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STM32F7xx —— CAN通信
一、CAN基础
二、几个重要的CAN函数
三、几个重要的结构
四、接口设计 一、CAN基础
差分信号#xff1a;显性电平对应逻辑0#xff0c;CAN_H和CAN_L差为2.5V#xff1b;隐形电平对应逻辑1#xff0c;CAN_H和CAN_… STM32F7xx —— CAN通信 目录
STM32F7xx —— CAN通信
一、CAN基础
二、几个重要的CAN函数
三、几个重要的结构
四、接口设计 一、CAN基础
差分信号显性电平对应逻辑0CAN_H和CAN_L差为2.5V隐形电平对应逻辑1CAN_H和CAN_L差为0V。
CAN总线的开始和结束都有一个120Ω的终端电阻。
数据帧标准帧11位 扩展帧29位。
其他的一些理论知识就不再赘述了可以参考维基百科对于CAN的描述。
STM32F7xx的bxCAN主要特点支持CAN2.0A和CAN2.0B波特率高达1Mbps支持时间触发具有3个发送邮箱2个接收邮箱可变的过滤器组等。 二、几个重要的CAN函数
HAL_StatusTypeDef HAL_CAN_Init(CAN_HandleTypeDef* hcan); // CAN初始化HAL_StatusTypeDef HAL_CAN_Transmit(CAN_HandleTypeDef *hcan, uint32_t Timeout); // CAN发送HAL_StatusTypeDef HAL_CAN_Receive(CAN_HandleTypeDef *hcan, uint8_t FIFONumber, uint32_t Timeout); // CAN接收三、几个重要的结构
// CAN操作句柄 包含CAN基地址CAN1/CAN2/CAN3 初始化结构 发送接收结构体 其余三个是过程变量
typedef struct
{CAN_TypeDef *Instance; /*! Register base address */CAN_InitTypeDef Init; /*! CAN required parameters */CanTxMsgTypeDef* pTxMsg; /*! Pointer to transmit structure */CanRxMsgTypeDef* pRxMsg; /*! Pointer to reception structure */__IO HAL_CAN_StateTypeDef State; /*! CAN communication state */HAL_LockTypeDef Lock; /*! CAN locking object */__IO uint32_t ErrorCode; /*! CAN Error code */}CAN_HandleTypeDef;
// CAN配置结构体
// 前5个参数来设置 CAN_BTR —— 波特率
// 后6个参数用来设置 CAN_MCR —— 通信相关的控制位
typedef struct
{uint32_t Prescaler; /*! Specifies the length of a time quantum.This parameter must be a number between Min_Data 1 and Max_Data 1024 */uint32_t Mode; /*! Specifies the CAN operating mode.This parameter can be a value of ref CAN_operating_mode */uint32_t SJW; /*! Specifies the maximum number of time quantathe CAN hardware is allowed to lengthen orshorten a bit to perform resynchronization.This parameter can be a value of ref CAN_synchronisation_jump_width */uint32_t BS1; /*! Specifies the number of time quanta in Bit Segment 1.This parameter can be a value of ref CAN_time_quantum_in_bit_segment_1 */uint32_t BS2; /*! Specifies the number of time quanta in Bit Segment 2.This parameter can be a value of ref CAN_time_quantum_in_bit_segment_2 */uint32_t TTCM; /*! Enable or disable the time triggered communication mode.This parameter can be set to ENABLE or DISABLE. */uint32_t ABOM; /*! Enable or disable the automatic bus-off management.This parameter can be set to ENABLE or DISABLE */uint32_t AWUM; /*! Enable or disable the automatic wake-up mode.This parameter can be set to ENABLE or DISABLE */uint32_t NART; /*! Enable or disable the non-automatic retransmission mode.This parameter can be set to ENABLE or DISABLE */uint32_t RFLM; /*! Enable or disable the receive FIFO Locked mode.This parameter can be set to ENABLE or DISABLE */uint32_t TXFP; /*! Enable or disable the transmit FIFO priority.This parameter can be set to ENABLE or DISABLE */
}CAN_InitTypeDef;
// 过滤器设置
typedef struct
{uint32_t FilterIdHigh; /*! Specifies the filter identification number (MSBs for a 32-bitconfiguration, first one for a 16-bit configuration).This parameter must be a number between Min_Data 0x0000 and Max_Data 0xFFFF */uint32_t FilterIdLow; /*! Specifies the filter identification number (LSBs for a 32-bitconfiguration, second one for a 16-bit configuration).This parameter must be a number between Min_Data 0x0000 and Max_Data 0xFFFF */uint32_t FilterMaskIdHigh; /*! Specifies the filter mask number or identification number,according to the mode (MSBs for a 32-bit configuration,first one for a 16-bit configuration).This parameter must be a number between Min_Data 0x0000 and Max_Data 0xFFFF */uint32_t FilterMaskIdLow; /*! Specifies the filter mask number or identification number,according to the mode (LSBs for a 32-bit configuration,second one for a 16-bit configuration).This parameter must be a number between Min_Data 0x0000 and Max_Data 0xFFFF */uint32_t FilterFIFOAssignment; /*! Specifies the FIFO (0 or 1) which will be assigned to the filter.This parameter can be a value of ref CAN_filter_FIFO */uint32_t FilterNumber; /*! Specifies the filter which will be initialized.This parameter must be a number between Min_Data 0 and Max_Data 27 */uint32_t FilterMode; /*! Specifies the filter mode to be initialized.This parameter can be a value of ref CAN_filter_mode */uint32_t FilterScale; /*! Specifies the filter scale.This parameter can be a value of ref CAN_filter_scale */uint32_t FilterActivation; /*! Enable or disable the filter.This parameter can be set to ENABLE or DISABLE. */uint32_t BankNumber; /*! Select the start slave bank filter.This parameter must be a number between Min_Data 0 and Max_Data 28 */}CAN_FilterConfTypeDef;
// 模式 我们使用普通模式
#define CAN_MODE_NORMAL ((uint32_t)0x00000000U) /*! Normal mode */
#define CAN_MODE_LOOPBACK ((uint32_t)CAN_BTR_LBKM) /*! Loopback mode */
#define CAN_MODE_SILENT ((uint32_t)CAN_BTR_SILM) /*! Silent mode */
#define CAN_MODE_SILENT_LOOPBACK ((uint32_t)(CAN_BTR_LBKM | CAN_BTR_SILM)) /*! Loopback combined with silent mode */// 标准帧 扩展帧
#define CAN_ID_STD ((uint32_t)0x00000000U) /*! Standard Id */
#define CAN_ID_EXT ((uint32_t)0x00000004U) /*! Extended Id */
// 数据帧 远程帧
#define CAN_RTR_DATA ((uint32_t)0x00000000U) /*! Data frame */
#define CAN_RTR_REMOTE ((uint32_t)0x00000002U) /*! Remote frame */
// CAN中断使能
__HAL_CAN_ENABLE_IT(__HANDLE__, __INTERRUPT__)
// 接收中断
#define CAN_IT_FMP0 ((uint32_t)CAN_IER_FMPIE0) /*! FIFO 0 message pending interrupt */
#define CAN_IT_FF0 ((uint32_t)CAN_IER_FFIE0) /*! FIFO 0 full interrupt */
#define CAN_IT_FOV0 ((uint32_t)CAN_IER_FOVIE0) /*! FIFO 0 overrun interrupt */
#define CAN_IT_FMP1 ((uint32_t)CAN_IER_FMPIE1) /*! FIFO 1 message pending interrupt */
#define CAN_IT_FF1 ((uint32_t)CAN_IER_FFIE1) /*! FIFO 1 full interrupt */
#define CAN_IT_FOV1 ((uint32_t)CAN_IER_FOVIE1) /*! FIFO 1 overrun interrupt */四、接口设计
与串口类似使用中断接收。先封装单路CAN需要的几个小接口再顶一个列表最后使用统一的接口扫描这个列表。
typedef enum
{CAN_CHANNEL_NONE,CAN_CHANNEL_1,CAN_CHANNEL_2,CAN_CHANNEL_NUM
} can_channel_t;#define CAN1_CHANNEL CAN1
#define CAN1_PREEMPT_PRIO CAN1_RX_PRIORITY
#define CAN1_RX_IRQ CAN1_RX0_IRQn
#define CAN1_RX_IRQ_FUNC CAN1_RX0_IRQHandler
#define CAN1_CLK_ENABLE() __HAL_RCC_CAN1_CLK_ENABLE()
#define CAN1_TX_PORT GPIOA
#define CAN1_TX_PIN GPIO_PIN_12
#define CAN1_TX_AF GPIO_AF9_CAN1
#define CAN1_TX_CONFIG() GPIOConfigExt(CAN1_TX_PORT, CAN1_TX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, CAN1_TX_AF)
#define CAN1_RX_PORT GPIOA
#define CAN1_RX_PIN GPIO_PIN_11
#define CAN1_RX_AF GPIO_AF9_CAN1
#define CAN1_RX_CONFIG() GPIOConfigExt(CAN1_RX_PORT, CAN1_RX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, CAN1_RX_AF)#define CAN2_CHANNEL CAN2
#define CAN2_PREEMPT_PRIO CAN2_RX_PRIORITY
#define CAN2_RX_IRQ CAN2_RX0_IRQn
#define CAN2_RX_IRQ_FUNC CAN2_RX0_IRQHandler
#define CAN2_CLK_ENABLE() __HAL_RCC_CAN2_CLK_ENABLE()
#define CAN2_TX_PORT GPIOB
#define CAN2_TX_PIN GPIO_PIN_6
#define CAN2_TX_AF GPIO_AF9_CAN2
#define CAN2_TX_CONFIG() GPIOConfigExt(CAN2_TX_PORT, CAN2_TX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, CAN2_TX_AF)
#define CAN2_RX_PORT GPIOB
#define CAN2_RX_PIN GPIO_PIN_5
#define CAN2_RX_AF GPIO_AF9_CAN2
#define CAN2_RX_CONFIG() GPIOConfigExt(CAN2_RX_PORT, CAN2_RX_PIN, GPIO_MODE_AF_PP, GPIO_PULLUP, CAN2_RX_AF)// 抽象出一个CAN设备结构体
typedef struct
{CAN_HandleTypeDef handle; // CAN操作句柄CanTxMsgTypeDef tx; // CAN发送CanRxMsgTypeDef rx; // CAN接收can_queue_t recv; // 接收队列} can_dev_t;
// 将每路CAN封装成几个小函数
static can_dev_t can1_dev, can2_dev;static void can1_var_init(void)
{can1_dev.recv can1_queue_recv;CanQueueInit(can1_dev.recv);
}static void can1_gpio_init(void)
{CAN1_TX_CONFIG();CAN1_RX_CONFIG();
}// 波特率 Fpclk1 / ((ts1ts23) * brp) Fpclk1 54M
static void can1_mode_init(void)
{CAN1_CLK_ENABLE();can1_dev.handle.Instance CAN1_CHANNEL;can1_dev.handle.pTxMsg can1_dev.tx;can1_dev.handle.pRxMsg can1_dev.rx;can1_dev.handle.Init.Prescaler 6;can1_dev.handle.Init.Mode CAN_MODE_NORMAL;can1_dev.handle.Init.SJW CAN_SJW_1TQ; // 重新同步跳跃宽度(Tsjw)为tsjw1个时间单位 CAN_SJW_1TQ~CAN_SJW_4TQcan1_dev.handle.Init.BS1 CAN_BS1_11TQ;// tbs1范围CAN_BS1_1TQ~CAN_BS1_16TQcan1_dev.handle.Init.BS2 CAN_BS2_6TQ; // tbs2范围CAN_BS2_1TQ~CAN_BS2_8TQcan1_dev.handle.Init.TTCM DISABLE; // 非时间触发通信模式can1_dev.handle.Init.ABOM ENABLE; // 软件自动离线管理can1_dev.handle.Init.AWUM DISABLE; // 睡眠模式通过软件唤醒(清除CAN-MCR的SLEEP位)can1_dev.handle.Init.NART ENABLE; // 禁止报文自动传送can1_dev.handle.Init.RFLM DISABLE; // 报文不锁定,新的覆盖旧的can1_dev.handle.Init.TXFP DISABLE; // 优先级由报文标识符决定HAL_CAN_Init(can1_dev.handle);
}static void can1_filter_init(void)
{CAN_FilterConfTypeDef filter;filter.FilterNumber 0; // 过滤器0filter.FilterMode CAN_FILTERMODE_IDMASK;filter.FilterScale CAN_FILTERSCALE_32BIT;filter.FilterIdHigh 0;filter.FilterIdLow 0;filter.FilterMaskIdHigh 0;filter.FilterMaskIdLow 0;filter.FilterFIFOAssignment CAN_FILTER_FIFO0; // 过滤器0关联到FIFO0filter.FilterActivation ENABLE; //激活滤波器0//filter.BankNumber14;HAL_CAN_ConfigFilter(can1_dev.handle, filter);
}static void can1_nvic_init(void)
{__HAL_CAN_ENABLE_IT(can1_dev.handle, CAN_IT_FMP0); //FIFO0消息挂号中断允许.HAL_NVIC_SetPriority(CAN1_RX_IRQ, CAN1_RX_PRIORITY, 0);HAL_NVIC_EnableIRQ(CAN1_RX_IRQ);
}static void can2_var_init(void)
{can2_dev.recv can2_queue_recv;CanQueueInit(can2_dev.recv);
}static void can2_gpio_init(void)
{CAN2_TX_CONFIG();CAN2_RX_CONFIG();
}// 波特率 Fpclk1 / ((ts1ts23) * brp) Fpclk1 54M
static void can2_mode_init(void)
{CAN2_CLK_ENABLE();can2_dev.handle.Instance CAN2_CHANNEL;can2_dev.handle.Init.Prescaler 6;can2_dev.handle.Init.Mode CAN_MODE_LOOPBACK;can2_dev.handle.Init.SJW CAN_SJW_1TQ; // 重新同步跳跃宽度(Tsjw)为tsjw1个时间单位 CAN_SJW_1TQ~CAN_SJW_4TQcan2_dev.handle.Init.BS1 CAN_BS1_11TQ;// tbs1范围CAN_BS1_1TQ~CAN_BS1_16TQcan2_dev.handle.Init.BS2 CAN_BS2_6TQ; // tbs2范围CAN_BS2_1TQ~CAN_BS2_8TQcan2_dev.handle.Init.TTCM DISABLE; // 非时间触发通信模式can2_dev.handle.Init.ABOM ENABLE; // 软件自动离线管理can2_dev.handle.Init.AWUM DISABLE; // 睡眠模式通过软件唤醒(清除CAN-MCR的SLEEP位)can2_dev.handle.Init.NART ENABLE; // 禁止报文自动传送can2_dev.handle.Init.RFLM DISABLE; // 报文不锁定,新的覆盖旧的can2_dev.handle.Init.TXFP DISABLE; // 优先级由报文标识符决定HAL_CAN_Init(can2_dev.handle);
}static void can2_filter_init(void)
{CAN_FilterConfTypeDef CAN_FilterInitStructure;CAN_FilterInitStructure.FilterNumber 14;CAN_FilterInitStructure.FilterMode CAN_FILTERMODE_IDMASK;CAN_FilterInitStructure.FilterScale CAN_FILTERSCALE_32BIT;CAN_FilterInitStructure.FilterIdHigh 0;CAN_FilterInitStructure.FilterIdLow 0;CAN_FilterInitStructure.FilterMaskIdHigh 0;CAN_FilterInitStructure.FilterMaskIdLow 0;CAN_FilterInitStructure.FilterFIFOAssignment CAN_FILTER_FIFO0; // 过滤器0关联到FIFO0CAN_FilterInitStructure.FilterActivation ENABLE; //激活滤波器0//CAN_FilterInitStructure.BankNumber14;HAL_CAN_ConfigFilter(can2_dev.handle, CAN_FilterInitStructure);
}static void can2_nvic_init(void)
{__HAL_CAN_ENABLE_IT(can2_dev.handle, CAN_IT_FMP0); //FIFO0消息挂号中断允许1HAL_NVIC_SetPriority(CAN2_RX_IRQ, CAN2_RX_PRIORITY, 0);HAL_NVIC_EnableIRQ(CAN2_RX_IRQ);
}// 每路CAN都有的几个操作使用列表包含然后统一扫描处理
typedef struct
{uint8_t channel;can_dev_t *dev;void (* var_init_cb)(void);void (* gpio_init_cb)(void);void (* mode_init_cb)(void);void (* filter_init_cb)(void);void (* nvic_init_cb)(void);
} can_config_t;static const can_config_t can_configs[]
{{CAN_CHANNEL_1, can1_dev, can1_var_init, can1_gpio_init, can1_mode_init, can1_filter_init, can1_nvic_init},{CAN_CHANNEL_2, can2_dev, can2_var_init, can2_gpio_init, can2_mode_init, can2_filter_init, can2_nvic_init},
};static can_dev_t *can_dev_get(uint8_t channel)
{uint8_t i;for(i 0; i ARRAY_SIZE(can_configs); i){if(channel can_configs[i].channel){return can_configs[i].dev;}}return 0;
}static void can_var_init(uint8_t channel)
{uint8_t i;for(i 0; i ARRAY_SIZE(can_configs); i){if(channel can_configs[i].channel){can_configs[i].var_init_cb();return;}}
}static void can_gpio_init(uint8_t channel)
{uint8_t i;for(i 0; i ARRAY_SIZE(can_configs); i){if(channel can_configs[i].channel){can_configs[i].gpio_init_cb();return;}}
}static void can_mode_init(uint8_t channel)
{uint8_t i;for(i 0; i ARRAY_SIZE(can_configs); i){if(channel can_configs[i].channel){can_configs[i].mode_init_cb();return;}}
}static void can_filter_init(uint8_t channel)
{uint8_t i;for(i 0; i ARRAY_SIZE(can_configs); i){if(channel can_configs[i].channel){can_configs[i].filter_init_cb();return;}}
}static void can_nvic_init(uint8_t channel)
{uint8_t i;for(i 0; i ARRAY_SIZE(can_configs); i){if(channel can_configs[i].channel){can_configs[i].nvic_init_cb();return;}}
}// 对外的接口 初始化 发送和接收
void CanInit(uint8_t channel)
{can_var_init(channel);can_gpio_init(channel);can_mode_init(channel);can_filter_init(channel);can_nvic_init(channel);
}void CanSend(uint8_t channel, can_frame_t *frame)
{can_dev_t *dev can_dev_get(channel);if(dev 0){return;}dev-handle.pTxMsg-StdId frame-StdId;dev-handle.pTxMsg-IDE frame-IDE;dev-handle.pTxMsg-RTR frame-RTR;dev-handle.pTxMsg-DLC frame-DLC;memcpy(dev-handle.pTxMsg-Data, frame-Data, frame-DLC);HAL_CAN_Transmit(dev-handle, 10);
}uint8_t CanRecv(uint8_t channel, can_frame_t *frame)
{can_dev_t *dev can_dev_get(channel);if(dev 0){return 0;}return CanQueueRead(can1_dev.recv, frame);
}// CAN中断
void CAN1_RX_IRQ_FUNC(void)
{HAL_CAN_IRQHandler(can1_dev.handle);
}void CAN2_RX_IRQ_FUNC(void)
{HAL_CAN_IRQHandler(can2_dev.handle);
}void HAL_CAN_RxCpltCallback(CAN_HandleTypeDef *hcan)
{if(hcan (can1_dev.handle)){//CAN_Receive_IT()函数会关闭FIFO0消息挂号中断因此我们需要重新打开__HAL_CAN_ENABLE_IT(can1_dev.handle, CAN_IT_FMP0);//重新开启FIF00消息挂号中断CanQueueWrite(can1_dev.recv, can1_dev.handle.pRxMsg);}else if(hcan (can2_dev.handle)){//CAN_Receive_IT()函数会关闭FIFO0消息挂号中断因此我们需要重新打开__HAL_CAN_ENABLE_IT(can2_dev.handle, CAN_IT_FMP0);//重新开启FIF00消息挂号中断CanQueueWrite(can2_dev.recv, can2_dev.handle.pRxMsg);}
}之所以使用列表的形式是为了方便增加和删除CAN通道和使对外的接口更统一不会出现CAN1Init() CAN2Init()个人习惯问题。
CAN队列可参考CAN队列
