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{{DISPLAYTITLE:如何发送或接收CAN数据}}
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=如何发送或接收 CAN 数据=
 +
==目的==
 +
: 本文介绍如何使用 can-utils [1 ]包在 SocketCAN 接口上发送/接收数据。
 +
: can-utils 包含一些用于 Linux®SocketCAN 子系统的用户空间实用程序。它已集成在STM32微处理器系列的 SDK 中。在此示例中，仅使用到 cansend 和 candump，但软件包中还提供了许多其他的工具。
 +
 +
==准备条件==
 +
: 至少需要两个设备才能在 CAN 网络上进行通信。要实现这种配置，请在同一 CAN 总线上连接两个设备。然后，从一个节点发送数据，并在另一节点上接收数据。
 +
: 在开始通信之前，必须在每块板上配置并启用 SocketCAN 接口。[https://wiki.st.com/stm32mpu/wiki/How_to_set_up_a_SocketCAN_interface 请参阅如何设置 SocketCAN 接口]。
 +
 +
==在CAN总线上发送数据==
 +
: 要发送单个帧，请使用 cansend 实用程序：
 +
<syntaxhighlight lang="bash">
 +
Board $> cansend can0 123#1122334455667788
 +
</syntaxhighlight>
 +
: 获取 cansend 实用程序中的使用帮助信息：
 +
<syntaxhighlight lang="bash">
 +
Board $> cansend -h
 +
Usage: cansend <device> <can_frame>
 +
</syntaxhighlight>
 +
: 如果出现帧错误，请尝试下面的操作：
 +
<syntaxhighlight lang="bash">
 +
    <can_id>#{R|data}          for CAN 2.0 frames
 +
  <can_id>##<flags>{data}    for CAN FD frames
 +
 +
<can_id> can have 3 (SFF) or 8 (EFF) hex chars
 +
{data} has 0..8 (0..64 CAN FD) ASCII hex-values (optionally separated by '.')
 +
<flags> a single ASCII Hex value (0 .. F) which defines canfd_frame.flags
 +
 +
e.g. 5A1#11.2233.44556677.88/123#DEADBEEF/5AA#/123##1/213##311
 +
  1F334455#1122334455667788/123#R for remote transmission request.
 +
</syntaxhighlight>
 +
==在CAN总线上接收数据==
 +
: 要实时显示总线上收到的消息列表，请使用 candump 实用程序：
 +
<syntaxhighlight lang="bash">
 +
Board $> candump can0
 +
can0  123  [8] 11 22 33 44 55 66 77 88
 +
</syntaxhighlight>
 +
: 在 candump 实用程序上获取帮助信息：
 +
<syntaxhighlight lang="bash">
 +
Board $> candump -h
 +
 +
Usage: candump [options] <CAN interface>+
 +
  (use CTRL-C to terminate candump)
 +
 +
Options: -t <type>  (timestamp: (a)bsolute/(d)elta/(z)ero/(A)bsolute w date)
 +
        -c          (increment color mode level)
 +
        -i          (binary output - may exceed 80 chars/line)
 +
        -a          (enable additional ASCII output)
 +
        -S          (swap byte order in printed CAN data[] - marked with '`' )
 +
        -s <level>  (silent mode - 0: off (default) 1: animation 2: silent)
 +
        -b <can>    (bridge mode - send received frames to <can>)
 +
        -B <can>    (bridge mode - like '-b' with disabled loopback)
 +
        -u <usecs>  (delay bridge forwarding by <usecs> microseconds)
 +
        -l          (log CAN-frames into file. Sets '-s 2' by default)
 +
        -L          (use log file format on stdout)
 +
        -n <count>  (terminate after receiption of <count> CAN frames)
 +
        -r <size>  (set socket receive buffer to <size>)
 +
        -D          (Don't exit if a "detected" can device goes down.
 +
        -d          (monitor dropped CAN frames)
 +
        -e          (dump CAN error frames in human-readable format)
 +
        -x          (print extra message infos, rx/tx brs esi)
 +
        -T <msecs>  (terminate after <msecs> without any reception)
 +
 +
Up to 16 CAN interfaces with optional filter sets can be specified on the commandline in the form: <ifname>[,filter]*
 +
 +
Comma separated filters can be specified for each given CAN interface:
 +
<can_id>:<can_mask> (matches when <received_can_id> & mask == can_id & mask)
 +
<can_id>~<can_mask> (matches when <received_can_id> & mask != can_id & mask)
 +
#<error_mask>      (set error frame filter, see include/linux/can/error.h)
 +
[j|J]              (join the given CAN filters - logical AND semantic)
 +
 +
CAN IDs, masks and data content are given and expected in hexadecimal values.
 +
When can_id and can_mask are both 8 digits, they are assumed to be 29 bit EFF.
 +
Without any given filter all data frames are received ('0:0' default filter).
 +
 +
Use interface name 'any' to receive from all CAN interfaces.
 +
 +
Examples:
 +
candump -c -c -ta can0,123:7FF,400:700,#000000FF can2,400~7F0 can3 can8
 +
candump -l any,0~0,#FFFFFFFF    (log only error frames but no(!) data frames)
 +
candump -l any,0:0,#FFFFFFFF    (log error frames and also all data frames)
 +
candump vcan2,92345678:DFFFFFFF (match only for extended CAN ID 12345678)
 +
candump vcan2,123:7FF (matches CAN ID 123 - including EFF and RTR frames)
 +
candump vcan2,123:C00007FF (matches CAN ID 123 - only SFF and non-RTR frames)
 +
</syntaxhighlight>
 +
==硬件自检==
 +
: 在内部环回测试模式下，FDCAN将发送的消息作为接收消息进行处理。此选项用于硬件自检（无需在 CAN 总线上连接外部 CAN 节点）。
 +
 +
: 要在回环模式下配置和启用 SocketCAN，请执行以下操作：
 +
<syntaxhighlight lang="bash">
 +
Board $> ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on loopback on
 +
[ 78.700698] m_can 4400e000.can can0: bitrate error 0.3%
 +
[ 78.704568] m_can 4400e000.can can0: bitrate error 1.6%
 +
[ 78.710140] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
 +
</syntaxhighlight>
 +
: 要在同一接口上发送和接收消息，请按照下列步骤操作：
 +
<syntaxhighlight lang="bash">
 +
Board $> candump can0 -L &
 +
[1] 475
 +
Board $> cansend can0 300#AC.AB.AD.AE.75.49.AD.D1
 +
(1539944874.949723) can0 300#ACABADAE7549ADD1
 +
(1539944874.949683) can0 300#ACABADAE7549ADD1
 +
</syntaxhighlight>
 +
==参考==
 +
: [https://github.com/linux-can/can-utils/blob/master/README.md CAN-UTILS信息]，github.com上的README
 +
 
[[Category:Linux_Operating_System]]
 
[[Category:Linux_Operating_System]]
 
[[Category:Networking]]
 
[[Category:Networking]]
 
[[Category:Netdev]]
 
[[Category:Netdev]]
 
[[Category:CAN]]
 
[[Category:CAN]]

2020年1月6日 (一) 15:01的最新版本


如何发送或接收 CAN 数据

目的

本文介绍如何使用 can-utils [1 ]包在 SocketCAN 接口上发送/接收数据。
can-utils 包含一些用于 Linux®SocketCAN 子系统的用户空间实用程序。它已集成在STM32微处理器系列的 SDK 中。在此示例中，仅使用到 cansend 和 candump，但软件包中还提供了许多其他的工具。

准备条件

至少需要两个设备才能在 CAN 网络上进行通信。要实现这种配置，请在同一 CAN 总线上连接两个设备。然后，从一个节点发送数据，并在另一节点上接收数据。
在开始通信之前，必须在每块板上配置并启用 SocketCAN 接口。请参阅如何设置 SocketCAN 接口。

在CAN总线上发送数据

要发送单个帧，请使用 cansend 实用程序：
	Board $> cansend can0 123#1122334455667788
获取 cansend 实用程序中的使用帮助信息：
	Board $> cansend -h
	Usage: cansend <device> <can_frame>
如果出现帧错误，请尝试下面的操作：
	    <can_id>#{R|data}          for CAN 2.0 frames
	  	<can_id>##<flags>{data}    for CAN FD frames

	<can_id> can have 3 (SFF) or 8 (EFF) hex chars
	{data} has 0..8 (0..64 CAN FD) ASCII hex-values (optionally separated by '.')
	<flags> a single ASCII Hex value (0 .. F) which defines canfd_frame.flags

	e.g. 5A1#11.2233.44556677.88/123#DEADBEEF/5AA#/123##1/213##311
	   1F334455#1122334455667788/123#R for remote transmission request.

在CAN总线上接收数据

要实时显示总线上收到的消息列表，请使用 candump 实用程序：
	Board $> candump can0
	can0  123   [8] 11 22 33 44 55 66 77 88
在 candump 实用程序上获取帮助信息：
	Board $> candump -h

	Usage: candump [options] <CAN interface>+
	   (use CTRL-C to terminate candump)

	Options: -t <type>   (timestamp: (a)bsolute/(d)elta/(z)ero/(A)bsolute w date)
	         -c          (increment color mode level)
	         -i          (binary output - may exceed 80 chars/line)
	         -a          (enable additional ASCII output)
	         -S          (swap byte order in printed CAN data[] - marked with '`' )
	         -s <level>  (silent mode - 0: off (default) 1: animation 2: silent)
	         -b <can>    (bridge mode - send received frames to <can>)
	         -B <can>    (bridge mode - like '-b' with disabled loopback)
	         -u <usecs>  (delay bridge forwarding by <usecs> microseconds)
	         -l          (log CAN-frames into file. Sets '-s 2' by default)
	         -L          (use log file format on stdout)
	         -n <count>  (terminate after receiption of <count> CAN frames)
	         -r <size>   (set socket receive buffer to <size>)
	         -D          (Don't exit if a "detected" can device goes down.
	         -d          (monitor dropped CAN frames)
	         -e          (dump CAN error frames in human-readable format)
	         -x          (print extra message infos, rx/tx brs esi)
	         -T <msecs>  (terminate after <msecs> without any reception)

	Up to 16 CAN interfaces with optional filter sets can be specified on the commandline in the form: <ifname>[,filter]*

	Comma separated filters can be specified for each given CAN interface:
	 <can_id>:<can_mask> (matches when <received_can_id> & mask == can_id & mask)
	 <can_id>~<can_mask> (matches when <received_can_id> & mask != can_id & mask)
	 #<error_mask>       (set error frame filter, see include/linux/can/error.h)
	 [j|J]               (join the given CAN filters - logical AND semantic)

	CAN IDs, masks and data content are given and expected in hexadecimal values.
	When can_id and can_mask are both 8 digits, they are assumed to be 29 bit EFF.
	Without any given filter all data frames are received ('0:0' default filter).

	Use interface name 'any' to receive from all CAN interfaces.

	Examples:
	candump -c -c -ta can0,123:7FF,400:700,#000000FF can2,400~7F0 can3 can8
	candump -l any,0~0,#FFFFFFFF    (log only error frames but no(!) data frames)
	candump -l any,0:0,#FFFFFFFF    (log error frames and also all data frames)
	candump vcan2,92345678:DFFFFFFF (match only for extended CAN ID 12345678)
	candump vcan2,123:7FF (matches CAN ID 123 - including EFF and RTR frames)
	candump vcan2,123:C00007FF (matches CAN ID 123 - only SFF and non-RTR frames)

硬件自检

在内部环回测试模式下，FDCAN将发送的消息作为接收消息进行处理。此选项用于硬件自检（无需在 CAN 总线上连接外部 CAN 节点）。
要在回环模式下配置和启用 SocketCAN，请执行以下操作：
	Board $> ip link set can0 up type can bitrate 1000000 dbitrate 2000000 fd on loopback on
	[ 78.700698] m_can 4400e000.can can0: bitrate error 0.3%
	[ 78.704568] m_can 4400e000.can can0: bitrate error 1.6%
	[ 78.710140] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready
要在同一接口上发送和接收消息，请按照下列步骤操作：
	Board $> candump can0 -L &
	[1] 475
	Board $> cansend can0 300#AC.AB.AD.AE.75.49.AD.D1
	(1539944874.949723) can0 300#ACABADAE7549ADD1
	(1539944874.949683) can0 300#ACABADAE7549ADD1

参考

CAN-UTILS信息，github.com上的README
取自“http://wiki.100ask.org/index.php?title=How_to_send_or_receive_CAN_data&oldid=6022”