STM32HAL库can通断通讯

CAN总线断电检测可以通过在CAN硬件上使用断电检测电路实现。在STM32上，可以使用HAL库函数来检测CAN总线的状态。以下是一个简单的示例代码，演示了如何使用STM32HAL库进行CAN通断通讯：

#include "main.h"
#include "stm32f4xx_hal.h"

CAN_HandleTypeDef hcan1;
uint8_t can_tx_data[8] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF};
uint8_t can_rx_data[8] = {0};

int main(void) {
  HAL_Init();
  SystemClock_Config();

  __HAL_RCC_CAN1_CLK_ENABLE();
  hcan1.Instance = CAN1;
  hcan1.Init.Mode = CAN_MODE_NORMAL;
  hcan1.Init.AutoRetransmission = ENABLE;
  hcan1.Init.AutoBusOff = ENABLE;
  hcan1.Init.ReceiveFifoLocked = DISABLE;
  hcan1.Init.TimeTriggeredMode = DISABLE;
  hcan1.Init.TransmitFifoPriority = DISABLE;
  hcan1.Init.SyncJumpWidth = CAN_SJW_1TQ;
  hcan1.Init.TimeSeg1 = CAN_BS1_13TQ;
  hcan1.Init.TimeSeg2 = CAN_BS2_2TQ;
  hcan1.Init.Prescaler = 2;
  HAL_CAN_Init(&hcan1);

  CAN_FilterTypeDef can_filter;
  can_filter.FilterMode = CAN_FILTERMODE_IDMASK;
  can_filter.FilterIdHigh = 0x0000;
  can_filter.FilterIdLow = 0x0000;
  can_filter.FilterMaskIdHigh = 0x0000;
  can_filter.FilterMaskIdLow = 0x0000;
  can_filter.FilterFIFOAssignment = CAN_FILTER_FIFO0;
  can_filter.FilterBank = 0;
  can_filter.FilterScale = CAN_FILTERSCALE_32BIT;
  can_filter.FilterActivation = ENABLE;
  HAL_CAN_ConfigFilter(&hcan1, &can_filter);

  HAL_CAN_Start(&hcan1);
  HAL_CAN_ActivateNotification(&hcan1, CAN_IT_RX_FIFO0_MSG_PENDING);

  while (1) {
    if (HAL_CAN_GetState(&hcan1) == HAL_CAN_STATE_BUS_OFF) {
      // CAN bus is off
      HAL_GPIO_WritePin(LED_GPIO_Port, LED_Pin, GPIO_PIN_SET);
      HAL_Delay(500);
      HAL_GPIO_WritePin(LED_GPIO_Port, LED_Pin, GPIO_PIN_RESET);
      HAL_Delay(500);
    } else {
      // CAN bus is on
      HAL_GPIO_WritePin(LED_GPIO_Port, LED_Pin, GPIO_PIN_SET);
      HAL_Delay(100);
      HAL_GPIO_WritePin(LED_GPIO_Port, LED_Pin, GPIO_PIN_RESET);
      HAL_Delay(100);
    }

    if (HAL_CAN_GetState(&hcan1) == HAL_CAN_STATE_READY) {
      CAN_TxHeaderTypeDef can_tx_header;
      can_tx_header.StdId = 0x123;
      can_tx_header.RTR = CAN_RTR_DATA;
      can_tx_header.IDE = CAN_ID_STD;
      can_tx_header.DLC = 8;
      uint32_t tx_mailbox;
      HAL_CAN_AddTxMessage(&hcan1, &can_tx_header, can_tx_data, &tx_mailbox);
    }

    HAL_Delay(1000);
  }
}

void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan) {
  CAN_RxHeaderTypeDef can_rx_header;
  HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &can_rx_header, can_rx_data);
}

在这个示例代码中，我们使用了CAN1总线，并在主循环中轮询了CAN总线的状态。如果CAN总线处于“BUS_OFF”状态，我们将LED灯设置为常亮，否则将LED灯闪烁。如果CAN总线处于“READY”状态，我们将发送一个长度为8个字节的CAN消息。我们还注册了一个CAN接收中断回调函数，在接收到CAN消息时，将CAN接收缓冲区中的数据复制到can_rx_data数组中。

需要注意的是，实际应用中需要根据具体的需求进行修改和优化。