CAN message

rizwin · ‎2014-08-21

Posted on August 21, 2014 at 20:08

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++;

}

Tesla DeLorean · ‎2014-08-21

Posted on August 21, 2014 at 20:56

And you have this connected to a transceiver, and another CAN receiver? ...

Tips, Buy me a coffee, or three.. PayPal Venmo
Up vote any posts that you find helpful, it shows what's working..

rizwin · ‎2014-08-22

Posted on August 22, 2014 at 10:39

Yes. I have it connected to a bus sniffer, PCAN-View.

rizwin · ‎2014-08-22

Posted on August 22, 2014 at 12:46

Found the problem... When the GPIO_PinAFConfig() is done after GPIO_Init(), it started working!!

GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11 | GPIO_Pin_12;

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(GPIOA, &GPIO_InitStructure);

GPIO_PinAFConfig(GPIOA, GPIO_PinSource11, GPIO_AF_9);

GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_9);