stm32f can communication problem?

[koray692]

hello friend.I wri?te a code but unfourtuanetly it doesnt work.In debug RxMessage.Data[0] become 0x58 then TxMessage.Data[0] become 0x59 after that nothing change Let me share code;


#include "stm32f4xx.h"   
#include <stm32f4xx_rcc.h>
#include <stm32f4xx_can.h>
#include <stm32f4xx_gpio.h>

#define CAN_GPIO_PORT GPIOD
#define CAN_RX_SOURCE GPIO_PinSource0 //PD0
#define CAN_TX_SOURCE GPIO_PinSource1 //PD1
#define CAN_AF_PORT GPIO_AF_CAN1
#define CANx CAN1

void CanBusInit(void);

CanTxMsg TxMessage;
CanRxMsg RxMessage;

int main()
{
   int i=0;
   CanBusInit();
   
   TxMessage.StdId=0x123;
   TxMessage.ExtId=0x13375000;
   TxMessage.IDE=CAN_ID_STD;
   TxMessage.RTR=CAN_RTR_DATA;
   TxMessage.DLC=0x1;
   TxMessage.Data[0]=0;
   RxMessage.Data[0]=0;
   CAN_Transmit(CANx,&TxMessage);
   CAN_Receive(CANx,CAN_FIFO0,&RxMessage);
   
//   RxMessage.StdId=;
//   RxMessage.ExtId=;
//   RxMessage.IDE=;
//   RxMessage.RTR=;
//   RxMessage.DLC=;
//   RxMessage.Data=;
//   RxMessage.FMI=;
   
   while(1)
   {
      for(i=0;i<5000000;i++);
      CAN_Transmit(CANx,&TxMessage);
      
           CAN_Receive(CANx,CAN_FIFO0,&RxMessage);
      
      TxMessage.Data[0]=RxMessage.Data[0]+1;
   }
   
}

void CanBusInit(void)
{
   
    GPIO_InitTypeDef GPIO_InitStructure;
    CAN_InitTypeDef CAN_InitStructure;
    CAN_FilterInitTypeDef CANFilter_InitStructure;
    
    /* Enable GPIO clock */
   RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
   /* CAN configuration ********************************************************/
   /* Enable CAN clock */
   RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);
   
   
   /* Connect CAN pins to AF9 */
   GPIO_PinAFConfig(CAN_GPIO_PORT, CAN_RX_SOURCE, CAN_AF_PORT);
   GPIO_PinAFConfig(CAN_GPIO_PORT, CAN_TX_SOURCE, CAN_AF_PORT);

   /* Configure CAN RX and TX pins */
   GPIO_InitStructure.GPIO_Pin = CAN_RX_SOURCE | CAN_TX_SOURCE;
   GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
   GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
   GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
   GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
   GPIO_Init(CAN_GPIO_PORT, &GPIO_InitStructure);

   /* CAN register init */
   CAN_DeInit(CANx);

   /* CAN cell init */
   CAN_InitStructure.CAN_TTCM = DISABLE; // time-triggered communication mode = DISABLED
   CAN_InitStructure.CAN_ABOM = DISABLE; // automatic bus-off management mode = DISABLED
   CAN_InitStructure.CAN_AWUM = DISABLE; // automatic wake-up mode = DISABLED
   CAN_InitStructure.CAN_NART = ENABLE; // non-automatic retransmission mode = ENABLE (To prevent endless spam)
   CAN_InitStructure.CAN_RFLM = DISABLE; // receive FIFO locked mode = DISABLED
   CAN_InitStructure.CAN_TXFP = DISABLE; // transmit FIFO priority = DISABLED
   CAN_InitStructure.CAN_Mode = CAN_Mode_Normal;
   CAN_InitStructure.CAN_SJW = CAN_SJW_1tq;

   /* CAN Baudrate */
   CAN_InitStructure.CAN_BS1 = CAN_BS1_14tq;
   CAN_InitStructure.CAN_BS2 = CAN_BS2_6tq;
   CAN_InitStructure.CAN_Prescaler = 4;
   CAN_Init(CANx, &CAN_InitStructure);

     CANFilter_InitStructure.CAN_FilterActivation = ENABLE;
      CANFilter_InitStructure.CAN_FilterNumber = 14;                                           
      CANFilter_InitStructure.CAN_FilterMode = CAN_FilterMode_IdMask;                 
      CANFilter_InitStructure.CAN_FilterScale = CAN_FilterScale_16bit;                 
      CANFilter_InitStructure.CAN_FilterIdHigh = 0x00;                                         
      CANFilter_InitStructure.CAN_FilterIdLow = 0x00;                                         
      CANFilter_InitStructure.CAN_FilterMaskIdHigh = 0x00;                                     
      CANFilter_InitStructure.CAN_FilterMaskIdLow = 0x00;                                     
      CANFilter_InitStructure.CAN_FilterFIFOAssignment = CAN_Filter_FIFO0;
      CAN_FilterInit(&CANFilter_InitStructure);
}

[magetoo]

hello friend.I wri?te a code but unfourtuanetly it doesnt work.In debug RxMessage.Data[0] become 0x58 then TxMessage.Data[0] become 0x59 after that nothing change Let me share code;


   while(1)
   {
      for(i=0;i<5000000;i++);
      CAN_Transmit(CANx,&TxMessage);
      
           CAN_Receive(CANx,CAN_FIFO0,&RxMessage);
      
      TxMessage.Data[0]=RxMessage.Data[0]+1;
   }

Disclaimer: I'm not an expert on CAN and I've never used those chips.

But that is a tight loop that does nothing except send and receive.  Is it possible that you are filling up a FIFO and you need to take some special action when it is full?

Does CAN_Receive() wait for a CAN frame every time it is called?  Does it work if you slow the program down with a small delay after sending and receiving?

[AndreasF]

I know nothing about CAN, but I suspect this line might be problematic:

Code: [Select]

GPIO_InitStructure.GPIO_Pin = CAN_RX_SOURCE | CAN_TX_SOURCE;
since you

Code: [Select]

#define CAN_RX_SOURCE GPIO_PinSource0 //PD0
#define CAN_TX_SOURCE GPIO_PinSource1 //PD1
However, the GPIO_InitTypeDef structure wants pin definitions like this:

Code: [Select]

#define  GPIO_Pin_0   ((uint16_t)0x0001)
#define  GPIO_Pin_1   ((uint16_t)0x0002)
#define  GPIO_Pin_2   ((uint16_t)0x0004)
...

but the GPIO_PinSource defines are different:

Code: [Select]

#define GPIO_PinSource0            ((uint8_t)0x00)
#define GPIO_PinSource1            ((uint8_t)0x01)
...
(One of these quirks of the Standard Peripheral Library, GPIO_PinAFConfig wants the "PinSource" (i.e. numeric) style pin definition as input, whereas GPIO_InitTypeDef wants a bitfield.)

In other words, your receive pin PD0 should work because GPIO_PinSource1 happens to be identical (apart from type) to GPIO_Pin_0, but your receive pin has not been properly initialized.