关于使用CAN总线发送数据的问题

只看该作者 · 2017-3-7 12:06

本帖最后由小老千于 2017-3-8 13:04 编辑

在用STM32自带的CAN发送16位数据时明明没有设置高16的值，然而在调试时高位TDHR为0x1B4900，是什么原因？

can初始化：

void CAN_GPIO_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOA, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);
  /* Configure CAN pin: RX */       // PA11
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  /* Configure CAN pin: TX */ // PA12
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
  GPIO_Init(GPIOA, &GPIO_InitStructure);

  //GPIO_PinRemapConfig(GPIO_Remap1_CAN1, ENABLE);
}

void CAN_INIT(void)
{
  CAN_InitTypeDef       CAN_InitStructure;
  CAN_FilterInitTypeDef  CAN_FilterInitStructure;
  CanTxMsg TxMessage;
  /* CAN register init */
  CAN_DeInit(CAN1);
  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_InitStructure.CAN_SJW=CAN_SJW_1tq;
  CAN_InitStructure.CAN_BS1=CAN_BS1_3tq;
  CAN_InitStructure.CAN_BS2=CAN_BS2_2tq;
  CAN_InitStructure.CAN_Prescaler=60;
  CAN_Init(CAN1,&CAN_InitStructure);
  /* CAN filter init */
  CAN_FilterInitStructure.CAN_FilterNumber=1;
  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=CAN_FIFO0;
  CAN_FilterInitStructure.CAN_FilterActivation=ENABLE;
  CAN_FilterInit(&CAN_FilterInitStructure);

  /* CAN FIFO0 message pending interrupt enable */
CAN_ITConfig(CAN1,CAN_IT_FMP0, ENABLE);
}
void can_tx(u16 Data1)
{
  CanTxMsg TxMessage;
  TxMessage.StdId=0x11;
  TxMessage.ExtId=0x0000;
  TxMessage.IDE=CAN_ID_STD;
  TxMessage.RTR=CAN_RTR_DATA;
  TxMessage.DLC=2;
  TxMessage.Data[0]=Data1/256;
  TxMessage.Data[1]=Data1%256;
  CAN_Transmit(CAN1,&TxMessage);
}
计算：
int main(void)
{
      u16 ADC_Value;
      ADCx_Init();
      CAN_INIT();
      CAN_GPIO_Config();
      CAN_NVIC_Configuration();
      while (1)
      {
               filter();
               ADC_Value = After_filter*3300/4096;
            can_tx(ADC_Value);

            Delay(0xffffee);
      }