stm32之can总线过滤器研究

stm32的can总线的配置如下：

can_initstructure.can_ttcm=disable;//禁止时间触发通信模式

can_initstructure.can_abom=disable;

can_initstructure.can_awum=disable;

can_initstructure.can_nart=disable;//can报文只被发送1次，不管发送的结果如何（成功、出错或仲裁丢失） 

can_initstructure.can_rflm=disable;

can_initstructure.can_txfp=disable;

can_initstructure.can_mode=can_mode_normal;

//can_mode_loopback

//can_mode_normal

can_initstructure.can_sjw=can_sjw_1tq;

can_initstructure.can_bs1=can_bs1_5tq;//1--16

can_initstructure.can_bs2=can_bs2_2tq;//1--8

can_initstructure.can_prescaler=2;

      can_init(&can_initstructure);

       /* can filter init

*/

can_filterinitstructure.can_filternumber=0;//选择过滤器0

can_filterinitstructure.can_filtermode=can_filtermode_idmask;//指定过滤器被设置为标识符屏蔽模式

can_filterinitstructure.can_filterscale=can_filterscale_32bit;//给出过滤器位宽为32位

下面根据设置的参数不同来决定can总线can总线的配置情况：

1、对扩展数据帧进行过滤:(只接收扩展数据帧)

can_filterinitstructure.can_filteridhigh   =

(((u32)slave_id<<3)&0xffff0000)>>16;

can_filterinitstructure.can_filteridlow   =

(((u32)slave_id<<3)|can_id_ext|can_rtr_data)&0xffff;

can_filterinitstructure.can_filtermaskidhigh  =

0xffff;

can_filterinitstructure.can_filtermaskidlow   =

(注：标准帧数据帧、标准远程帧和扩展远程帧均被过滤)

2、对扩展远程帧过滤:(只接收扩展远程帧)

(((u32)slave_id<<3)|can_id_ext|can_rtr_remote)&0xffff;

can_filterinitstructure.can_filtermaskidlow   = 0xffff;

3、对标准远程帧过滤:(只接收标准远程帧)

(((u32)slave_id<<21)&0xffff0000)>>16;

(((u32)slave_id<<21)|can_id_std|can_rtr_remote)&0xffff;

4、对标准数据帧过滤:(只接收标准数据帧)

(((u32)slave_id<<21)|can_id_std|can_rtr_data)&0xffff;

5、对扩展帧进行过滤:(扩展帧不会被过滤掉)

(((u32)slave_id<<3)|can_id_ext)&0xffff;

can_filterinitstructure.can_filtermaskidlow   = 0xfffc;

6、对标准帧进行过滤:(标准帧不会被过滤掉)

(((u32)slave_id<<21)|can_id_std)&0xffff;

注：slave_id为要过滤的id号。