---
name: "wbwd"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/wbwd"
---

# wbwd(4)

device driver for Winbond/Nuvoton Super I/O chips watchdog timer

## NAME

**wbwd** – device driver for Winbond/Nuvoton Super I/O chips watchdog timer

## SYNOPSIS

**device** **superio** **device** **wbwd**

In [loader.conf(5)](/loader.conf/5.md): **wbwd\_load="YES"**

In [loader.conf(5)](/loader.conf/5.md) or [sysctl.conf(5)](/sysctl.conf/5.md): **dev.wbwd.0.timeout\_override** **dev.wbwd.0.debug\_verbose** **dev.wbwd.0.debug**

## HARDWARE

The **wbwd** driver provides [watchdog(4)](/watchdog/4.md) support for the watchdog interrupt timer present on at least the following Super I/O chips:

- Winbond 83627HF/F/HG/G

- Winbond 83627S

- Winbond 83697HF

- Winbond 83697UG

- Winbond 83637HF

- Winbond 83627THF

- Winbond 83687THF

- Winbond 83627EHF

- Winbond 83627DHG

- Winbond 83627UHG

- Winbond 83667HG

- Winbond 83627DHG-P

- Winbond 83667HG-B

- Nuvoton NCT6775

- Nuvoton NCT6776

- Nuvoton NCT6102

- Nuvoton NCT6779

- Nuvoton NCT6791

- Nuvoton NCT6792

## SYSCTL VARIABLES

The **wbwd** driver provides the following options as [sysctl(8)](/sysctl/8.md) variables.

- *dev.wbwd.0.timeout\_override*

  This variable allows to program the timer to a value independent on the one provided by the [watchdog(4)](/watchdog/4.md) framework while still relying on the regular updates from e.g. [watchdogd(8)](/watchdogd/8.md). This is particularly useful if your system provides multiple watchdogs and you want them to fire in a special sequence to trigger an NMI after a shorter period than the reset timeout for example. The value set must not be lower than the sleep time of [watchdogd(8)](/watchdogd/8.md). A value of 0 disables this feature and the timeout value provided by [watchdog(4)](/watchdog/4.md) will be used.

- *dev.wbwd.0.debug\_verbose*

  If set this sysctl will tell the driver to log its current state before and after the timer reset on each invocation from [watchdog(9)](/watchdog/9.md) to the kernel message buffer for debugging.

- *dev.wbwd.0.debug*

  This read-only value gives the state of some registers on last update.

The **wbwd** driver also provides further sysctl options that are hidden by default. See the source code for more information.

## SEE ALSO

[superio(4)](/superio/4.md), [watchdog(4)](/watchdog/4.md), [device.hints(5)](/device.hints/5.md), [watchdog(8)](/watchdog/8.md), [watchdogd(8)](/watchdogd/8.md), [watchdog(9)](/watchdog/9.md)

## HISTORY

The **wbwd** driver first appeared in FreeBSD 10.0.

## AUTHORS

This manual page was written by Bjoern A. Zeeb ⟨*bz@FreeBSD.org*⟩.