---
name: "pcfadc"
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/pcfadc"
---

# pcfadc(4)

Philips PCF8591 temperature sensor

## NAME

**pcfadc** – Philips PCF8591 temperature sensor

## SYNOPSIS

**pcfadc\* at iic?**

## DESCRIPTION

The **pcfadc** driver supports the PCF8591 I2C analog to digital converter, making its readings available through a [sysctl(8)](/sysctl/8.md) interface.

The driver reads up to four A/D lines configured as temperature inputs. Sensor names, type and calibration information are read from OpenFirmware.

## SEE ALSO

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

## HISTORY

The **pcfadc** driver first appeared in OpenBSD 3.9.

## AUTHORS

The **pcfadc** driver was written by Damien Miller ⟨*djm@openbsd.org*⟩.