STM32f042 CAN Tx issue

[shyam]

Posted on March 20, 2017 at 14:05

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https://community.st.com/tags♯/?tags=stm32%20can

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https://community.st.com/tags♯/?tags=can%20init

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https://community.st.com/tags♯/?tags=can%20bus

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https://community.st.com/tags♯/?tags=can%20code

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Hi,

      I am trying out CAN communication with STM32F042 Nucleo dev board. I am getting passive error all the time on Tx message. When i try to debug found last_error as passive and Tx_message status as pending. I dint think there is problem in the CAN initialization, my code is attached below. I am out of my thinking. I would be thankful if i can get some suggestions on this.

int main(void)

{ CanTxMsg TxMessage; CanRxMsg RxMessage; static unsigned int TxMailBox=0, Status =0, ErrStatus=0, RxErrCnt=0; /*!< At this stage the microcontroller clock setting is already configured, this is done through SystemInit() function which is called from startup file (startup_stm32f0xx.s) before to branch to application main. To reconfigure the default setting of SystemInit() function, refer to system_stm32f0xx.c file */ RCC_init(); //Clock Setting if (SysTick_Config(SystemCoreClock / 1000)) { /* Capture error */ while (1); } /* CAN configuration */ CAN_Bus_Initialization(); /* Infinite loop */ while(1) {// CAN_SetSpeed(25 ); if(TickCont > 1000) { TickCont=0; TxMessage.IDE = CAN_ID_STD; TxMessage.StdId = 0x07; TxMessage.ExtId = 0x00; TxMessage.RTR = CAN_RTR_DATA; TxMessage.DLC = 1; TxMessage.Data[0] = 5; if(TxMailBox != 4) { TxMailBox = CAN_Transmit(CANx, &TxMessage); } Status=CAN_TransmitStatus(CANx,TxMailBox);// RxMessage.IDE = 0x00;// RxMessage.StdId = CAN_ID_STD;// RxMessage.ExtId = 0x00;// RxMessage.RTR = CAN_RTR_DATA;// RxMessage.DLC = 0;// RxMessage.Data[0] = 0; // CAN_Receive(CANx, CAN_FIFO0, &RxMessage); ErrStatus=CAN_GetLastErrorCode(CAN);// RxErrCnt = CAN_GetReceiveErrorCounter(CAN); if(((CANx->ESR) & (uint8_t)CAN_ESR_EPVF)) { ErrStatus |= CAN_ESR_EPVF; } else { ErrStatus &= ~CAN_ESR_EPVF; } if(((CANx->ESR) & (uint8_t)CAN_ESR_BOFF)) { ErrStatus |= CAN_ESR_BOFF; } else { ErrStatus &= ~CAN_ESR_BOFF; }// Status=CAN_TransmitStatus(CANx,CAN_Transmit(CANx, &TxMessage));// TxErrCnt = CAN_GetLSBTransmitErrorCounter(CAN);

}

}}

//CanTxMsg TxMessage = {0};

void CAN_Bus_Initialization(){ RCC->APB2ENR |= RCC_APB2ENR_SYSCFGCOMPEN; SYSCFG->CFGR1 |= SYSCFG_CFGR1_PA11_PA12_RMP; CAN_Config();}/** * @brief Configures the CAN. * @param None * @retval None */static void CAN_Config(void){ GPIO_InitTypeDef GPIO_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; CAN_InitTypeDef CAN_InitStructure; CAN_FilterInitTypeDef CAN_FilterInitStructure; /* CAN GPIOs configuration **************************************************/

/* Enable GPIO clock */

RCC_AHBPeriphClockCmd(CAN_GPIO_CLK, ENABLE);

/* Connect CAN pins to AF7 */

GPIO_PinAFConfig(CAN_GPIO_PORT, CAN1_RX_PIN_Source, CAN_AF_PORT ); GPIO_PinAFConfig(CAN_GPIO_PORT, CAN1_TX_PIN_Source, CAN_AF_PORT); /* Configure CAN RX and TX pins */ GPIO_InitStructure.GPIO_Pin = CAN_RX_PIN | CAN_TX_PIN ; 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);

/* NVIC configuration *******************************************************/

// NVIC_InitStructure.NVIC_IRQChannel = CEC_CAN_IRQn;// NVIC_InitStructure.NVIC_IRQChannelPriority = 3;// NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;// NVIC_Init(&NVIC_InitStructure);

/* CAN configuration ********************************************************/

/* Enable CAN clock */ RCC_APB1PeriphClockCmd(CAN_CLK, ENABLE); /* CAN register init */ CAN_DeInit(CANx); CAN_StructInit(&CAN_InitStructure);

/* CAN cell init */

CAN_InitStructure.CAN_TTCM = DISABLE; CAN_InitStructure.CAN_ABOM = ENABLE; 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 Baudrate = 1MBps (CAN clocked at 48 MHz) */&sharpif 1 // Sample-Pint : 50% CAN_InitStructure.CAN_BS1 = CAN_BS1_9tq; CAN_InitStructure.CAN_BS2 = CAN_BS2_8tq; CAN_InitStructure.CAN_Prescaler = 2;&sharpelse // Sample-Pint : 87.5% CAN_InitStructure.CAN_BS1 = CAN_BS1_13tq; CAN_InitStructure.CAN_BS2 = CAN_BS2_2tq;// ErrStatus=CAN_GetLastErrorCode(CAN); CAN_InitStructure.CAN_Prescaler = 12;

&sharpendif

CAN_Init(CANx, &CAN_InitStructure);

/* CAN filter init */

CAN_FilterInitStructure.CAN_FilterNumber = 0; 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 = 0; CAN_FilterInitStructure.CAN_FilterActivation = ENABLE; CAN_FilterInit(&CAN_FilterInitStructure); // /* CAN FIFO0 message pending interrupt enable */// CAN_ITConfig(CANx, CAN_IT_FMP0, ENABLE); /* Enable FIFO 0 message pending Interrupt */// CAN_ITConfig(CANx, CAN_IT_FMP0, ENABLE);}

in regards,

Sundar.

#stm32-can #can-code #stm32f042can #stm32f042-swd #can-init #can-bus

[shyam]

Posted on March 21, 2017 at 08:14

Error which i was getting is Form error and i debugged in scope to check the message, found some extra bits getting added to frame. 

thanks in advance.