CAN BUS Acknowledgment error

Question

I am using STM32F429 CAN bus Program with TJA1041A as CAN Transreciver.The Problem is the messages are not getting acknowledged and herewith I am attaching the code for further reference.I am using PCAN View to see the messages.I kindly request to check the code and tell me if there are any faults.

Code:-

int main(void)
{

 RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN2, ENABLE);

// SystemInit();

    GPIO_InitTypeDef GPIO_InitDef;
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOB, ENABLE);
    GPIO_InitDef.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13;
    GPIO_InitDef.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitDef.GPIO_OType = GPIO_OType_PP;
    GPIO_InitDef.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_InitDef.GPIO_Speed = GPIO_Speed_100MHz;
   GPIO_Init(GPIOB, &GPIO_InitDef);

/* Connect CAN pins to AF */
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource12, GPIO_AF_CAN2); // CAN2_RX
  GPIO_PinAFConfig(GPIOB, GPIO_PinSource13, GPIO_AF_CAN2); // CAN2_TX

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

   GPIO_InitDef.GPIO_Pin = GPIO_Pin_5 | GPIO_Pin_7;
    GPIO_InitDef.GPIO_Mode = GPIO_Mode_OUT;
    GPIO_InitDef.GPIO_OType = GPIO_OType_PP;
    GPIO_InitDef.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_InitDef.GPIO_Speed = GPIO_Speed_100MHz;

  /* Connect PD5 and PD7 pins  for CAN Transreceiver to enable and 
stanby */

 GPIO_Init(GPIOD, &GPIO_InitDef);
     GPIO_SetBits(GPIOD, GPIO_Pin_5|GPIO_Pin_7);

   RCC_ClocksTypeDef     RCC_Clocks;
  CAN_InitTypeDef       CAN_InitStructure;
  CAN_FilterInitTypeDef CAN_FilterInitStructure;

  RCC_GetClocksFreq(&RCC_Clocks);

  CAN_DeInit(CAN2);

  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 ;

  /* quanta 1+14+6 = 21, 21 * 4 = 84, 42000000 / 84 = 5000000 */
  /* CAN Baudrate = 500Kbps (CAN clocked at 42 MHz) Prescale = 4 */

  /* Requires a clock with integer division into APB clock */

  CAN_InitStructure.CAN_SJW = CAN_SJW_1tq; // 1+6+7 = 14, 1+14+6 = 21, 
1+15+5 = 21
  CAN_InitStructure.CAN_BS1 = CAN_BS1_14tq;
  CAN_InitStructure.CAN_BS2 = CAN_BS2_6tq;
  CAN_InitStructure.CAN_Prescaler = 4; // quanta by baudrate - 125kbps

  CAN_Init(CAN2, &CAN_InitStructure);

  /* CAN filter init */
  CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask; // 
IdMask or IdList
  CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_16bit; // 16 
or 32

  CAN_FilterInitStructure.CAN_FilterIdHigh      = 0x0000; // Everything, 
otherwise 11-bit in top bits
  CAN_FilterInitStructure.CAN_FilterIdLow       = 0x0000;
  CAN_FilterInitStructure.CAN_FilterMaskIdHigh  = 0x0000;
  CAN_FilterInitStructure.CAN_FilterMaskIdLow   = 0x0000;

  CAN_FilterInitStructure.CAN_FilterFIFOAssignment = CAN_FIFO0; // Rx
  CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;

  //CAN_FilterInitStructure.CAN_FilterNumber = 0; // CAN1 [ 0..13]

//  CAN_FilterInit(&CAN_FilterInitStructure);

  CAN_FilterInitStructure.CAN_FilterNumber = 14; // CAN2 [14..27]

  CAN_FilterInit(&CAN_FilterInitStructure);
  CAN_ITConfig(CAN2, CAN_IT_FMP0, ENABLE);

 CanTxMsg TxMessage;

  // transmit */
  TxMessage.StdId = 0x321;
  TxMessage.ExtId = 0x00;
  TxMessage.RTR = CAN_RTR_DATA;
  TxMessage.IDE = CAN_ID_STD;
  TxMessage.DLC = 8;

  TxMessage.Data[0] = 0x02;
  TxMessage.Data[1] = 0x11;
  TxMessage.Data[2] = 0x11;
  TxMessage.Data[3] = 0x11;

 while(1)
  {
    uint32_t i;
     int j = 0;
    uint8_t TransmitMailbox = 0;

  TxMessage.Data[4] = (j >>  0) & 0xFF; // Cycling
   TxMessage.Data[5] = (j >>  8) & 0xFF;
    TxMessage.Data[6] = (j >> 16) & 0xFF;
    TxMessage.Data[7] = (j >> 24) & 0xFF;
    j++;

    TransmitMailbox = CAN_Transmit(CAN2, &TxMessage);

i = 0;
    while((CAN_TransmitStatus(CAN2, TransmitMailbox) != CANTXOK) && (i 
!= 0xFFFF)) // Wait on Transmit
    {
      i++;
      CAN2RX();// Pump RX
    }

  }

}

Is there any other CAN node on the bus? Otherwise, no wonder. — Lundin, Nov 25 '14 at 11:58
There ar two nodes inside the microcontroller and I am using only CAN2 because CAN1 is not required — user2870154, Nov 25 '14 at 12:19

score 1 · Answer 1 · answered Nov 25 '14 at 13:28

1

This is the default behavior of any CAN bus. You need at least two CAN controllers on the bus to establish communication. If there is just one node, you will get nothing but error frames.

For debugging purposes, all CAN controllers have a "loop back" debug feature which allows them to acknowledge and listen to their own frames. You must enable this if you are alone on the bus.

Alternatively, if you have two CAN controllers in the same MCU, you can enable both of them and wire them together.

answered Nov 25 '14 at 13:28

Lundin

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I have enable both the CAN controllers from the Microcontrollers but still I am seeing "BUS HEAVY" from the PCAN View. – user2870154 Nov 25 '14 at 14:03
@user2870154 It could be anything then... more likely a hardware error than a software one (you have no bus termination?), but your guess is as good as mine. In order for someone to answer, we'd need the schematics... but since hardware questions are off-topic, you will need to re-post the question at http://electronics.stackexchange.com/ – Lundin Nov 25 '14 at 14:15
I have checked it with the Hardware Schematic. – user2870154 Nov 25 '14 at 14:50
And everything is clear in that..The Problem is only that messages are not acknowledging from the transreceiver to the PCAN – user2870154 Nov 25 '14 at 14:51

score 0 · Answer 2 · answered Dec 12 '16 at 14:27

0

Probably you should enable the transeiver : It should have some voltage in input (Vbat = 12V) and Vi/o and also you need to enable the EN Pin.

answered Dec 12 '16 at 14:27

The Beast

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CAN BUS Acknowledgment error

2 Answers2