在调试KF32A156的CANFD功能，需要使用硬过滤来降低软件负荷，在配置CANFD全局掩码和MBx_MASK(邮箱专用掩码)时配到了一些小问题，特记录下来。
先来看看KF32A156用户手册中对CANFD全局掩码和邮箱专用掩码的描述：
以上描述说明了全局掩码和邮箱专用掩码共同决定着过滤的结果，因此参照官方例程，详细配置如下：
const uint32_t CAN_ID[51] = {
0x00,0x00,0x120,0x121,0x122,0x123,0x124,0x125,0x126,0x127,
0x128,0x129,0x130,0x131,0x132,0x133,0x134,0x135,0x136,0x137,
0x138,0x139,0x4F0,0x4F1,0x4F2,0x4F3,0x4F4,0x4F5,0x4F6,0x4F7,
0x4F8,0x4F9,0x500,0x00,0x00,0x00,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00
};/*** @brief :Receive Mailbox init* @param in :Can_Controller_Index* @param out :None* @retval :None*/
void Receive_Mailboxinit(const uint8_t Can_Controller_Index) {volatile uint8_t retryTimes;Canfd_ReturnType ret;uint8_t receviemailbox = 0x00;for (receviemailbox = 2; receviemailbox <= 35; receviemailbox++) {Can_Receive_Mailbox_BUFFER[0].Id = CAN_ID[receviemailbox];Can_Receive_Mailbox_BUFFER[0].Can_id = CAN_DATA_STANDARD;Can_Receive_Mailbox_BUFFER[0].TransceiveType = MAIL_RECEIVE;do{ret = Can_m_FdMailBox_Write(Can_Controller_Index, receviemailbox,&Can_Receive_Mailbox_BUFFER[0]);} while ((CAN_OK != ret) && ((retryTimes++) < CAN_RETRY_TIMES));}
}#if (HARDWARE_FILTER == STD_ON)
Can_HwFilterType Can_HwFilter = {/* Filter 0 */0x00000000U, /* Mask code *//* Filter 1 */0x00000000U, /* Mask code *//* Filter 2 */0x00000000U, /* Mask code *//* Filter 3 */0x00000000U, /* Mask code *//* Filter 4 */0x00000000U, /* Mask code *//* Filter 5 */0x00000000U, /* Mask code *//* Filter 6 */0x00000000U, /* Mask code *//* Filter 7 */0x00000000U, /* Mask code *//* Filter 8 */0x00000000U, /* Mask code *//* Filter 9 */0x00000000U, /* Mask code *//* Filter 10 */0x00000000U, /* Mask code *//* Filter 11 */0x00000000U, /* Mask code *//* Filter 12 */0x00000000U, /* Mask code *//* Filter 13 */0x00000000U, /* Mask code *//* Filter 14 */0x00000000U, /* Mask code *//* Filter 15 */0x00000000U, /* Mask code *//* Filter 16 */0x00000000U, /* Mask code *//* Filter 17 */0x00000000U, /* Mask code *//* Filter 18 */0x00000000U, /* Mask code *//* Filter 19 */0x00000000U, /* Mask code *//* Filter 20 */0x00000000U, /* Mask code *//* Filter 21 */0x00000000U, /* Mask code *//* Filter 22 */0x00000000U, /* Mask code *//* Filter 23 */0x00000000U, /* Mask code *//* Filter 24 */0x00000000U, /* Mask code *//* Filter 25 */0x00000000U, /* Mask code *//* Filter 26 */0x00000000U, /* Mask code *//* Filter 27 */0x00000000U, /* Mask code *//* Filter 28 */0x00000000U, /* Mask code *//* Filter 29 */0x00000000U, /* Mask code *//* Filter 30 */0x00000000U, /* Mask code *//* Filter 31 */0x00000000U, /* Mask code *//* Filter 32 */0x1FFFFFF8U, /* Mask code *//* Filter 33 */0x00000000U, /* Mask code *//* Filter 34 */0x00000000U, /* Mask code *//* Filter 35 */0x00000000U, /* Mask code *//* Filter 36 */0x00000000U, /* Mask code *//* Filter 37 */0x00000000U, /* Mask code *//* Filter 38 */0x00000000U, /* Mask code *//* Filter 39 */0x00000000U, /* Mask code *//* Filter 40 */0x00000000U, /* Mask code *//* Filter 41 */0x00000000U, /* Mask code *//* Filter 42 */0x00000000U, /* Mask code *//* Filter 43 */0x00000000U, /* Mask code *//* Filter 44 */0x00000000U, /* Mask code *//* Filter 45 */0x00000000U, /* Mask code *//* Filter 46 */0x00000000U, /* Mask code *//* Filter 47 */0x00000000U, /* Mask code *//* Filter 48 */0x00000000U, /* Mask code *//* Filter 49 */0x00000000U, /* Mask code *//* Filter 50 */0x00000000U, /* Mask code *//* Filter 0 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 1 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 2 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 3 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 4 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 5 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 6 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 7 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 8 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 9 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 10 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 11 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 12 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 13 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 14 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 15 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 16 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 17 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 18 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 19 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 20 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 21 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 22 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 23 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 24 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 25 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 26 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 27 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 28 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 29 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 30 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 31 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 32 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 33 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 34 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 35 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 36 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 37 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 38 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 39 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 40 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 41 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 42 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 43 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 44 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 45 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 46 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 47 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 48 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 49 */CAN_FILTER_STANDARD, /* Acceptance code type *//* Filter 50 */CAN_FILTER_STANDARD, /* Acceptance code type */};
#endifCanfd_ConfigType Canfd_Controller_AllConfig[1] = {/* Can 0 Config */{/* Can controller Mode setValue Range :CANFD_NORMAL_MODECANFD_LOOP_INTERNAL_MODECANFD_LOOP_EXTERNAL_MODECANFD_SILENT_MODE */CANFD_NORMAL_MODE,/* Can FD Mode setValue Range :DISABLEENABLE */ENABLE,
/* Can controller clock source setValue Range :CAN_CLOCKSOURCE_SCLKCAN_CLOCKSOURCE_HFCLKCAN_CLOCKSOURCE_LFCLK */
#if (WORKSOURCE_HFCLK == STD_ON)CAN_CLOCKSOURCE_HFCLK,
#elseCAN_CLOCKSOURCE_SCLK,
#endif/* Can controller Arbitrate clock source setValue Range :CAN_CLOCKSOURCE_SCLKCAN_CLOCKSOURCE_HFCLKCAN_CLOCKSOURCE_LFCLK */CAN_CLOCKSOURCE_SCLK,/* Mailbox block size configValue Range :CAN_8_BYTE_DATALENGTH :CAN_16_BYTE_DATALENGTH :CAN_32_BYTE_DATALENGTH :CAN_64_BYTE_DATALENGTH : */CAN_8_BYTE_DATALENGTH,/* Iso mode or non-iso mode configValue Range :CAN_FD_NON_ISOMODE :CAN_FD_ISOMODE : */CAN_FD_ISOMODE,
/* Global Mask Set */
#if (HARDWARE_FILTER == STD_ON)0x00000000,
#else0xFFFFFFFF,
#endif/* Enable/disable mailbox full receive config
Value Range :CAN_MBFULLRECEIVE_DISABLECAN_MBFULLRECEIVE_ENABLE */CAN_MBFULLRECEIVE_DISABLE,/* Interrupt config */&Can_Controller_InterruptConfig[0],
#if (HARDWARE_FILTER == STD_ON)/* Hardware Filter config */&Can_HwFilter,
#endif/* Arbitrate Segment Baudrate Config */&Canfd_Controller_AllClockAndBDRConfig[0],/* Data Segment Baudrate Config */&Canfd_Controller_ALLFdBDRConfig[0],},/* end */
};自测发现，发送0x501,无法触发CANFD接收中断，修改报文ID为0x500,可以触发CANFD接收中断，说明ID是0x501报文被过滤掉了;在线调试时发现，查看初始化的代码发现如下函数中,当MBIndex是32时，MaskValue的值是0x1ffffff8,而fdMask.SFF.MASK的是0x7F8；
查看FdMask_Type的定义如下：
/* ------------------------------------------------------------------------------ 增强型控制器局域网总线（CANFD）---------------------------------------------------------------------------- */
typedef union
{volatile uint32_t MaskCode;union{struct{uint32_t :21;volatile uint32_t MASK :11;} SFF;struct{uint32_t :3;volatile uint32_t MASK :29;} EFF;};
} FdMask_Type;可以看出是低11位保存到了fdMask.SFF.MASK中(大小端的问题)，修改如下进行验证是不是这个问题：
/* Filter 32 */0x1FFFFF5AU, /* Mask code */验证如下：
确定是这个问题后，做如下修改：
/* Filter 32 */0xFFFFF8FFU, /* Mask code */ // 接收0x5xx的报文经验证，终于实现了功能(能正常接收0x500~0x5FF的报文)。
