79 lines
2.7 KiB
Groff
79 lines
2.7 KiB
Groff
.\" Copyright (c) 1998, Nicolas Souchu
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd March 7, 2021
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.Dt SMBUS 4
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.Os
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.Sh NAME
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.Nm smbus
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.Nd System Management Bus
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.Sh SYNOPSIS
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.Cd "device smbus"
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.Pp
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.Cd "device iicsmb"
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.Sh DESCRIPTION
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The
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.Em smbus
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system provides a uniform, modular and architecture-independent
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system for the implementation of drivers to control various SMB devices
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and to utilize different SMB controllers (I2C, PIIX4, vm86...).
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.Sh System Management Bus
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The
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.Em System Management Bus
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is a two-wire interface through which simple power-related chips can communicate
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with rest of the system.
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It uses I2C as its backbone (see
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.Xr iicbus 4 ) .
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.Pp
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A system using SMB passes messages to and from devices instead of tripping
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individual control lines.
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.Pp
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With the SMBus, a device can provide manufacturer information, tell the
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system what its model/part number is, save its state for a suspend event,
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report different types of errors, accept control parameters, and return its
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status.
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.Pp
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The SMBus may share the same host device and physical bus as ACCESS bus
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components provided that an appropriate electrical bridge is provided
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between the internal SMB devices and external ACCESS bus devices.
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.Sh SEE ALSO
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.Xr iicbus 4 ,
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.Xr iicsmb 4 ,
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.Xr smb 4
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.Rs
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.%T The SMBus specification
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.%U http://www.smbus.org/specs/
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.Re
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.Sh HISTORY
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The
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.Nm
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manual page first appeared in
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.Fx 3.0 .
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.Sh AUTHORS
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This
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manual page was written by
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.An Nicolas Souchu .
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