Archives: Pwm

PWM input support

The new features and capababilities for moteus just keep coming! Here is another relatively straightforward one available in firmware release 2026-01-21, support for PWM (pulse-width-modulated) inputs. If an appropriate pin is configured, moteus can report the period and duty cycle of a PWM input to applications. This can be used to monitor the fan RPM for the moteus cooling fans on moteus-c1, moteus-n1, or moteus-x1, or could be used to read the value of a RC receiver output. Read on to learn how to use it and what the limitations are:

PWM output with moteus

Here’s a bit more in-depth discussion of a yet another new feature from moteus firmware release 2024-10-29: pulse width modulated output on auxiliary ports.

A pulse width modulated signal is a logic level signal of a fixed frequency, where the duty cycle, or width of the pulse, is changed or modulated to communicate a scalar value. Obligatory Wikipedia diagram below:

The new feature does what it claims to do, in that a subset of auxiliary pins can now be configured to output a PWM signal. If so configured, the duty cycle can be controlled using either the diagnostic or register protocol.