PWM
An IO class that provides access to the pulse-width modulation capability of pins.
Constructor
PWM
Creates a new PWM object instance.
PWM(options)Parameters
options
An object of properties used to construct the class.
pin- a pin specifier indicating the GPIO pin to operate as PWM output.
hz(optional) - a number specifying the requested frequency of the PWM output in hertz. The default is device dependent.
Exceptions
If the constructor requires a resource that is already in use — whether by a script or the native host — an Error exception is thrown.
Instance Properties
Includes properties of the IO Class Pattern. Specific to this class:
format
Always returns "number". The string value set by the constructor options or by the script at any time to change how it reads data.
resolution
Read-only property indicates the number of bits of resolution in values passed to the write method, e.g 10.
hz
Read-only property indicates the frequency of the PWM.
Instance Methods
write
Sets the current count on the IO instance.
write(value)Parameters
value
A number 0 and a maximum value based on the resolution of the PWM output.
Examples
The class can be imported from the embedded namespace or found on the host device global object:
import PWM from "embedded:io/pwm";const PWM = device.io.PWM;Hello Dimming Blinky
This example instantiates a PWM output to control an LED based on the global device pin names and fade it on or off using System.setInterval.
const led = new device.io.PWM({ pin: device.io.led,});
const range = (2 ** led.resolution) - 1;let step = 5;let value = 0;
System.setInterval(() => { value += step;
if (value < 0 || value > range) { step *= -1; value += step; }
led.write(value)}, 5)