1000 for beep). Set to 0 to stop tone.
  • duration (Integer, optional): Duration in milliseconds.
• Returns: Boolean

// Play an alert sound on GPIO 25
function playBeep() {
  PWM.writeTone(25, 2000, 100);
  System.delay(120);
  PWM.writeTone(25, 3000, 150);
}