STM32F407 CAN IO设置

在STM32F407微控制器中，要使用CAN总线通信，需要进行以下IO口设置：

1. 选择CAN引脚功能。在STM32F407中，CAN1和CAN2总线有各自的引脚，需要根据具体的硬件连接情况选择引脚功能。例如，若使用CAN1总线的PA11和PA12引脚，则需要将这两个引脚配置为复用功能，并选择CAN1的引脚功能。

2. 配置引脚的上拉电阻。在使用CAN总线时，需要配置引脚的上拉电阻，以确保信号的稳定性和可靠性。

3. 配置CAN控制器。在使用CAN总线时，需要对CAN控制器进行配置，包括波特率、工作模式、过滤器等参数的设置。在STM32F407中，可以使用库函数或寄存器配置的方式进行设置。

以下是一个使用CAN1总线的PA11和PA12引脚的IO设置示例代码：

// 选择CAN引脚功能
GPIO_PinAFConfig(GPIOA, GPIO_PinSource11, GPIO_AF_CAN1);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource12, GPIO_AF_CAN1);

// 配置引脚的上拉电阻
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11 | GPIO_Pin_12;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOA, &GPIO_InitStructure);

// 配置CAN控制器
CAN_InitTypeDef CAN_InitStructure;
CAN_FilterInitTypeDef CAN_FilterInitStructure;

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_InitStructure.CAN_SJW = CAN_SJW_1tq;
CAN_InitStructure.CAN_BS1 = CAN_BS1_6tq;
CAN_InitStructure.CAN_BS2 = CAN_BS2_8tq;
CAN_InitStructure.CAN_Prescaler = 4;
CAN_Init(CAN1, &CAN_InitStructure);

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 = CAN_FIFO0;
CAN_FilterInitStructure.CAN_FilterActivation = ENABLE;
CAN_FilterInit(&CAN_FilterInitStructure);