can由环回改为正常模式后。。。

风过尘扬

can由环回改为正常模式后。。。 [复制链接]

用的是官方提供的exam,设置为还回模式时，能够正常运行，用zlg的USBCAN-II在can端可以接受数据，改为Normal模式后，就收不到数据了。
翻了很多帖子，貌似常见问题有两个：1、stm32的can信号转发器的供电要5V；2、要有两个有效节点。我的应该都满足了啊，用外部5V供电；USBCAN-II和stm32两个节点。刚接触can，还请多多指点！谢谢。

septem

在stm32端有一个转换成差分信号的小板，上面有120欧的电阻。还有哪里会有问题呢？？？

eestudent

高手们，帮我分析一下啊！
int main(void)
{
  CanRxMsg RxMessage;

  /* System Clocks Configuration */
  RCC_Configuration();
  /* NVIC Configuration */
  NVIC_Configuration();
  LED_Configuration();
  CAN_Configuration();

  while(1)
  {
if (CAN_Polling() == FAILED)
      leddisplay(LEDTWO, LEDON);
else
      leddisplay(LEDTHREE, LEDON);

if (CAN_MessagePending(CAN_FIFO0))
{
      /* receive */
      RxMessage.StdId = 0x00;
      RxMessage.IDE    = CAN_ID_STD;
      RxMessage.DLC    = 0x00;
      RxMessage.Data[0] = 0x00;
      RxMessage.Data[1] = 0x00;
      CAN_Receive(CAN_FIFO0, &RxMessage);
}
  }
}
TestStatus CAN_Polling ( void )
{
CanTxMsg TxMessage;
u32 retry = TIMEOUT;
u8  TransmitMailbox;

leddisplay(LEDONE, LEDOFF);
leddisplay(LEDTWO, LEDOFF);
leddisplay(LEDTHREE, LEDOFF);

while (CAN_Reset() && retry --) ;
if (!retry)
      return FAILED;

TxMessage.StdId = 0x12;
TxMessage.RTR    = CAN_RTR_DATA;
TxMessage.IDE    = CAN_ID_STD;
TxMessage.DLC    = 0x02;
TxMessage.Data[0] = 0x55;
TxMessage.Data[1] = 0xAA;

retry = TIMEOUT;
TransmitMailbox = CAN_Transmit(&TxMessage);  // 执行一次，在USB-CAN接收端收到100多帧。
while ((CAN_TransmitStatus(TransmitMailbox) != CANTXOK) && retry --) ; //状态一直是CANTXPENDING
if (!retry)
      return FAILED;

return PASSED;
}

u8  CAN_Reset ( void )
{
CAN_InitTypeDef       CAN_InitStructure;
CAN_FilterInitTypeDef  CAN_FilterInitStructure;

// CAN register init
CAN_DeInit();
CAN_StructInit(&CAN_InitStructure);

// CAN cell init
CAN_InitStructure.CAN_TTCM    = DISABLE;
CAN_InitStructure.CAN_ABOM    = DISABLE;
CAN_InitStructure.CAN_AWUM    = DISABLE;
CAN_InitStructure.CAN_NART    = DISABLE;
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_8tq;
CAN_InitStructure.CAN_BS2    = CAN_BS2_7tq;
CAN_InitStructure.CAN_Prescaler = 0x05;    // 50 kbps
if (CAN_Init(&CAN_InitStructure) == 0x00)
{
      leddisplay(LEDONE, LEDON);
      return 0xff;
}

// CAN filter init
CAN_FilterInitStructure.CAN_FilterNumber       = 0x00;
CAN_FilterInitStructure.CAN_FilterMode          = CAN_FilterMode_IdMask;
CAN_FilterInitStructure.CAN_FilterScale       = CAN_FilterScale_32bit;
CAN_FilterInitStructure.CAN_FilterIdHigh       = 0x0000;
CAN_FilterInitStructure.CAN_FilterIdLow       = 0x0000;
CAN_FilterInitStructure.CAN_FilterMaskIdHigh    = 0x0000;
CAN_FilterInitStructure.CAN_FilterMaskIdLow    = 0x0000;
CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0x00;
CAN_FilterInitStructure.CAN_FilterActivation    = ENABLE;
CAN_FilterInit(&CAN_FilterInitStructure);

return 0x00;
}

maihy1985

查查看(寄存器CAN_MSR)，CAN处于什么状态，如果处于init状态就不对

nwuwmz

用示波器看下，看有没发数据

action99

谢谢楼上的回答。
在正常模式下，STM32板子发，ZLG的USB-CAN能收到数据。但下面两句的地方有问题。
TransmitMailbox = CAN_Transmit(&TxMessage); // 执行一次，在USB-CAN接收端收到100多帧。
while ((CAN_TransmitStatus(TransmitMailbox) != CANTXOK) && retry --) ; //状态一直是CANTXPENDING