LPC 2292和LPC1758板之间的CAN通信"帧起始"错误

Question

我正在尝试在几个LPC设备节点之间设置CAN通信.我的设置包括一些写入CAN总线的CAN节点.例如,LPC 2292 CAN控制器可以写入CAN总线,LPC1758可以接收数据.这完全没问题.现在LPC1758有2个CAN控制器,我设置了一个用于接收数据,另一个用于在总线上传输数据作为响应.我还为LPC 1758 CAN 1发送和接收以及CAN 2发送和接收设置了中断处理程序.(我没有LPC 2292的代码.它不在我的控制之下)

我的问题是在LPC1758方面.这里CAN 1接收器能够从其他CAN节点获取数据,因为我可以看到被调用的中断向量处理程序.问题是当LPC 1758 CAN 2 tranmistter写入总线​​时.它会出现总线错误.更具体地说"Start of Frame " error.(我使用Ulink2调试器).现在读取CAN规范,我知道CAN消息的起始帧应该从低(主导)位CAN规范开始; 见第3页

我该如何解决此错误？它不是可配置的寄存器,我可以将第一位设置为0或1.我运行KEIL附带的默认LPC 1758 CAN代码C:\Keil_v5\ARM\Boards\Keil\MCB1700\CAN我认为代码很好,因为当我在KEIL的模拟模式下运行代码时我可以看到CAN通信运行良好.

这个"框架开始"是否是我缺少的其他一些配置的副产品？

Update Code : 

我运行KEIL附带的默认LPC 1758 CAN代码C:\Keil_v5\ARM\Boards\Keil\MCB1700\CAN我认为代码很好,因为当我在KEIL的模拟模式下运行代码时,我可以看到CAN通信工作正常.除了波特率之外,我没有对代码进行任何更改.CAN设置:

/*----------------------------------------------------------------------------
  setup CAN interface.  CAN controller (1..2)
 *----------------------------------------------------------------------------*/
void CAN_setup (uint32_t ctrl)  {
  LPC_CAN_TypeDef *pCAN = (ctrl == 1) ? LPC_CAN1 : LPC_CAN2;

  if (ctrl == 1) {
    LPC_SC->PCONP       |=  (1 << 13);           /* Enable power to CAN1 block */
    LPC_PINCON->PINSEL0 |=  (1 <<  0);           /* Pin P0.0 used as RD1 (CAN1) */
    LPC_PINCON->PINSEL0 |=  (1 <<  2);           /* Pin P0.1 used as TD1 (CAN1) */

    NVIC_EnableIRQ(CAN_IRQn);                    /* Enable CAN interrupt */
  } else {
    LPC_SC->PCONP       |=  (1 << 14);           /* Enable power to CAN2 block */
    LPC_PINCON->PINSEL4 |=  (1 << 14);           /* Pin P2.7 used as RD2 (CAN2) */
    LPC_PINCON->PINSEL4 |=  (1 << 16);           /* Pin P2.8 used as TD2 (CAN2) */

    NVIC_EnableIRQ(CAN_IRQn);                    /* Enable CAN interrupt */
  }

  LPC_CANAF->AFMR = 2;                           /* By default filter is not used */
  pCAN->MOD   = 1;                               /* Enter reset mode */
  pCAN->IER   = 0;                               /* Disable all interrupts */
  pCAN->GSR   = 0;                               /* Clear status register */
  CAN_cfgBaudrate(ctrl, /*250000*/ 100000);                 /* Set bit timing */
  pCAN->IER   = 0x0003;                          /* Enable Tx and Rx interrupt */
    //pCAN->IER   = 0x7FF;

}

这是我的传输和接收代码:

/*----------------------------------------------------------------------------
  wite a message to CAN peripheral and transmit it.  CAN controller (1..2)
 *----------------------------------------------------------------------------*/
void CAN_wrMsg (uint32_t ctrl, CAN_msg *msg)  {
  LPC_CAN_TypeDef *pCAN = (ctrl == 1) ? LPC_CAN1 : LPC_CAN2;
  uint32_t CANData;

  CANData = (((uint32_t) msg->len) << 16)     & 0x000F0000 | 
            (msg->format == EXTENDED_FORMAT ) * 0x80000000 |
            (msg->type   == REMOTE_FRAME)     * 0x40000000;

  if (pCAN->SR & (1<<2))  {                      /* Transmit buffer 1 free */
    pCAN->TFI1  = CANData;                       /* Write frame informations */
    pCAN->TID1 = msg->id;                        /* Write CAN message identifier */
    pCAN->TDA1 = *(uint32_t *) &msg->data[0];    /* Write first 4 data bytes */
    pCAN->TDB1 = *(uint32_t *) &msg->data[4];    /* Write second 4 data bytes */
    //pCAN->CMR  = 0x31;                           /* Select Tx1 for Self Tx/Rx */
    pCAN->CMR  = 0x21;                           /* Start transmission without loop-back */ -- Here is when "Start of Frame " error happens

  }
}

收到代码很好但仍然发布

/*----------------------------------------------------------------------------
  read a message from CAN peripheral and release it.  CAN controller (1..2)
 *----------------------------------------------------------------------------*/
void CAN_rdMsg (uint32_t ctrl, CAN_msg *msg)  {
  LPC_CAN_TypeDef *pCAN = (ctrl == 1) ? LPC_CAN1 : LPC_CAN2;
  uint32_t CANData;

                                                 /* Read frame informations */
  CANData = pCAN->RFS;
  msg->format   = (CANData & 0x80000000) == 0x80000000;
  msg->type     = (CANData & 0x40000000) == 0x40000000;
  msg->len      = ((uint8_t)(CANData >> 16)) & 0x0F;

  msg->id = pCAN->RID;                           /* Read CAN message identifier */

  if (msg->type == DATA_FRAME)  {                /* Read the data if received message was DATA FRAME  */ 
    *(uint32_t *) &msg->data[0] = pCAN->RDA;
    *(uint32_t *) &msg->data[4] = pCAN->RDB;
  }
}

波特率计算:

/*----------------------------------------------------------------------------
  configure the requested baudrate.  CAN controller (1..2)
 *----------------------------------------------------------------------------*/
static void CAN_cfgBaudrate (uint32_t ctrl, uint32_t baudrate)  {
  LPC_CAN_TypeDef *pCAN = (ctrl == 1) ? LPC_CAN1 : LPC_CAN2;
  uint32_t result = 0;
  uint32_t nominal_time;

  /* Determine which nominal time to use for PCLK */
  if (((PCLK / 1000000) % 6) == 0) {
    nominal_time = 12;                   /* PCLK based on  72MHz CCLK */
  } else {
    nominal_time = 10;                   /* PCLK based on 100MHz CCLK */
  }

  /* Prepare value appropriate for bit time register */
  result  = (PCLK / nominal_time) / baudrate - 1;
  result &= 0x000003FF;
  result |= CAN_BIT_TIME[nominal_time];

  pCAN->BTR  = result;                           /* Set bit timing */
}

Answer 1

我终于能够摆脱困扰我的“帧开始”错误。我与其他一些 CAN 总线代码作者进行了讨论，他建议我使用相同的 CAN 控制器进行发送和接收。简而言之：

** Does not work** : 
LPC 2292 : CAN 1 Rx & CAN 2 Tx
LPC 1750 : CAN 1 Rx & CAN 2 TX 

** WORKS** :
LPC 2292 : CAN 1 Rx & CAN 1 Tx
LPC 1750 : CAN 1 Rx & CAN 1 TX 

作为一个新手，我可能犯过这个错误。但KEIL提供的默认代码显示使用备用CAN控制器进行发送和传输。我希望这可以帮助别人 。