嵌入式linux读写can简单示例
1、查看是否又can驱动
ifconfig –a
2、配置速率
ip link set can0 type cantq 125 prop-seg 6phase-seg1 7 phase-seg2 2 sjw 1
或者
ip link set can0 type can bitrate 125000
3、查看状态
ip -details link show can0
或者
ip -details -statistics link show can0
4、使能
ifconfig can0 up
c编程
需要先配置好速率并启动can
can.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <linux/can.h>
#include <linux/can/raw.h>
static int s;
static struct can_frame frame[2] = {
{
0}};
int can_init(char *dev)
{
struct sockaddr_can addr;
struct ifreq ifr;
s = socket(PF_CAN, SOCK_RAW, CAN_RAW);//创建套接字
strcpy(ifr.ifr_name, dev);
ioctl(s, SIOCGIFINDEX, &ifr); //指定 can设备
addr.can_family = AF_CAN;
addr.can_ifindex = ifr.ifr_ifindex;
bind(s, (struct sockaddr *)&addr, sizeof(addr));//将套接字与 can绑定
//禁用过滤规则，本进程不接收报文，只负责发送
//setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, NULL, 0);
//设置过滤规则
setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, &rfilter, sizeof(rfilter));
}
int can_send(unsigned int id, unsigned char *buf, char dlc)
{
int tmp = 0;
frame[0].can_id = id;
frame[0]. can_dlc = dlc;
while(tmp < dlc && tmp <= 8)
{
frame[0].data[tmp] = buf[tmp];
tmp++;
}
tmp = 0;
tmp = write(s, &frame[0], sizeof(frame[0])); //发送 frame[0]
if(nbytes != sizeof(frame[0]))
{
return -1;
}
}
int can_readrcv(struct can_frame *frame)
{
int tmp = 0;
tmp = read(s, &frame[1], sizeof(frame[1])); //接收报文
*frame = frame[1];
return tmp;
}
int can_close()
{
close(s);
return 0;
}
main.c
#include <stdio.h>
#include "can.h"
int main()
{
unsigned char txbuf[8] = "hello";
int tmp = 0;
struct can_frame f_tmp;
can_init("can0",);
while(1)
{
can_send(0x12, txbuff, 8);
tmp = can_readrcv(&f_tmp);
if(tmp > 0)
{
printf("id=%d,dlc=%d,"f_tmp.id,f_tmp.dlc);
char i = 0;
while(i < 8)
{
printf("%x ",f_tmp.data[i]);
}
printf("\n ");
}
sleep(1);
}
return 0;
}