文章目录

can-utils提供了一系列实用的命令行工具,可以方便的调试CAN总线数据。这里主要记录各个工具的用法

candump: 用于查看CAN数据cansend: 用于发送数据到CAN总线canbusload: 用于查看CAN总线使用率

candump

命令行中输入candump然后回车可以打印出该工具的详细用法

candump - dump CAN bus traffic.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) -H (read hardware timestamps instead of system timestamps) -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 specifiedon the commandline in the form: <ifname>[,filter]*Filters: 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 can8candump -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)

常用的几种情况

直接使用如下指令查看对应CAN设备总线上的所有数据：

candump can1 查看特定ID的CAN数据

candump can1,181:7FF,281:7FF // candump <can_devices>,<can_id>:<can_mask>

这里是只监听CANID为0x181,0x281的数据。（知识点：CAN标准帧ID为11位，对应的掩码为0x7FF。CAN扩展帧ID为29位，对应的掩码为0x1FFFFFFF）

添加时间戳参数

candump can1 -tA

例如：

cansend

Usage: cansend - simple command line tool to send CAN-frames via CAN_RAW sockets.Usage: cansend <device> <can_frame>.<can_frame>: <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.flagsExamples: 5A1#11.2233.44556677.88 / 123#DEADBEEF / 5AA# / 123##1 / 213##311 1F334455#1122334455667788 / 123#R for remote transmission request. 发送数据到CAN总线

cansend can1 201#1122334455667788 //发送 11 22 33 44 55 66 77 88到总线cansend can1 000#0100

canbusload

canbusload - monitor CAN bus load.Usage: canbusload [options] <CAN interface>+ (use CTRL-C to terminate canbusload)Options: -t (show current time on the first line) -c (colorize lines) -b (show bargraph in 5% resolution) -r (redraw the terminal - similar to top) -i (ignore bitstuffing in bandwidth calculation) -e (exact calculation of stuffed bits)Up to 16 CAN interfaces with mandatory bitrate can be specified on thecommandline in the form: <ifname>@<bitrate>The bitrate is mandatory as it is needed to know the CAN bus bitrate tocalcultate the bus load percentage based on the received CAN frames.Due to the bitstuffing estimation the calculated busload may exceed 100%.For each given interface the data is presented in one line which contains:(interface) (received CAN frames) (used bits total) (used bits for payload)Examples:user$> canbusload can0@100000 can1@500000 can2@500000 can3@500000 -r -t -b -c 查看CAN1总线负载

canbusload can1@500000