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

# atkbdc(4)

the AT keyboard controller interface

## NAME

**atkbdc** – the AT keyboard controller interface

## SYNOPSIS

**options KBD\_RESETDELAY=N** **options KBD\_MAXWAIT=N** **options KBD\_DELAY1=N** **options KBD\_DELAY2=N** **options KBDIO\_DEBUG=N** **device atkbdc**

In */boot/device.hints*: **hint.atkbdc.0.at="isa"** **hint.atkbdc.0.port="0x060"**

## DESCRIPTION

The keyboard controller **atkbdc** provides I/O services for the AT keyboard and PS/2 mouse style pointing devices. This controller is required for the keyboard driver **atkbd** and the PS/2 pointing device driver **psm**.

There can be only one **atkbdc** device configured in the system.

## DRIVER CONFIGURATION

### Kernel Configuration Options

The following kernel configuration options can be used to control the **atkbdc** driver. They may be set in the kernel configuration file (see [config(8)](/config/8.md)).

- *KBD\_RESETDELAY=X*, *KBD\_MAXWAIT=Y*

  The keyboard driver **atkbd** and the pointing device driver **psm** may ask the **atkbdc** driver to reset these devices during the boot process. It sometimes takes a long time before these devices respond to the reset command. These options control how long the **atkbdc** driver should wait before eventually giving up -- the driver will wait *X* \* *Y* msecs at most. If the drivers seem unable to detect devices, you may want to increase these values. The default values are 200 msec for *X* and 5 for *Y*.

- *KBD\_DELAY1=X,* *KBD\_DELAY2=Y*

  DELAY1 sets the initial key repeat delay to *X*. The default value is 500ms. DELAY2 sets the key repeat delay to *Y*. The default value is 100ms.

- *KBDIO\_DEBUG=N*

  Sets the debug level to *N*. The default value is zero, which suppresses all debugging output.

## SEE ALSO

[atkbd(4)](/atkbd/4.md), [psm(4)](/psm/4.md), [config(8)](/config/8.md)

## HISTORY

The **atkbdc** driver first appeared in FreeBSD 3.1. It is based on the kbdio module in FreeBSD 2.2.

## AUTHORS

The kbdio module, the **atkbdc** driver and this manual page were written by Kazutaka Yokota ⟨*yokota@FreeBSD.org*⟩.