本帖最后由 地瓜patch 于 2026-1-22 11:32 编辑
我将浮点数转换为字节表示形式，通过 CAN 总线的 HAL_CAN_AddMessage () 函数发送；接收数据时，再将字节数据转换回对应的浮点数。
第一个浮点数的转换和回传都能正常完成，可以将其转为字节形式发送，通过 HAL_CAN_GetMessage () 接收后也能成功转回浮点数。
但处理第二个浮点数时出现问题，接收端接收不到第二个浮点数的数据。
假设浮点变量如下：
float voltage = 7.3789;
float temperature = 21.98290;
第一个 memcpy () 函数调用完全正常。
以下是完整代码：
uint32_t TxMailbox[3]; //create a variable Mailbox to transmit data
uint8_t TxData[8]; // buffer for transmit data
uint8_t RxData[8]; // buffer for recieving data
uint8_t count = 0;
float receivedVoltage;
float receivedTemperatuer;
void HAL_CAN_RxFifo0MsgPendingCallback(CAN_HandleTypeDef *hcan)
{
HAL_CAN_GetRxMessage(hcan, CAN_RX_FIFO0, &RxHeader, RxData); // data will be recieved from CAN_RX_FIFO0, the header will be stored in RxHeader, data will be saved in RxData
memcpy(&receivedVoltage, &RxData, sizeof(receivedVoltage));
memcpy(&receivedTemperatuer, &RxData + sizeof(receivedVoltage), sizeof(receivedTemperatuer));
}
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
char uart_buf[50];
int uart_buf_len;
uint16_t timer_val;
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_I2C1_Init();
MX_CAN2_Init();
MX_TIM6_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
HAL_CAN_Start(&hcan2); // start the can here
HAL_CAN_ActivateNotification(&hcan2, CAN_IT_RX_FIFO0_MSG_PENDING); //activate the notification of recieving data
TxHeader.DLC = 8; // this specifies the length of the data that will be send //8
TxHeader.ExtId = 0; // since we use standard protocol we set it to zero
TxHeader.IDE = CAN_ID_STD; // the IDE is the standard ID
TxHeader.RTR = CAN_RTR_DATA; // we send data not frame
TxHeader.StdId = 0x102; // this is the identifire, must check why 0x103
TxHeader.TransmitGlobalTime = DISABLE;
// HAL_CAN_AddTxMessage(&hcan2, &TxHeader, (uint8_t*)TxData, &TxMailbox);
//uint8_t dev_address1 = 0x16;
uint8_t dev_address = 0x6C;
void SendFloatsOverCAN( float voltageVal, float temperatureVal){
memcpy(&TxData, &voltageVal, sizeof(voltageVal));
memcpy(&TxData + sizeof(voltageVal), &temperatureVal, sizeof(temperatureVal));
HAL_CAN_AddTxMessage(&hcan2, &TxHeader, TxData, TxMailbox);
}
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
main_function(dev_address);
SendFloatsOverCAN(voltage, temperature); // voltage and temperature are the floating points varaibles
HAL_Delay(500);
}
RxData 和 TxData 中存储的是相同的数据
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