.\"
.\" SPDX-License-Identifier: BSD-2-Clause
.\"
.\" $NetBSD: uchcom.4,v 1.2 2008/04/30 13:10:54 martin Exp $
.\"
.\" Copyright (c) 2007 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Takuya SHIOZAKI (tshiozak@netbsd.org).
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd June 25, 2025
.Dt UCHCOM 4
.Os
.Sh NAME
.Nm uchcom
.Nd WinChipHead CH9102/CH343/CH341/CH340 USB to serial UART driver
.Sh SYNOPSIS
.Cd "device usb"
.Cd "device ucom"
.Cd "device uchcom"
.Pp
In
.Xr rc.conf 5 :
.Cd kld_list="uchcom"
.Pp
In
.Xr sysctl.conf 5 :
.Cd hw.usb.uchcom.debug=1
.Sh DESCRIPTION
The
.Nm
driver provides support for the WinChipHead USB to serial UART adapters.
If the appropriate hardware is detected,
the driver will be loaded automatically by
.Xr devmatch 8 .
To load the driver manually, add it to the
.Ic kld_list
in
.Xr rc.conf 5 ,
or use
.Xr kldload 8
at runtime.
The device is accessed through the
.Xr ucom 4
driver, which makes it behave like a
.Xr tty 4 .
.Pp
Call out through this interface with applications like
.Xr cu 1
or
.Xr tip 1 .
.Sh HARDWARE
The
.Nm
driver supports the following USB to serial UART controllers:
.Pp
.Bl -bullet -compact
.It
WinChipHead CH9102 (max 6Mbps)
.It
WinChipHead CH343 (max 6Mbps)
.It
WinChipHead CH341 (max 2Mbps)
.It
WinChipHead CH340 (max 2Mbps)
.El
.Sh SYSCTL VARIABLES
These settings can be entered in the
.Xr loader 8
prompt, set in
.Xr loader.conf 5 ,
.Xr sysctl.conf 5 ,
or changed at runtime with
.Xr sysctl 8 :
.Bl -tag -width "hw.usb.uchcom.debug"
.It Va hw.usb.uchcom.debug
Enable debugging messages, default
.Ql 0
.El
.Sh FILES
.Bl -tag -width "/dev/ttyU*.init" -compact
.It Pa /dev/ttyU*
for callin ports
.It Pa /dev/ttyU*.init
.It Pa /dev/ttyU*.lock
corresponding callin initial-state and lock-state devices
.Pp
.It Pa /dev/cuaU*
for callout ports
.It Pa /dev/cuaU*.init
.It Pa /dev/cuaU*.lock
corresponding callout initial-state and lock-state devices
.El
.Sh SEE ALSO
.Xr cu 1 ,
.Xr tty 4 ,
.Xr ucom 4 ,
.Xr usb 4
.Sh HISTORY
The
.Nm
driver appeared in
.Fx 8.0
from
.Nx 5.0 .