Posted on May 17, 2011 at 14:07I don't like the order you initialize things, the clocks to the peripherals, including GPIOD, need to be up and running before you prod the hardware. It is after all synchronous.
uint8_t CAN1_Init(void)
{
uint8_t retVal = CANINITFAILED;
// Initialize clocks into hardware BEFORE configuring them!
// Enable CAN 1 Clock
RCC_APB1PeriphClockCmd(RCC_APB1Periph_CAN1, ENABLE);
// Enable AFIO and GPIOD clock
RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO | RCC_APB2Periph_GPIOD, ENABLE);
CAN_DeInit(CAN1);
GPIO_InitTypeDef GPIO_InitStructure;
// Configure CAN Tx (PD.01) as push-pull
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
GPIO_Init(GPIOD, &GPIO_InitStructure);
// Configure CAN Rx (PD.00) as input floating
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_Init(GPIOD, &GPIO_InitStructure);
// Remap CAN1 to PD0 and PD1
AFIO->MAPR &= ~(AFIO_MAPR_CAN_REMAP);
AFIO->MAPR |= AFIO_MAPR_CAN_REMAP_REMAP3;
// Configure for 1MBit
CAN_InitTypeDef ci;
CAN_StructInit(&ci);
ci.CAN_Prescaler = 4;
ci.CAN_SJW = CAN_SJW_1tq;
ci.CAN_BS1 = CAN_BS1_6tq;
ci.CAN_BS2 = CAN_BS2_2tq;
ci.CAN_TXFP = ENABLE;
retVal = CAN_Init(CAN1, &ci);
if(retVal != CANINITFAILED)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1); // 1:3
// Tx Interrupt channel
NVIC_InitStructure.NVIC_IRQChannel = CAN1_TX_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
// Peripheral tx interrupt enable
CAN_ITConfig(CAN1, CAN_IT_TME, ENABLE);
}
return retVal;
}
