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.\" $OpenBSD: iic.4,v 1.6 2005/11/16 06:26:14 deraadt Exp $
.\"
.\" Copyright (c) 2004 Alexander Yurchenko <grange@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd May 15, 2004
.Dt IIC 4
.Os
.Sh NAME
.Nm iic
.Nd Inter IC (I2C) bus
.Sh SYNOPSIS
.Cd "iic* at gscsio?"
.Sh DESCRIPTION
.Tn I2C
is a two-wire bus developed by Philips used for connecting
integrated circuits.
It is commonly used for connecting devices such as EEPROMs,
temperature sensors, fan controllers, real-time clocks, tuners,
and other types of integrated circuits.
.Pp
The
.Nm
driver provides a uniform programming interface layer between
.Tn I2C
master controllers and various
.Tn I2C
slave devices.
Each
.Tn I2C
master controller attaches an
.Nm
framework; several slave devices can then be attached to the
.Nm
bus.
.Pp
All
.Tn I2C
slave devices are uniquely identified by the address on the bus.
The master accesses a particular slave device using its address.
Device addresses should be specified in the kernel configuration file
with the
.Cd addr
locator.
.Pp
System Management Bus (SMBus) protocol is also supported by emulating
it with the
.Tn I2C
commands.
.Sh SUPPORTED MASTERS
.Bl -tag -width 10n -offset ind -compact
.It Xr gscsio 4
National Semiconductor Geode SC1100 Super I/O ACCESS.bus
.It Xr maciic 4
Apple Inter IC (I2C) bus
.El
.Pp
.Sh SUPPORTED SLAVES
.Bl -tag -width 10n -offset ind -compact
.It Xr adc 4
Analog Devices AD7416/AD7417/7418 temperature sensor
.It Xr admtmp 4
Analog Devices ADM1030 temperature sensor
.It Xr lmenv 4
National Semiconductor LM87 temperature sensor
.It Xr lmtemp 4
National Semiconductor LM75/LM77 temperature sensor
.It Xr maxds 4
Maxim DS1631 temperature sensor
.It Xr maxtmp 4
Maxim MAX6690 temperature sensor
.It Xr pcagpio 4
Philips PCA9554 gpio
.It Xr tsl 4
TAOS TSL2560/61 light-to-digital converter
.El
.Sh SEE ALSO
.Xr intro 4 ,
.Xr iic 9
.Sh HISTORY
The
.Tn I2C
framework first appeared in
.Nx 2.0 .
.Ox
support was added in
.Ox 3.6 .
.Sh AUTHORS
The
.Tn I2C
framework was written by
Steve C. Woodford and Jason R. Thorpe for
.Nx
and then ported to
.Ox
by
.An Alexander Yurchenko Aq grange@openbsd.org .
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