I couldnot make STM32F103RC CANBUS work

hello dear forum,

I copied following code from std peripheral library

however I couldnot make it work

what I am doing wrong ?

thank you

---------------

-

RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);

----------------

  NVIC_InitStructure.NVIC_IRQChannel = USB_LP_CAN1_RX0_IRQn;

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 5;

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;

  NVIC_Init(&NVIC_InitStructure);

--------------------------------------

CAN_Initialize(void)

{

  CAN_InitTypeDef        CAN_InitStructure;

  CAN_FilterInitTypeDef  CAN_FilterInitStructure;

  /* 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_LoopBack;

  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=1;

  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);

  return ;

}

---------------------------

void CAN_TXmit(void){

// 

I call this function 10 times every second

  CanTxMsg TxMessage;

/* transmit 1 message */

  TxMessage.StdId=0x00;

  TxMessage.ExtId=0x1234;

  TxMessage.IDE=CAN_ID_EXT;

  TxMessage.RTR=CAN_RTR_DATA;

  TxMessage.DLC=2;

  TxMessage.Data[0]=0xDE;

  TxMessage.Data[1]=0xCA;

  CAN_Transmit(CAN1, &TxMessage);

}

-----------------------

void USB_LP_CAN1_RX0_IRQHandler(void)

{

    i++;  

this variable never increase - i.e. it never enters interrupt handler

  CanRxMsg RxMessage;

  CAN_Receive(CAN1, CAN_FIFO0, &RxMessage);

}