CAN setup on STM32F303

[colinconstant]

I've been working with CAN on the STM32F1 for some time , but I'm having a terrible time trying to get it to work on the F303. I'm hoping someone can tell me what I'm doing wrong. Thanks very much for looking at it.

void can_gpio_config(void)
{
  GPIO_InitTypeDef  GPIO_InitStructure;
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
 
  //Configure CAN RX      
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  
  //Configure CAN TX   
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_Init(GPIOA, &GPIO_InitStructure);
  
  //Connect pins 
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource11, GPIO_AF_7);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_7); 
}
 
void can303_config(void)
{
  CAN_InitTypeDef   CAN_InitStructure;
  CAN_FilterInitTypeDef  CAN_FilterInitStructure;
 
  can_gpio_config();
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);
  
// CAN register init 
  CAN_DeInit(CAN1);
  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 = DISABLE;
  CAN_InitStructure.CAN_Mode = CAN_Mode_Normal; //CAN_Mode_LoopBack; //CAN_Mode_Normal;
  
  // Set the CAN Baudrate = 500K  
  //36,000,000 / (4 * (1 + 9 + 8)) =500,000
  CAN_InitStructure.CAN_SJW  = CAN_SJW_1tq; 
  CAN_InitStructure.CAN_BS1 = CAN_BS1_9tq;
  CAN_InitStructure.CAN_BS2 = CAN_BS2_8tq;
  CAN_InitStructure.CAN_Prescaler = 4; 
  CAN_Init(CAN1, &CAN_InitStructure);
  
// CAN filter init 
  CAN_FilterInitStructure.CAN_FilterNumber = 0;
  CAN_FilterInitStructure.CAN_FilterMode = CAN_FilterMode_IdMask;
  CAN_FilterInitStructure.CAN_FilterScale = CAN_FilterScale_16bit;
  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);
  
  }

Thanks again. I really appreciate it.

[Tesla DeLorean · Accepted solution]

void can_gpio_config(void)
{
  GPIO_InitTypeDef  GPIO_InitStructure = {0};
  RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);
 
  //Configure CAN RX / TX      
  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);
 
  //Connect pins 
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource11, GPIO_AF_9);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_9); 
}

[colinconstant]

That did it. Thank you so much!