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CAN message

Question asked by Shooja.Rizwin on Aug 21, 2014
Latest reply on Aug 22, 2014 by Shooja.Rizwin
Hi,
I am trying to use CANbus on STM32F303VC6. I get it working in loopback mode. But the message is not getting sent in Normal mode. I have turned on SB21 and SB22 to connect the ports PA11 and PA12 to P2. When I debug the code, I find it getting stuck in CAN_TransmitStatus() function due to pending message. Please point out what might be the problem.

#include "stm32f30x.h"
#include "stm32f3_discovery.h"
#include "stm32f30x_it.h"
#include "stm32f30x_rcc.h"
#include "stm32f30x_can.h"
#include "stm32f30x_gpio.h"
#include "stm32f30x_misc.h"
#include "CAN.h"

void Init_TxMes(CanTxMsg *TxMessage){
          /* Transmit INITIALIZATION*/
     TxMessage->IDE = CAN_ID_STD;
     TxMessage->DLC = 2;
     TxMessage->StdId = 0x321;
     TxMessage->RTR = CAN_RTR_DATA;
}

void Init_RxMes(CanRxMsg *RxMessage)
{
  uint8_t i = 0;

  RxMessage->StdId = 0;
  RxMessage->IDE = CAN_ID_STD;
  RxMessage->DLC = 0;
  RxMessage->FMI = 0;
  for (i = 0; i < 8; i++)
  {
    RxMessage->Data[i] = 0;
  }
}

void CAN_setup(void)
{
    NVIC_InitTypeDef NVIC_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE); //Enable the clock for CAN
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);    
    
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource11 | GPIO_PinSource12 , GPIO_AF_9);   
    
    /* Configure CAN1 RX pin */
   GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
   GPIO_Init(GPIOA, &GPIO_InitStructure);
    
        /* Configure CAN1 TX pin */
     GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
     GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
     GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
     GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
     GPIO_Init(GPIOA, &GPIO_InitStructure);
    

    /* Enable the CAN global Interrupt */
    NVIC_InitStructure.NVIC_IRQChannel = CAN1_SCE_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
    
    NVIC_InitStructure.NVIC_IRQChannel = CAN1_RX1_IRQn;
    NVIC_Init(&NVIC_InitStructure);
    
     CAN_DeInit(CAN1);

     /* Configure CAN1 **************************************************/  
     /* Struct init*/
   CAN_StructInit(&CAN_InitStructure);
   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 = ENABLE;
   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 =6;
     /*Initializes the CAN1 */
   CAN_Init(CAN1,&CAN_InitStructure);
    
    
   /*CAN1 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 = 0x6420;
   CAN_FilterInitStructure.CAN_FilterIdLow = 0x0000;
   CAN_FilterInitStructure.CAN_FilterMaskIdHigh = 0x0000;
   CAN_FilterInitStructure.CAN_FilterMaskIdLow = 0x0000;
   CAN_FilterInitStructure.CAN_FilterFIFOAssignment = 0;
   CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
   CAN_FilterInit(&CAN_FilterInitStructure);
 
}

int main (void)  {
  int i;
  uint8_t TransmitMailbox = 0;

  CAN_setup ();                                   // setup CAN interface
  Init_TxMes(&TxMessage);

    while(1){

         TxMessage.Data[0] = 0xAB;
         TxMessage.Data[1] = 0xCD;

        TransmitMailbox = CAN_Transmit(CAN1,&TxMessage);

        i = 0;
        while((CAN_TransmitStatus(CAN1, TransmitMailbox) != CANTXOK) && (i != 0xFF)) // I put a breakpoint here to check and found the message is pending
            i++;
    }

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