Jetson SPI转CAN控制器FD模块介绍

NVIDAI Jetson仅包含有CAN控制器:
Xavier：2xCAN
NX : 1xCAN
TX2 : 2xCAN
Nano：无CAN

NVIDIA Jetson 自带CAN孔子去需增加CAN收发器（市面上非常多型号）如:
Microchip - MCP2557FD/2558FD
TI - SN65HVD231DG4
NXP - TJA1043

Xavier MTTCAN控制器，相关详细的应用可参考：
https://elinux.org/Jetson/AGX_Xavier_CAN
CSDN NVIDIA Xavier CAN

NX MTTCAN控制器，相关详细的应用可参考：
How to using CAN In nx devkit

然而在很多场景下，Jetson 自带的CAN控制器是不够用的，此时就需要额外扩展CAN接口，常见的CAN扩展方式包括：PCIe\Ethernet\USB\SPI\UART等等

下面介绍的是SPI转CAN，型号包括：
Microchip MCP2515
Microchip MCP2518FD (2xCS信号，扩展2xCAN 接口)

首先是Seeed 的树莓派的CAN BUS FD Shield(MCP2518FD)在Jetson Nano、NX、Xavier上的应用，其中官方已经提供了Nano上的参考软件、硬件接口等
https://wiki.seeedstudio.com/2-Channel-CAN-BUS-FD-Shield-for-Raspberry-Pi/

Seeedstudio CAN Nano.png

Jetson Nano (官方验证）
步骤1、
git clone https://github.com/Seeed-Studio/seeed-linux-dtoverlays
步骤2、编译dtbo 和 driver
cd seeed-linux-dtoverlays
export CUSTOM_MOD_LIST="CAN-HAT"; make all_jetsonnano
步骤3、安装驱动
sudo -E make install_jetsonnano
步骤4、安装dtbo
sudo cp overlays/jetsonnano/2xMCP2518FD-spi0.dtbo /boot
sudo /opt/nvidia/jetson-io/config-by-hardware.py -n "Seeed 2xMCP2518FD"
步骤5、重启机器，查看can 设备及通讯验证

nano@jetson-nano:~$ dmesg | grep spi
[   10.867712] mcp25xxfd spi0.0 can0: MCP2518FD rev0.0 (-RX_INT -MAB_NO_WARN +CRC_REG +CRC_RX +CRC_TX +ECC -HD m:20.00MHz r:18.50MHz e:0.00MHz) successfully initialized.
[   10.879487] mcp25xxfd spi0.1 can1: MCP2518FD rev0.0 (-RX_INT -MAB_NO_WARN +CRC_REG +CRC_RX +CRC_TX +ECC -HD m:20.00MHz r:18.50MHz e:0.00MHz) successfully initialized.
 
nano@jetson-nano:~$ ifconfig -a
can0: flags=128<NOARP>  mtu 16
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 112
 
can1: flags=128<NOARP>  mtu 16
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 10  (UNSPEC)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 114

#短接CAN0-L和CAN1-L， CAN0-H和CAN1-H
#通过can0发送数据
cangen can0 -mv 

#通过can1接收数据
candump can1

Jetson NX
步骤1、
git clone https://github.com/Seeed-Studio/seeed-linux-dtoverlays
步骤2、修改dts、driver并编译dtbo 和 driver
cd seeed-linux-dtoverlays
export CUSTOM_MOD_LIST="CAN-HAT"; make all_jetsonnx
步骤3、安装驱动
sudo -E make install_jetsonnx
步骤4、安装dtbo
sudo cp overlays/jetsonnX/2xMCP2518FD-spi0.dtbo /boot
sudo /opt/nvidia/jetson-io/config-by-hardware.py -n "Seeed 2xMCP2518FD"

Jetson Xavier
步骤1、
git clone https://github.com/Seeed-Studio/seeed-linux-dtoverlays
步骤2、修改dts、driver并编译dtbo 和 driver
cd seeed-linux-dtoverlays
export CUSTOM_MOD_LIST="CAN-HAT"; make all_jetsonxavier
步骤3、安装驱动
sudo -E make install_all_jetsonxavier
步骤4、安装dtbo
sudo cp overlays/jetsonxavier/2xMCP2518FD-spi0.dtbo /boot
sudo /opt/nvidia/jetson-io/config-by-hardware.py -n "Seeed 2xMCP2518FD"
步骤5、重启机器，查看can 设备及通讯验证

nvidia@xavier:~$ dmesg | grep 'spi'
[    0.794158] iommu: Adding device 3210000.spi to group 11
[ 4589.923309] mcp25xxfd spi0.0 can0: mcp25xxfd_register_done: 0 
[ 4589.923329] mcp25xxfd spi0.0 can0: MCP2518FD rev0.0 (-RX_INT -MAB_NO_WARN +CRC_REG +CRC_RX +CRC_TX +ECC -HD c:40.00MHz m:20.00MHz r:18.50MHz e:0.00MHz) successfully initialized.
[ 4589.936317] mcp25xxfd spi0.1 can1: mcp25xxfd_register_done: 0 
[ 4589.936333] mcp25xxfd spi0.1 can1: MCP2518FD rev0.0 (-RX_INT -MAB_NO_WARN +CRC_REG +CRC_RX +CRC_TX +ECC -HD c:40.00MHz m:20.00MHz r:18.50MHz e:0.00MHz) successfully initialized.

xavier.png

candum vs. cansend .png

Socket CAN 编程

报文发送（仅发送，不接收）
nvidia@xavier:~/$ vi socket_can0_send.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>

int main()
{
    int s, nbytes;
    struct sockaddr_can addr;
    struct ifreq ifr;
    struct can_frame frame[2] = {{0}};

    s = socket(PF_CAN, SOCK_RAW, CAN_RAW);//创建套接字
    strcpy(ifr.ifr_name, "can0" );
    ioctl(s, SIOCGIFINDEX, &ifr); //指定 can0 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 can0 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);
    //生成两个报文
    frame[0].can_id = 0x11;
    frame[0].can_dlc = 1;
    frame[0].data[0] = 'Y';
    frame[1].can_id = 0x22;
    frame[1].can_dlc = 1;
    frame[1].data[0] = 'N';
    //循环发送两个报文
    while(1)
    {
        nbytes = write(s, &frame[0], sizeof(frame[0])); //发送 frame[0]
        if(nbytes != sizeof(frame[0]))
        {
            printf("Send Error frame[0]\n!");
            break; //发送错误，退出
        }
        sleep(1);
        nbytes = write(s, &frame[1], sizeof(frame[1])); //发送 frame[1]
        if(nbytes != sizeof(frame[0]))
        {
            printf("Send Error frame[1]\n!");
            break;
        }
        sleep(1);
    }
    close(s);
    return 0;
}


报文接收（仅接收，不发送）
nvidia@xavier:~/$ vi socket_can0_recv.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> 

int main() 
{


                
    
        
            
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