---
name: "fcu"
section: "4"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/fcu"
---

# fcu(4)

Apple Fan Control Unit sensor device

## NAME

**fcu** – Apple Fan Control Unit sensor device

## SYNOPSIS

**fcu\* at iic?**

## DESCRIPTION

The **fcu** driver provides support for the Apple Fan Control Unit (FCU). The device controls and monitors fans found in some Apple machines. Fan speed readings and PWM settings are made available through the [sysctl(8)](/sysctl/8.md) interface.

## SEE ALSO

[iic(4)](/iic/4.md), [intro(4)](/intro/4.md), [sensorsd(8)](/sensorsd/8.md), [sysctl(8)](/sysctl/8.md)

## AUTHORS

The **fcu** driver was written by Theo de Raadt ⟨*deraadt@openbsd.org*⟩.