RT-Thread-N32L40XCL-STB 开发板模块评测任务大挑战之测试CANRT-Thread问答社区

N32L40XCL-STB 开发板模块评测任务大挑战之测试CAN

发布于 2023-04-19 18:47:56 浏览：473 订阅该版

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# 软件准备
https://club.rt-thread.org/ask/article/5fa29a88d58b5790.html

在这篇文章的基础上，在applicantions文件夹下新建test_can.c，内容如下：

```c
/*
 * 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 bxcna
 * 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 "can_dewen.h"
#include <rtthread.h>
#include "rtdevice.h"

#define CAN_DEV_NAME       "bxcan"      /* 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;
}

int can_send(rt_uint32_t humi,rt_uint32_t temp)
{
    struct rt_can_msg msg = {0};
    rt_err_t res;
    rt_size_t  size;
    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] = (uint8_t)(temp/100);
       msg.data[1] = (uint8_t)(temp%100);
       msg.data[2] = (uint8_t)(humi/100);
       msg.data[3] = (uint8_t)(humi%100);
       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;
}

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, 0, 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, 0, 0x700, RT_NULL, RT_NULL), /* std,match ID:0x300~0x3ff，hdr 为 - 1 */
        RT_CAN_FILTER_ITEM_INIT(0x211, 0, 0, 0, 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, 0, 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(void)
{
    struct rt_can_msg msg = {0};
    rt_err_t res;
    rt_size_t  size;
    rt_thread_t thread;
    char can_name[RT_NAME_MAX];

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);
    /* 设置 CAN 通信的波特率为 500kbit/s*/
    res = rt_device_control(can_dev, RT_CAN_CMD_SET_BAUD, (void *)CAN500kBaud);
    /* 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);

```
然后编译下载到开发板。

# 硬件准备
1. CAN分析仪
2. CAN——TTL模块

# 调试步骤
- 硬件接好  TTL——CAN TX ————开发板PB9，TTL——CAN RX————开发板PB8
- 通过集线器把CAN分析仪CAN——H 与TTL的CAN——H 相接 CAN——L与CAN——L接好。
- 通过串品终端执行can_sample:

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230419/54d63d0243aa687e3aec246beb7dcbeb.png)
- 打开CAN分析仪上位机,自动OBD识别，识别到了500K的CAN总，同时也接收到了开发板发送的认证数据。发送数据，在开发板的串口终端也成功接收并打印出来：

![screenshot_image.png](https://oss-club.rt-thread.org/uploads/20230419/76eba0ffc31df29494331c2d42edbb8f.png.webp)
【总结】
国民技术在RT-Thread上的生态非常好，可以快速的实现对外设的驱动。