用的stm32f2xx_stdperiph_lib里的示例程序做CAN通信测试，环回模式测试OK。正常模式下，用CAN调试软件向板子发数据，始终进不了接收中断
.c文件
int main(void)
{
/* NVIC configuration */
NVIC_Config();
/* CAN configuration */
CAN_Config();
/* Infinite loop */
while(1)
{
Delay();
}
}
void CAN_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
/* CAN GPIOs configuration **************************************************/
/* Enable GPIO clock */
RCC_AHB1PeriphClockCmd(CAN_GPIO_CLK, ENABLE);
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_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);
/* CAN configuration ********************************************************/
/* Enable CAN clock */
RCC_APB1PeriphClockCmd(CAN_CLK, ENABLE);
/* CAN register init */
CAN_DeInit(CANx);
/* CAN cell init */
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_InitStructure.CAN_SJW = CAN_SJW_1tq;
/* CAN Baudrate = 1MBps (CAN clocked at 30 MHz) */
/*CAN_InitStructure.CAN_BS1 = CAN_BS1_6tq;
CAN_InitStructure.CAN_BS2 = CAN_BS2_8tq;
CAN_InitStructure.CAN_Prescaler = 2;
CAN_Init(CANx, &CAN_InitStructure);*/
/* CAN filter init */
#ifdef USE_CAN1
CAN_FilterInitStructure.CAN_FilterNumber = 0;
#else /* USE_CAN2 */
CAN_FilterInitStructure.CAN_FilterNumber = 14;
#endif /* USE_CAN1 */
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);
/* Enable FIFO 0 message pending Interrupt */
CAN_ITConfig(CANx, CAN_IT_FMP0, ENABLE);
}
void NVIC_Config(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
#ifdef USE_CAN1
NVIC_InitStructure.NVIC_IRQChannel = CAN1_RX0_IRQn;
#else /* USE_CAN2 */
NVIC_InitStructure.NVIC_IRQChannel = CAN2_RX0_IRQn;
#endif /* USE_CAN1 */
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);
}
.h头文件
#define USE_CAN1
//#define USE_CAN2
#ifdef USE_CAN1
#define CANx CAN1
#define CAN_CLK RCC_APB1Periph_CAN1
#define CAN_RX_PIN GPIO_Pin_11
#define CAN_TX_PIN GPIO_Pin_12
#define CAN_GPIO_PORT GPIOA
#define CAN_GPIO_CLK RCC_AHB1Periph_GPIOA
#define CAN_AF_PORT GPIO_AF_CAN1
#define CAN_RX_SOURCE GPIO_PinSource11
#define CAN_TX_SOURCE GPIO_PinSource12
#else /*USE_CAN2*/
#define CANx CAN2
#define CAN_CLK (RCC_APB1Periph_CAN1 | RCC_APB1Periph_CAN2)
#define CAN_RX_PIN GPIO_Pin_12
#define CAN_TX_PIN GPIO_Pin_13
#define CAN_GPIO_PORT GPIOB
#define CAN_GPIO_CLK RCC_AHB1Periph_GPIOB
#define CAN_AF_PORT GPIO_AF_CAN2
#define CAN_RX_SOURCE GPIO_PinSource12
#define CAN_TX_SOURCE GPIO_PinSource13
#endif /* USE_CAN1 */
stm32f2xx_it.c 文件中涉及的CAN接收中断程序
#ifdef USE_CAN1
void CAN1_RX0_IRQHandler(void)
{
CAN_Receive(CAN1, CAN_FIFO0, &RxMessage);
CAN_FIFORelease(CAN2, CAN_FIFO0);
}
#endif /* USE_CAN1 */
#ifdef USE_CAN2
/**
* @brief This function handles CAN2 RX0 request.
* @param None
* @retval None
*/
void CAN2_RX0_IRQHandler(void)
{
CAN_Receive(CAN2, CAN_FIFO0, &RxMessage);
CAN_FIFORelease(CAN2, CAN_FIFO0);
}
#endif /* USE_CAN2 */
以上，PC端通过USB-CAN-A2设备与板子连接，CAN调试工具不断发数据。用示波器测收发器的CANH及CANL脚，有脉冲波形，说明CAN口能正常接收到PC端数据。但测收发器的RX脚(RX脚连MCU引出的PA11脚，复用为CAN_RX功能)始终为高电平，没有收到有效信号。
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