rt_thread中如何使用CAN硬件过滤器？

发布于 2023-07-31 19:20:24 浏览：821 订阅该版

目前我使用rt_thread版本为v4.1.1,目前使用了两路can，想要对两路can的数据进行硬件过滤处理，降低CPU负荷。
过滤的ID为:

```c
    #define STEER_STA_FEEDBACK_MSG_ID 0x203
    #define BRAKE_STA_FEEDBACK_MSG_ID 0x202
    #define DRIVE_STA_FEEDBACK_MSG_ID 0x201
    #define BMS_STA_FEEDBACK_MSG_ID 0x1884EFF3
    #define MCU_STA_FEEDBACK_MSG_ID 0x0C0221E
    #define WHEEL_ROTATE_FEEDBACK_MSG_ID 0x18FEF115
```
初始化代码如下：

```c
#ifdef RT_CAN_USING_HDR
    CanDevRecFilterCfg can1_dev_filter;
    CanDevRecFilterCfg can2_dev_filter;
#endif
#ifdef RT_CAN_USING_HDR
    CanDevRecFilterCfg * GetFilterCfgPtr(CanCfgEnum _type)
    {
        CanDevRecFilterCfg * _cfg = RT_NULL;
        switch (_type)
        {
            case CAN1_DEV_CFG:
                _cfg = &can1_dev_filter;
                break;
            case CAN2_DEV_CFG:
                #ifndef APP_USING_CAN2_DEV
                    LOG_E("Pls config switch the app using can2 dev");
                    break;
                #endif
                _cfg = &can2_dev_filter;
                break;    
            default:
                break;
        }
        return _cfg;
    }
    /**
     * @brief Set the Can Dev I D Filter object
     * @param  _type     CAN设备索引
     * @param  match_id  需要过滤的ID
     * @return rt_err_t RT_EOK 成功 -RT_ERROR失败
     */
    rt_err_t SetCanDevIDFilter(CanCfgEnum _type,rt_uint32_t match_id)
    {
        struct rt_can_filter_item _temp_filter = RT_CAN_FILTER_EXT_INIT(match_id,RT_NULL, RT_NULL);
        struct can_app_struct *_can_dev_cfg = RT_NULL;
        CanDevRecFilterCfg * _cfg = GetFilterCfgPtr(_type);
        RT_ASSERT(_cfg != RT_NULL);
        if((_cfg->used_filter_num+1) > 27)
        {
            LOG_E("Beyond the max filter num!!");
            return RT_ERROR;
        }
        if(match_id > 0x7FF)
        {
            //过滤的是扩展帧
            _temp_filter.ide = 1;
             _cfg->filter[_cfg->used_filter_num] = _temp_filter;
        }
        else
        {
            _temp_filter.ide = 0;
            _cfg->filter[_cfg->used_filter_num] = _temp_filter;
        }
        //执行配置操作
        _cfg->filter_cfg.items =   _cfg->filter;
        _cfg->filter_cfg.count = _cfg->used_filter_num+1;
        _cfg->filter_cfg.actived = 1;
        //更新配置
        _can_dev_cfg = GetCanCfg(_type);
        RT_ASSERT(_cfg != RT_NULL);
        if(rt_device_control(_can_dev_cfg->dev, RT_CAN_CMD_SET_FILTER, &_cfg->filter_cfg) != RT_EOK)
        {
            return -RT_ERROR;
        }
        _cfg->used_filter_num++;
        return RT_EOK;
    }
#endif
```
我分别对can1 和can2进行了3组hdr配置,最终的表现结果为在接收部分只能收到ID为0x18FEF115或者ID为0x0C0221E的数据，其余的都收不到。
我这样的需求应该怎么样配置HDR才能正确进行接收呢？我使用官网的例程也存在这个问题。

1 个回答

yangbo18416 2023-08-01

这家伙很懒，什么也没写！

问题已经得到解决了。在4.1.1的drv_can.c的339行处，代码有问题

```c
if (filter_cfg->items[i].hdr == -1)
                {
                    /* use default filter bank settings */
                    if (drv_can->name == "can1")
                    {
                        /* can1 banks 0~13 */
                        drv_can->FilterConfig.FilterBank = i;
                    }
                    else if (drv_can->name == "can2")
                    {
                        /* can1 banks 14~27 */
                        drv_can->FilterConfig.FilterBank = i + 14;
                    }
                }
                else
                {
                    /* use user-defined filter bank settings */
                    drv_can->FilterConfig.FilterBank = filter_cfg->items[i].hdr;
                }
```
将这个部分修改为

```c
if (filter_cfg->items[i].hdr == -1)
                {
                    /* use default filter bank settings */
                    if(rt_memcmp(drv_can->name,"can1",sizeof("can1")) == 0)
                    {
                        /* can1 banks 0~13 */
                        drv_can->FilterConfig.FilterBank = i;
                    }
                    else if(rt_memcmp(drv_can->name,"can2",sizeof("can2")) == 0)
                    {
                        /* can1 banks 14~27 */
                        drv_can->FilterConfig.FilterBank = i + 14;
                    }
                }
                else
                {
                    /* use user-defined filter bank settings */
                    drv_can->FilterConfig.FilterBank = filter_cfg->items[i].hdr;
                }
```
就可以了。
最新版中已经修改了这个问题了