127 lines
4.0 KiB
Groff
127 lines
4.0 KiB
Groff
.\" $NetBSD: canconfig.8,v 1.3 2017/05/29 08:46:23 wiz Exp $
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.\"
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.\" Copyright (c) 2017 Manuel Bouyer.
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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 ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd April 15, 2017
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.Dt CANCONFIG 8
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.Os
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.Sh NAME
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.Nm canconfig
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.Nd configure CAN network interface parameters
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.Sh SYNOPSIS
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.Nm
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.Fl a
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.Nm
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.Ar canif
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.Nm
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.Ar can
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.Ar command
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.Op Ar args ...
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.Sh DESCRIPTION
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The
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.Nm
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utility is used to configure CAN network interface parameters and retrieve
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CAN network interface parameters and status from the kernel.
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.Ss Timing
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The base time unit used to define the network bit rate is the time quanta (tq),
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its value is defined by the input clock frequency and the prescaler value
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as (1/ freq * prescaler).
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.Pp
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The network bit time is split in 4 segments:
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.Bl -tag -width "phase_seg1" -offset indent -compact
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.It sync_seg
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fixed to 1 tq
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.It prop_seg
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.It phase_seg1
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.It phase_seg2
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.El
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The network bit time is (1 + prop_seg + phase_seg1 + phase_seg2), in tq.
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The sample point is between phase_seg1 and phase_seg2.
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.Pp
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The receiver hardware is allowed to shorten prop_seg or phase_seg2 to
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resynchronize with the sender.
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The swj (Synchronisation Jump Width) parameter
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defines by how much the hardware can shorten these segments.
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.Pp
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Some hardware can use 3 sample points instead of one, and keep the majority as
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the final value.
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.Ss Options
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The options are as follows:
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.Bl -tag -width indent
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.It Fl a
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Display the status of all CAN devices present on the system.
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This flag is mutually exclusive with all other sub-commands.
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.El
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.Pp
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All other operations require that a CAN interface be specified.
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If a CAN interface is specified with no sub-commands,
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the status of that interface is displayed.
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.Pp
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The following sub-commands are available:
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.Bl -tag -width indent
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.It Cm up
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Start network operations on the interface.
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Requires that all timing parameters have been set.
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.It Cm down
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Stop network operations on the interface.
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.It Cm brp Ar value
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Set the value of the baud rate prescaler.
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.It Cm prop_seg Ar value
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Set the number of tq for the propagation segment.
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.It Cm phase_seg1 Ar value
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Set the number of tq for the phase segment 1.
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.It Cm phase_seg2 Ar value
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Set the number of tq for the phase segment 2.
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.It Cm sjw Ar value
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Set the number of tq for the Synchronisation Jump Width.
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.It Cm 3samples
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Enable triple-sampling.
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.It Cm -3samples
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Disable triple-sampling.
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.It Cm listenonly
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Enable listen-only mode.
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In this mode the controller is passive, and doesn't send ACKs on the bus.
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.It Cm -listenonly
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Disable listen-only mode.
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.It Cm loopback
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Enable loopback mode.
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In this mode, the controller doesn't expect ACK from the bus.
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.It Cm -loopback
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Disable loopback mode.
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.El
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.\".Sh EXAMPLES
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.\"TODO
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.Sh SEE ALSO
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.Xr ifconfig.if 5 ,
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.Xr ifconfig 8
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.Sh HISTORY
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The
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.Nm
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utility first appeared in
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.Nx 8.0 .
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.Sh AUTHORS
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This version of the
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.Nm
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utility was written by
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.An Manuel Bouyer .
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