stm32F4虚拟端口不工作的原因？如何解决？

我正在尝试使用 STM32f407vgt6 的虚拟端口与我的 win 10 电脑进行通信。我想发送 16 个字节的数据。
我在 cubeMX 中创建了一个基础项目并插入了 cdc_transmit。可以通过虚拟端口将 16 字节的数据发送到我的电脑。我可以在 hterm 中看到传入的数据。
我的问题是，当我添加一些代码行（例如设置一个 ADC）时，无法通过 hterm 或 labview 访问 COM 端口。如果发送缓冲区大于 19 个字节，我会遇到同样的问题。
以下程序不工作。

• /* USER CODE BEGIN Header */
• /**
•   ******************************************************************************
•   * @file           : main.c
•   * @brief          : Main program body
•   ******************************************************************************
•   * @attention
•   *
•   *

  © Copyright (c) 2020 STMicroelectronics.

    * All rights reserved.

•   *
•   * This software component is licensed by ST under BSD 3-Clause license,
•   * the "License"; You may not use this file except in compliance with the
•   * License. You may obtain a copy of the License at:
•   *                        opensource.org/licenses/BSD-3-Clause
•   *
•   ******************************************************************************
•   */
• /* USER CODE END Header */
• /* Includes ------------------------------------------------------------------*/
• #include "main.h"
• #include "adc.h"
• #include "dma.h"
• #include "i2c.h"
• #include "i2s.h"
• #include "spi.h"
• #include "tim.h"
• #include "usb_device.h"
• #include "gpio.h"
• /* Private includes ----------------------------------------------------------*/
• /* USER CODE BEGIN Includes */
• /* USER CODE END Includes */
• /* Private typedef -----------------------------------------------------------*/
• /* USER CODE BEGIN PTD */
• /* USER CODE END PTD */
• /* Private define ------------------------------------------------------------*/
• /* USER CODE BEGIN PD */
• #define TX_BUF_SIZE         16
• #define adcSequenz                8
• /* USER CODE END PD */
• /* Private macro -------------------------------------------------------------*/
• /* USER CODE BEGIN PM */
• /* USER CODE END PM */
• /* Private variables ---------------------------------------------------------*/
• /* USER CODE BEGIN PV */
• uint16_t DeviceAdress= 0x20 << 1;
• volatile uint8_t Tx_Flag;
• uint32_t ms_cnt = 0;
• uint8_t txbuff[TX_BUF_SIZE];
• uint32_t cycCnt = 0;
• uint16_t adc1Data[adcSequenz];
• /* USER CODE END PV */
• /* Private function prototypes -----------------------------------------------*/
• void SystemClock_Config(void);
• /* USER CODE BEGIN PFP */
• extern uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t len);
• /* USER CODE END PFP */
• /* Private user code ---------------------------------------------------------*/
• /* USER CODE BEGIN 0 */
• /**
•   * @brief  Period elapsed callback in non blocking mode
•   * @param  htim: TIM handle
•   * @retval None
•   */
• void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
• {
•         uint8_t i;
•         for(i=0; i        {
•                 txbuff = cycCnt;  // AD Wandler simuliert
•         }
•         // Start ADC DMA
•     if (htim->Instance == htim14.Instance)
•     {
•             HAL_ADC_Start(&hadc1);
•             HAL_ADC_Start_DMA(&hadc1, (uint32_t*) adc1Data, adcSequenz);
•         /* Toggle LED */
•             //HAL_GPIO_TogglePin(GPIOD, LD4_Pin);
•             ms_cnt++;
•             if(ms_cnt >= 500)
•             {
•                     Tx_Flag = 1;
•                     ms_cnt = 0;
•             }
•     }
• }
• /* USER CODE END 0 */
• /**
•   * @brief  The application entry point.
•   * @retval int
•   */
• int main(void)
• {
•   /* USER CODE BEGIN 1 */
•   /* USER CODE END 1 */
•   /* MCU Configuration--------------------------------------------------------*/
•   /* Reset of all peripherals, Initializes the Flash interface and the Systick. */
•   HAL_Init();
•   /* USER CODE BEGIN Init */
•   HAL_StatusTypeDef stat = 0;
•   uint8_t adcTxBuffer[16];
•   uint8_t adcRxBuffer[16];
•   uint8_t datatx[2];
•   uint8_t datarx[1];
•   datarx[0]=0x00;
•   /* 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_DMA_Init();
•   MX_I2C1_Init();
•   MX_I2S3_Init();
•   MX_SPI1_Init();
•   MX_USB_DEVICE_Init();
•   MX_ADC1_Init();
•   MX_TIM14_Init();
•   /* USER CODE BEGIN 2 */
•   float show[adcSequenz];
•   int i = 0;
•   //int j = 0;
•   adcTxBuffer[0] = 0x00;
•   adcTxBuffer[1] = 0xF8;
•   stat = HAL_I2C_Mem_Write(&hi2c1, DeviceAdress, 0x02, 2, adcTxBuffer, 2, 100);
•   stat = HAL_I2C_Mem_Read(&hi2c1, DeviceAdress, 0x02, 2, adcRxBuffer, 2, 100);
•   HAL_Delay(1);
•   HAL_GPIO_TogglePin(GPIOA, 1);
•   HAL_Delay(1);
•   HAL_GPIO_TogglePin(GPIOA, 1);
•   //stat = HAL_I2C_Mem_Read(&hi2c1, DeviceAdress, 0x00, 2, adcRxBuffer, 2, 100);
•   /* USER CODE END 2 */
•   /* Infinite loop */
•   /* USER CODE BEGIN WHILE */
•   while (1)
•   {
•           for(i=0; i
•           {
•                   show = (float) adc1Data*(float) 3.3 / (float)0xFFF;
•           }
•           if(Tx_Flag == 1)
•           {
• //                for(j = 0; j < 8; j++)
• //                {
• //                        txbuff[2*j+1] = adc1Data[j] & 0x00FF;
• //                        txbuff[2*j] = (adc1Data[j] & 0xFF00) >> 8;
• //                }
•                   cycCnt++;
•                   Tx_Flag = 0;
•                   CDC_Transmit_FS(txbuff, sizeof(txbuff));
•                   HAL_GPIO_TogglePin(GPIOD, LD4_Pin);
•           }
•     /* USER CODE END WHILE */
•     /* USER CODE BEGIN 3 */
•   }
•   /* USER CODE END 3 */
• }
• /**
•   * @brief System Clock Configuration
•   * @retval None
•   */
• void SystemClock_Config(void)
• {
•   RCC_OscInitTypeDef RCC_OscInitStruct = {0};
•   RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
•   RCC_PeriphCLKInitTypeDef PeriphClkInitStruct = {0};
•   /** Configure the main internal regulator output voltage
•   */
•   __HAL_RCC_PWR_CLK_ENABLE();
•   __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
•   /** Initializes the CPU, AHB and APB busses clocks
•   */
•   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
•   RCC_OscInitStruct.HSEState = RCC_HSE_ON;
•   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
•   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
•   RCC_OscInitStruct.PLL.PLLM = 8;
•   RCC_OscInitStruct.PLL.PLLN = 336;
•   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
•   RCC_OscInitStruct.PLL.PLLQ = 7;
•   if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
•   {
•     Error_Handler();
•   }
•   /** Initializes the CPU, AHB and APB busses clocks
•   */
•   RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
•                               |RCC_CLOCKTYPE_PCLK1|RCC_CLOCKTYPE_PCLK2;
•   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
•   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
•   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;
•   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
•   if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_5) != HAL_OK)
•   {
•     Error_Handler();
•   }
•   PeriphClkInitStruct.PeriphClockSelection = RCC_PERIPHCLK_I2S;
•   PeriphClkInitStruct.PLLI2S.PLLI2SN = 192;
•   PeriphClkInitStruct.PLLI2S.PLLI2SR = 2;
•   if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInitStruct) != HAL_OK)
•   {
•     Error_Handler();
•   }
• }
• /* USER CODE BEGIN 4 */
• /* USER CODE END 4 */
• /**
•   * @brief  This function is executed in case of error occurrence.
•   * @retval None
•   */
• void Error_Handler(void)
• {
•   /* USER CODE BEGIN Error_Handler_Debug */
•   /* User can add his own implementation to report the HAL error return state */
•   /* USER CODE END Error_Handler_Debug */
• }
• #ifdef  USE_FULL_ASSERT
• /**
•   * @brief  Reports the name of the source file and the source line number
•   *         where the assert_param error has occurred.
•   * @param  file: pointer to the source file name
•   * @param  line: assert_param error line source number
•   * @retval None
•   */
• void assert_failed(uint8_t *file, uint32_t line)
• {
•   /* USER CODE BEGIN 6 */
•   /* User can add his own implementation to report the file name and line number,
•      tex: printf("Wrong parameters value: file %s on line %drn", file, line) */
•   /* USER CODE END 6 */
• }
• #endif /* USE_FULL_ASSERT */
• 
  

我附上了一个工作示例。所以我不知道错误在哪里。