RT-Thread-RTT-STUDIO CAN总线通讯RT-Thread问答社区

RTT-STUDIO CAN总线通讯

发布于 2021-04-30 18:55:57 浏览：2696 订阅该版

**不啰嗦直接开整**
**1. 创建工程，点击 cubemx配置CAN总线**
**第一步**
![image.png](https://oss-club.rt-thread.org/uploads/20210430/ee33662b92fa50652cb874a25706e93a.png)
**第二步**
![image.png](https://oss-club.rt-thread.org/uploads/20210430/ba9ebe202ca138f5efebd77e5d95134b.png)

2. 点击RT-Thread Settings 选用CAN协议
**第一步**
![image.png](https://oss-club.rt-thread.org/uploads/20210430/d7bc3b280feba052e5fec0f5d37596c0.png)
**第二步  使不使能 硬件过滤器看自己需求，测试驱动时尽量先不用，正式通讯时在开启**
![image.png](https://oss-club.rt-thread.org/uploads/20210430/d2a86ede236bee76259dd17eb4b43d76.png)
3. board.h中添加 #define BSP_USING_CAN 和 #define BSP_USING_CAN1 （使用CAN1）
```
#define BSP_USING_CAN
#define BSP_USING_CAN1
```
![image.png](https://oss-club.rt-thread.org/uploads/20210430/40295f9e852be70b99643066b40fe72d.png)

到这里基本就可以用了，但是可能是的BUG，有时候不会自动生成drv_can.c和drv_can.h
RTT的GitHub仓库，下载对应版本的库，我的是4.0.3版本
地址：https://github.com/RT-Thread/rt-thread/releases
![image.png](https://oss-club.rt-thread.org/uploads/20210430/0e43fa130233494ae08aa4618c6d98ba.png)
到对应目录
```
rt-thread-4.0.3\bsp\stm32\libraries\HAL_Drivers
```
找到对应文件
![image.png](https://oss-club.rt-thread.org/uploads/20210430/cdb44ea28dba57bf274e4a033d78fab1.png)

**4. 直接上驱动代码 ** 
[参考官方教程](https://www.rt-thread.org/document/site/programming-manual/device/can/can/#can_8)
```
/*
 * 程序清单：这是一个 CAN 设备使用例程
 * 例程导出了 can_sample 命令到控制终端
 * 命令调用格式：can_sample can1
 * 命令解释：命令第二个参数是要使用的 CAN 设备名称，为空则使用默认的 CAN 设备
 * 程序功能：通过 CAN 设备发送一帧，并创建一个线程接收数据然后打印输出。
*/

#include <rtthread.h>
#include "rtdevice.h"

#define CAN_DEV_NAME       "can1"      /* CAN 设备名称 */

static struct rt_semaphore rx_sem;     /* 用于接收消息的信号量 */
static rt_device_t can_dev;            /* CAN 设备句柄 */

/* 接收数据回调函数 */
static rt_err_t can_rx_call(rt_device_t dev, rt_size_t size)
{
    /* CAN 接收到数据后产生中断，调用此回调函数，然后发送接收信号量 */
    rt_sem_release(&rx_sem);

return RT_EOK;
}

static void can_rx_thread(void *parameter)
{
    int i;
    rt_err_t res;
    struct rt_can_msg rxmsg = {0};

/* 设置接收回调函数 */
    rt_device_set_rx_indicate(can_dev, can_rx_call);

#ifdef RT_CAN_USING_HDR
    struct rt_can_filter_item items[5] =
    {
        RT_CAN_FILTER_ITEM_INIT(0x100, 0, 0, 1, 0x700, RT_NULL, RT_NULL), /* std,match ID:0x100~0x1ff，hdr 为 - 1，设置默认过滤表 */
        RT_CAN_FILTER_ITEM_INIT(0x300, 0, 0, 1, 0x700, RT_NULL, RT_NULL), /* std,match ID:0x300~0x3ff，hdr 为 - 1 */
        RT_CAN_FILTER_ITEM_INIT(0x211, 0, 0, 1, 0x7ff, RT_NULL, RT_NULL), /* std,match ID:0x211，hdr 为 - 1 */
        RT_CAN_FILTER_STD_INIT(0x486, RT_NULL, RT_NULL),                  /* std,match ID:0x486，hdr 为 - 1 */
        {0x555, 0, 0, 1, 0x7ff, 7,}                                       /* std,match ID:0x555，hdr 为 7，指定设置 7 号过滤表 */
    };
    struct rt_can_filter_config cfg = {5, 1, items}; /* 一共有 5 个过滤表 */
    /* 设置硬件过滤表 */
    res = rt_device_control(can_dev, RT_CAN_CMD_SET_FILTER, &cfg);
    RT_ASSERT(res == RT_EOK);
#endif

while (1)
    {
        /* hdr 值为 - 1，表示直接从 uselist 链表读取数据 */
        rxmsg.hdr = -1;
        /* 阻塞等待接收信号量 */
        rt_sem_take(&rx_sem, RT_WAITING_FOREVER);
        /* 从 CAN 读取一帧数据 */
        rt_device_read(can_dev, 0, &rxmsg, sizeof(rxmsg));
        /* 打印数据 ID 及内容 */
        rt_kprintf("ID:%x", rxmsg.id);
        for (i = 0; i < 8; i++)
        {
            rt_kprintf("%2x", rxmsg.data[i]);
        }

rt_kprintf("\n");
    }
}

int can_sample(int argc, char *argv[])
{
    struct rt_can_msg msg = {0};
    rt_err_t res;
    rt_size_t  size;
    rt_thread_t thread;
    char can_name[RT_NAME_MAX];

if (argc == 2)
    {
        rt_strncpy(can_name, argv[1], RT_NAME_MAX);
    }
    else
    {
        rt_strncpy(can_name, CAN_DEV_NAME, RT_NAME_MAX);
    }
    /* 查找 CAN 设备 */
    can_dev = rt_device_find(can_name);
    if (!can_dev)
    {
        rt_kprintf("find %s failed!\n", can_name);
        return RT_ERROR;
    }

/* 初始化 CAN 接收信号量 */
    rt_sem_init(&rx_sem, "rx_sem", 0, RT_IPC_FLAG_FIFO);

/* 以中断接收及发送方式打开 CAN 设备 */
    res = rt_device_open(can_dev, RT_DEVICE_FLAG_INT_TX | RT_DEVICE_FLAG_INT_RX);
    RT_ASSERT(res == RT_EOK);
    /* 创建数据接收线程 */
    thread = rt_thread_create("can_rx", can_rx_thread, RT_NULL, 1024, 25, 10);
    if (thread != RT_NULL)
    {
        rt_thread_startup(thread);
    }
    else
    {
        rt_kprintf("create can_rx thread failed!\n");
    }

msg.id = 0x78;              /* ID 为 0x78 */
    msg.ide = RT_CAN_STDID;     /* 标准格式 */
    msg.rtr = RT_CAN_DTR;       /* 数据帧 */
    msg.len = 8;                /* 数据长度为 8 */
    /* 待发送的 8 字节数据 */
    msg.data[0] = 0x00;
    msg.data[1] = 0x11;
    msg.data[2] = 0x22;
    msg.data[3] = 0x33;
    msg.data[4] = 0x44;
    msg.data[5] = 0x55;
    msg.data[6] = 0x66;
    msg.data[7] = 0x77;
    /* 发送一帧 CAN 数据 */
    size = rt_device_write(can_dev, 0, &msg, sizeof(msg));
    if (size == 0)
    {
        rt_kprintf("can dev write data failed!\n");
    }

return res;
}
/* 导出到 msh 命令列表中 */
MSH_CMD_EXPORT(can_sample, can device sample);
```

**5. 你可能出错了**
- 没有对应板子型号的CAN分频表，自己添加，如下图，参数怎么定，看下STM32如何计算CAN波特率
![image.png](https://oss-club.rt-thread.org/uploads/20210430/2a5289cf9d44761346b4363e0ab64532.png)
**6. 你可能又出错了**
检查下自己有没有节其他设备，至少还有另一个节点才能正常。
**7. 你还有问题？**
看下其他相关论坛文章吧