在调试28335的CAN的发送时出现的问题：

1、接口用错导致一直失败；

2、注意28335的CAN总线波特率计算，如下所述：

ECanaShadow.CANBTC.bit.BRPREG = 9;

ECanaShadow.CANBTC.bit.TSEG2REG = 2;

ECanaShadow.CANBTC.bit.TSEG1REG = 10;

以上代码是配置28335的CAN总线模块波特率，最后的波特率为：

讯享网

按照上面的参数计算最后的波特率为500k;

同时还需要注意28335的CAN总线中比较特殊的说明,如下所述：

1、是关于波特率配置的描述：

2、关于CAN网络的说明：

必须保证在网络中有一个设备和当前节点配置为同样的波特率，但是不一定要设置为接收模式；

附：最后的配置程序：

void InitECana(void) // 初始化CAN总线模块 { /* Create a shadow register structure for the CAN control registers. This is needed, since only 32-bit access is allowed to these registers. 16-bit access to these registers could potentially corrupt the register contents or return false data. This is especially true while writing to/reading from a bit (or group of bits) among bits 16 - 31 */ struct ECAN_REGS ECanaShadow; EALLOW; // EALLOW enables access to protected bits /* Configure eCAN RX and TX pins for CAN operation using eCAN regs*/ ECanaShadow.CANTIOC.all = ECanaRegs.CANTIOC.all; ECanaShadow.CANTIOC.bit.TXFUNC = 1; ECanaRegs.CANTIOC.all = ECanaShadow.CANTIOC.all; ECanaShadow.CANRIOC.all = ECanaRegs.CANRIOC.all; ECanaShadow.CANRIOC.bit.RXFUNC = 1; ECanaRegs.CANRIOC.all = ECanaShadow.CANRIOC.all; /* Configure eCAN for HECC mode - (reqd to access mailboxes 16 thru 31) */ // HECC mode also enables time-stamping feature ECanaShadow.CANMC.all = ECanaRegs.CANMC.all; ECanaShadow.CANMC.bit.SCB = 1; ECanaRegs.CANMC.all = ECanaShadow.CANMC.all; /* Initialize all bits of 'Master Control Field' to zero */ // Some bits of MSGCTRL register come up in an unknown state. For proper operation, // all bits (including reserved bits) of MSGCTRL must be initialized to zero ECanaMboxes.MBOX0.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX1.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX2.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX3.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX4.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX5.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX6.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX7.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX8.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX9.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX10.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX11.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX12.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX13.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX14.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX15.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX16.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX17.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX18.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX19.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX20.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX21.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX22.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX23.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX24.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX25.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX26.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX27.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX28.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX29.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX30.MSGCTRL.all = 0x00000000; ECanaMboxes.MBOX31.MSGCTRL.all = 0x00000000; // TAn, RMPn, GIFn bits are all zero upon reset and are cleared again // as a matter of precaution. ECanaRegs.CANTA.all = 0xFFFFFFFF; /* Clear all TAn bits */ ECanaRegs.CANRMP.all = 0xFFFFFFFF; /* Clear all RMPn bits */ ECanaRegs.CANGIF0.all = 0xFFFFFFFF; /* Clear all interrupt flag bits */ ECanaRegs.CANGIF1.all = 0xFFFFFFFF; /* Configure bit timing parameters for eCANA*/ ECanaShadow.CANMC.all = ECanaRegs.CANMC.all; ECanaShadow.CANMC.bit.CCR = 1 ; // Set CCR = 1 ECanaRegs.CANMC.all = ECanaShadow.CANMC.all; ECanaShadow.CANES.all = ECanaRegs.CANES.all; do { ECanaShadow.CANES.all = ECanaRegs.CANES.all; } while(ECanaShadow.CANES.bit.CCE != 1 ); // Wait for CCE bit to be set.. ECanaShadow.CANBTC.all = 0; #if (CPU_FRQ_150MHZ) //初始化通信波特率 /* 具体的波特率计算： 波特率=系统时钟/(2*(BRPREG+TSEG2REG+TSEG1REG+3)),同时需要确保TSEG1REG > TSEG2REG */ ECanaShadow.CANBTC.bit.BRPREG = 9; ECanaShadow.CANBTC.bit.TSEG2REG = 2; ECanaShadow.CANBTC.bit.TSEG1REG = 10; #endif ECanaShadow.CANBTC.bit.SAM = 1; ECanaRegs.CANBTC.all = ECanaShadow.CANBTC.all; ECanaShadow.CANMC.all = ECanaRegs.CANMC.all; ECanaShadow.CANMC.bit.CCR = 0 ; // Set CCR = 0 ECanaRegs.CANMC.all = ECanaShadow.CANMC.all; ECanaShadow.CANES.all = ECanaRegs.CANES.all; do { ECanaShadow.CANES.all = ECanaRegs.CANES.all; } while(ECanaShadow.CANES.bit.CCE != 0 ); // Wait for CCE bit to be cleared.. /* Disable all Mailboxes */ ECanaRegs.CANME.all = 0; // Required before writing the MSGIDs EDIS; } void InitECanGpio(void) { InitECanaGpio(); #if (DSP28_ECANB) InitECanbGpio(); #endif // if DSP28_ECANB } void InitECanaGpio(void) { EALLOW; /* Enable internal pull-up for the selected CAN pins */ // Pull-ups can be enabled or disabled by the user. // This will enable the pullups for the specified pins. // Comment out other unwanted lines. GpioCtrlRegs.GPAPUD.bit.GPIO18 = 0; // Enable pull-up for GPIO18 (CANRXA) GpioCtrlRegs.GPAPUD.bit.GPIO19 = 0; // Enable pull-up for GPIO19 (CANTXA) /* Set qualification for selected CAN pins to asynch only */ // Inputs are synchronized to SYSCLKOUT by default. // This will select asynch (no qualification) for the selected pins. GpioCtrlRegs.GPAQSEL2.bit.GPIO18 = 3; // Asynch qual for GPIO18 (CANRXA) /* Configure eCAN-A pins using GPIO regs*/ // This specifies which of the possible GPIO pins will be eCAN functional pins. GpioCtrlRegs.GPAMUX2.bit.GPIO18 = 3; // Configure GPIO18 for CANRXA operation GpioCtrlRegs.GPAMUX2.bit.GPIO19 = 3; // Configure GPIO19 for CANTXA operation EDIS; } #if (DSP28_ECANB) void InitECanbGpio(void) { EALLOW; /* Enable internal pull-up for the selected CAN pins */ // Pull-ups can be enabled or disabled by the user. // This will enable the pullups for the specified pins. // Comment out other unwanted lines. GpioCtrlRegs.GPAPUD.bit.GPIO12 = 0; // Enable pull-up for GPIO12 (CANTXB) GpioCtrlRegs.GPAPUD.bit.GPIO13 = 0; // Enable pull-up for GPIO13 (CANRXB) /* Set qualification for selected CAN pins to asynch only */ // Inputs are synchronized to SYSCLKOUT by default. // This will select asynch (no qualification) for the selected pins. // Comment out other unwanted lines. GpioCtrlRegs.GPAQSEL1.bit.GPIO13 = 3; // Asynch qual for GPIO13 (CANRXB) /* Configure eCAN-B pins using GPIO regs*/ GpioCtrlRegs.GPAMUX1.bit.GPIO12 = 2; // Configure GPIO12 for CANTXB operation GpioCtrlRegs.GPAMUX1.bit.GPIO13 = 2; // Configure GPIO13 for CANRXB operation EDIS; } #endif // if DSP28_ECANB 

具体关于CAN总线中的收发问题：

1、发送

.具体描述参见上图，配置程序如下所示：

讯享网//发送一帧数据 /* CAN总线发送数据结构体 typedef struct {       unsigned short int StdId;  //标准帧ID,值为0x000到0x7FFF;       unsigned long int ExtId; //扩展帧ID,值为0到0x1FFFFFFF       unsigned char SAE_J1939_Flag;//表示是否使用SAE J1939协议       SAE_ID SAE_J1939_ID;       unsigned char IDE;   //帧类型,可为：CAN_ID_STD(标准帧),CAN_ID_EXT(扩展帧)       unsigned char DLC;  //数据长度，可为0到8;       unsigned char MBox_num;//邮箱编号,可为0到31;       unsigned short int Tx_timeout_cnt;       CAN_MSG_DATA CAN_Tx_msg_data; /*!< 帧消息内容,共8字节 */ } CanTxMsg; */ void CAN_Send_Msg(CanTxMsg *can_tx_msg)//发送一帧数据 { Uint16 time_cnt; Uint32 mbox_enable_temp = 0x0000; Uint32 mbox_disable_temp = 0x0000; Uint32 mbox_dir_temp = 0x0000; mbox_enable_temp = 1<<(can_tx_msg->MBox_num); mbox_disable_temp = ~(1<<(can_tx_msg->MBox_num)); mbox_dir_temp = ~(1<<(can_tx_msg->MBox_num)); struct ECAN_REGS ECanaShadow; volatile struct MBOX *Mailbox; Mailbox = &ECanaMboxes.MBOX0+can_tx_msg->MBox_num; ECanaShadow.CANME.all = ECanaRegs.CANME.all; ECanaShadow.CANME.all &= mbox_disable_temp; ECanaRegs.CANME.all = ECanaShadow.CANME.all; if(can_tx_msg->IDE == CAN_ID_STD) { Mailbox->MSGID.all = can_tx_msg->StdId; //standard identifier Mailbox->MSGID.bit.IDE = can_tx_msg->IDE; } else if(can_tx_msg->IDE == CAN_ID_EXT) { if(can_tx_msg->SAE_J1939_Flag == 0) { Mailbox->MSGID.all = can_tx_msg->ExtId; //extended identifier. Mailbox->MSGID.bit.IDE = can_tx_msg->IDE; } else { Mailbox->MSGID.all = can_tx_msg->SAE_J1939_ID.id; //extended identifier. Mailbox->MSGID.bit.IDE = can_tx_msg->IDE; } } ECanaShadow.CANMD.all = ECanaRegs.CANMD.all; ECanaShadow.CANMD.all &=mbox_dir_temp;//设置邮箱工作方向,0表示邮箱工作于发送,1表示工作于接收 ECanaRegs.CANMD.all = ECanaShadow.CANMD.all; ECanaShadow.CANME.all = ECanaRegs.CANME.all; ECanaShadow.CANME.all |= mbox_enable_temp;//使能邮箱 ECanaRegs.CANME.all = ECanaShadow.CANME.all; Mailbox->MSGCTRL.bit.DLC = can_tx_msg->DLC;//数据长度 Mailbox->MDL.byte.BYTE0 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte0; Mailbox->MDL.byte.BYTE1 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte1; Mailbox->MDL.byte.BYTE2 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte2; Mailbox->MDL.byte.BYTE3 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte3; Mailbox->MDH.byte.BYTE4 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte4; Mailbox->MDH.byte.BYTE5 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte5; Mailbox->MDH.byte.BYTE6 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte6; Mailbox->MDH.byte.BYTE7 = can_tx_msg->CAN_Tx_msg_data.msg_Byte.byte7; ECanaShadow.CANTRS.all = 0; ECanaShadow.CANTRS.all |= mbox_enable_temp; // Set TRS for mailbox under test ECanaRegs.CANTRS.all = ECanaShadow.CANTRS.all; do { ECanaShadow.CANTA.all = ECanaRegs.CANTA.all; time_cnt++; } while(((ECanaShadow.CANTA.all&mbox_enable_temp) == 0 )&&(time_cnt<100)); // Wait for TA5 bit to be set.. ECanaShadow.CANTA.all = 0; ECanaShadow.CANTA.all = mbox_enable_temp; // Clear TA5 ECanaRegs.CANTA.all = ECanaShadow.CANTA.all; } 

 接收相关配置：（数据接受通常会采用中断来接收数据),具体配置程序如下，包括中断的相关配置；

void CAN_Rx_Config(void)//接收配置函数，程序中相关备注 { struct ECAN_REGS ECanaShadow; ECanaShadow.CANME.all = ECanaRegs.CANME.all; ECanaShadow.CANME.bit.ME1 = 0;//不使能邮箱1 ECanaShadow.CANME.bit.ME31 = 0;//不使能邮箱31 ECanaRegs.CANME.all = ECanaShadow.CANME.all; /*----------以下代码是配置接受邮箱的相关代码------------*/ //邮箱1相关配置 ECanaMboxes.MBOX1.MSGCTRL.bit.DLC = 8;//配置数据长度，应该是没意义的; ECanaMboxes.MBOX1.MSGID.all = 0x07909ADC;//设置接收消息的有效ID ECanaMboxes.MBOX1.MSGID.bit.AME =1;//屏蔽使能位,如果需要使用屏蔽,必须将该位置1 ECanaMboxes.MBOX1.MSGID.bit.IDE = CAN_ID_EXT; /* LAMn[28:0] 这些位启用一个进入消息的任意标识符位的屏蔽。 1 针对接受到的标识符的相应位， 接受一个 0 或 1（ 无关） 。 0 接收到的标识符位值必须与 MSGID 寄存器的相应标识符位相匹配。 */ ECanaLAMRegs.LAM1.all = 0x000000F;// /* LAMI 本地接受屏蔽标识符扩展位 1 可以接收标准和扩展帧。 在扩展帧的情况下， 标识符的所有 29 位被存储在邮箱中， 本地接受屏 蔽寄存器的所有 29 位被过滤器使用。 在一个标准帧的情况下， 只有标识符的头 11 个位（ 28 至 18 位） 和本地接受屏蔽被使用。 0 存储在邮箱中的标识符扩展位决定了哪些消息应该被接收到 */ ECanaLAMRegs.LAM1.bit.LAMI = 1; //邮箱31相关配置 ECanaMboxes.MBOX31.MSGCTRL.bit.DLC = 8;//配置数据长度，应该是没意义的; ECanaMboxes.MBOX31.MSGID.all = 0x07909ABC;//设置接收消息的有效ID ECanaMboxes.MBOX31.MSGID.bit.AME =1;//屏蔽使能位, ECanaMboxes.MBOX31.MSGID.bit.IDE = CAN_ID_EXT; /* LAM[28:0] 这些位启用一个进入消息的任意标识符位的屏蔽。 1 针对接受到的标识符的相应位， 接受一个 0 或 1（ 无关） 。 0 接收到的标识符位值必须与 MSGID 寄存器的相应标识符位相匹配。 */ ECanaLAMRegs.LAM31.all = 0x000000F;// /* LAMI 本地接受屏蔽标识符扩展位 1 可以接收标准和扩展帧。 在扩展帧的情况下， 标识符的所有 29 位被存储在邮箱中,本地接受屏蔽寄 存器的所有 29 位被过滤器使用。 在一个标准帧的情况下， 只有标识符的头 11 个位（ 28 至 18 位） 和本地接受屏蔽被使用。 0 存储在邮箱中的标识符扩展位决定了哪些消息应该被接收到 */ ECanaLAMRegs.LAM31.bit.LAMI = 1; ECanaRegs.CANRMP.all = 0xFFFFFFFF; ECanaShadow.CANMD.all = ECanaRegs.CANMD.all; ECanaShadow.CANMD.bit.MD1 = 1; ECanaShadow.CANMD.bit.MD31 = 1; ECanaRegs.CANMD.all = ECanaShadow.CANMD.all; ECanaShadow.CANME.all = ECanaRegs.CANME.all; ECanaShadow.CANME.bit.ME1 = 1;//使能邮箱1 ECanaShadow.CANME.bit.ME31 = 1;//使能邮箱1 ECanaRegs.CANME.all = ECanaShadow.CANME.all; } void CAN_Rx_IT_Concig(void)//邮箱中断相关配置 { EALLOW; ECanaRegs.CANMIM.bit.MIM1 = 1;//使能中断邮箱1的中断; ECanaRegs.CANMIL.bit.MIL1 = 1;//将中断1连接至中断1; ECanaRegs.CANMIM.bit.MIM31 = 1;//使能中断邮箱31的中断; ECanaRegs.CANMIL.bit.MIL31 = 1;//将中断1连接至中断1; ECanaRegs.CANGIM.bit.I1EN = 1;//使能中断1; EDIS; } //具体的中断函数,在清除GMIF1标志位时,不能通过向GMIF1写1来清除,只能通过向RMPn来清除该标志位 /* CAN总线接收数据的结构体 typedef struct {   unsigned short int StdId;  //标准帧ID,值为0x000到0x7FFF;   unsigned long int ExtId; //扩展帧ID,值为0到0x1FFFFFFF   unsigned char SAE_J1939_Flag;//表示是否使用SAE J1939协议   SAE_ID SAE_J1939_ID;   unsigned char IDE;   //帧类型,可为：CAN_ID_STD(标准帧),CAN_ID_EXT(扩展帧)   unsigned char DLC;  //数据长度，可为0到8   unsigned char MBox_num;//发送所用邮箱编号   unsigned short int Rx_timeout_cnt;   CAN_MSG_DATA CAN_Rx_msg_data; /*!< 帧消息内容,共8字节 */ } CanRxMsg; */ __interrupt void Ecana_isr1(void) { if(ECanaRegs.CANGIF1.bit.GMIF1 == 1) { if(ECanaRegs.CANRMP.bit.RMP1 == 1) { //读取该位是知道当前哪一个邮箱收到数据, can_rx_msg.MBox_num = ECanaRegs.CANGIF1.bit.MIV1; can_rx_msg.DLC = ECanaMboxes.MBOX1.MSGCTRL.bit.DLC; can_rx_msg.IDE = ECanaMboxes.MBOX1.MSGID.bit.IDE; if(can_rx_msg.IDE == CAN_ID_EXT) { can_rx_msg.ExtId = ECanaMboxes.MBOX1.MSGID.all&0x1FFFFFFF; can_rx_msg.SAE_J1939_ID.id = can_rx_msg.ExtId; } else if(can_rx_msg.IDE == CAN_ID_STD) { can_rx_msg.StdId = ECanaMboxes.MBOX1.MSGID.bit.STDMSGID; } can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte0 = ECanaMboxes.MBOX1.MDL.byte.BYTE0; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte1 = ECanaMboxes.MBOX1.MDL.byte.BYTE1; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte2 = ECanaMboxes.MBOX1.MDL.byte.BYTE2; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte3 = ECanaMboxes.MBOX1.MDL.byte.BYTE3; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte4 = ECanaMboxes.MBOX1.MDH.byte.BYTE4; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte5 = ECanaMboxes.MBOX1.MDH.byte.BYTE5; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte6 = ECanaMboxes.MBOX1.MDH.byte.BYTE6; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte7 = ECanaMboxes.MBOX1.MDH.byte.BYTE7; ECanaRegs.CANRMP.bit.RMP1 = 1; } else if(ECanaRegs.CANRMP.bit.RMP31 == 1) { can_rx_msg.MBox_num = ECanaRegs.CANGIF1.bit.MIV1; can_rx_msg.DLC = ECanaMboxes.MBOX31.MSGCTRL.bit.DLC; can_rx_msg.IDE = ECanaMboxes.MBOX31.MSGID.bit.IDE; if(can_rx_msg.IDE == CAN_ID_EXT) { can_rx_msg.ExtId = ECanaMboxes.MBOX31.MSGID.all&0x1FFFFFFF; can_rx_msg.SAE_J1939_ID.id = can_rx_msg.ExtId; } else if(can_rx_msg.IDE == CAN_ID_STD) { can_rx_msg.StdId = ECanaMboxes.MBOX31.MSGID.bit.STDMSGID; } can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte0 = ECanaMboxes.MBOX31.MDL.byte.BYTE0; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte1 = ECanaMboxes.MBOX31.MDL.byte.BYTE1; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte2 = ECanaMboxes.MBOX31.MDL.byte.BYTE2; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte3 = ECanaMboxes.MBOX31.MDL.byte.BYTE3; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte4 = ECanaMboxes.MBOX31.MDH.byte.BYTE4; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte5 = ECanaMboxes.MBOX31.MDH.byte.BYTE5; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte6 = ECanaMboxes.MBOX31.MDH.byte.BYTE6; can_rx_msg.CAN_Rx_msg_data.msg_Byte.byte7 = ECanaMboxes.MBOX31.MDH.byte.BYTE7; ECanaRegs.CANRMP.bit.RMP31 = 1; } } PieCtrlRegs.PIEACK.bit.ACK9 = 1; }