USB虛擬串口（VCP）收發數據

首先進行USB的配置，時鍾配置USB為48Hz，usb選擇device，usb_device選擇VCP，最后在manager中更改heap size為0x600

---

先對vcp初始化

void USB_Status_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStruct = {0};

    /* GPIO Ports Clock Enable */
    __HAL_RCC_GPIOA_CLK_ENABLE();

    /*Configure GPIO pin Output Level */
    HAL_GPIO_WritePin(GPIOA, GPIO_PIN_11 | GPIO_PIN_12, GPIO_PIN_RESET);

    /*Configure GPIO pin : W25Q256_CS_Pin */
    GPIO_InitStruct.Pin = GPIO_PIN_11 | GPIO_PIN_12;
    GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
    GPIO_InitStruct.Pull = GPIO_PULLDOWN;
    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
    HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
    HAL_Delay(10);
}

初始化區域寫入

  USB_Status_Init();

使用CDC_Transmit_FS進行發送數據

 CDC_Transmit_FS(TXT, sizeof(TXT));

（TXT也為u8）

 CDC_Transmit_FS函數位置為usbd_cdc_if.c

優化后

uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
{
  uint8_t result = USBD_OK;
  /* USER CODE BEGIN 7 */
  uint32_t TimeStart = HAL_GetTick();
  USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)hUsbDeviceFS.pClassData;
  //if (hcdc->TxState != 0) return USBD_BUSY;
  while(hcdc->TxState)
  {
      if(HAL_GetTick()-TimeStart > 10)
    return USBD_BUSY;
      else
    break;
  }
  USBD_CDC_SetTxBuffer(&hUsbDeviceFS, Buf, Len);
  result = USBD_CDC_TransmitPacket(&hUsbDeviceFS);
  TimeStart = HAL_GetTick();
  while(hcdc->TxState)
    {
        if(HAL_GetTick()-TimeStart > 10)
          return USBD_BUSY;
    }
  /* USER CODE END 7 */
  return result;
}

---

虛擬串口接收

使用CDC_Receive_FS函數

注意：CDC_Receive_FS()是接收函數。這個函數不需要調用。直接在函數中添加代碼把接受到的數據和數據長度復制到自己定義的接收緩存。

---

uint8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
  /* USER CODE BEGIN 6 */
    p1=(Buf[0]-'0')*1000+(Buf[1]-'0')*100+(Buf[2]-'0')*10+(Buf[3]-'0');
    p2=(Buf[5]-'0')*1000+(Buf[6]-'0')*100+(Buf[7]-'0')*10+(Buf[8]-'0');
  //USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
  USBD_CDC_ReceivePacket(&hUsbDeviceFS);
  //CDC_Transmit_FS(Buf, sizeof(Buf));
  return (USBD_OK);
  /* USER CODE END 6 */
}

此外，不同.c文件中變量互相使用，在A文件中聲明p變量,在B文件中使用時用extern定義