虚拟串口控制台

LC2047a 提问时间：2018-11-22 16:41 /

问答
是否解决:

我想要一个虚拟串口与STM32通信。
在其中，我需要从串口获取输入命令，然后实现命令想要做的事情。

我在网上看到很多关于它的例子。然而，它们都在“CDC_Receive_FS”中获得消息并立即重新发送到PC。这意味着消息没有出去。例如，离开“usbd_cdc_if.c”并在“main.c”中发送给PC。

如何在“CDC_Receive_FS”外部收到消息？

如何避免丢失消息？

usbd_cdc_if.c

/**
* @brief Data received over USB OUT endpoint are sent over CDC interface
* through this function.
*
* @note
* This function will block any OUT packet reception on USB endpoint
* untill exiting this function. If you exit this function before transfer
* is complete on CDC interface (ie. using DMA controller) it will result
* in receiving more data while previous ones are still not sent.
*
* @param Buf: Buffer of data to be received
* @param Len: Number of data received (in bytes)
* @retval Result of the operation: USBD_OK if all operations are OK else USBD_FAIL
*/
static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
/* USER CODE BEGIN 6 */
USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
USBD_CDC_ReceivePacket(&hUsbDeviceFS);
USBD_CDC_SetTxBuffer(&hUsbDeviceFS, Buf, Len);
USBD_CDC_TransmitPacket(&hUsbDeviceFS);
return (USBD_OK);
/* USER CODE END 6 */
}

复制代码

如何在main.c中使用“UserRxBufferFS”和“UserTxBufferFS”？

/** @defgroup USBD_CDC_IF_Private_Variables USBD_CDC_IF_Private_Variables
* @brief Private variables.
* @{
*/
/* Create buffer for reception and transmission */
/* It's up to user to redefine and/or remove those define */
/** Received data over USB are stored in this buffer */
uint8_t UserRxBufferFS[APP_RX_DATA_SIZE];
/** Data to send over USB CDC are stored in this buffer */
uint8_t UserTxBufferFS[APP_TX_DATA_SIZE];

复制代码

赞收藏 1 评论2 发布时间：2018-11-22 16:41

2个回答

LC2047a 回答时间：2018-11-23 08:42:47

我正在使用Blue Pill板。

我在下面找到了例子。它教我成功在外面使用“UserRxBufferFS”和“* Len”。

/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* This notice applies to any and all portions of this file
* that are not between comment pairs USER CODE BEGIN and
* USER CODE END. Other portions of this file, whether
* inserted by the user or by software development tools
* are owned by their respective copyright owners.
*
* Copyright (c) 2018 STMicroelectronics International N.V.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted, provided that the following conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of other
* contributors to this software may be used to endorse or promote products
* derived from this software without specific written permission.
* 4. This software, including modifications and/or derivative works of this
* software, must execute solely and exclusively on microcontroller or
* microprocessor devices manufactured by or for STMicroelectronics.
* 5. Redistribution and use of this software other than as permitted under
* this license is void and will automatically terminate your rights under
* this license.
*
* THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
* RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT
* SHALL STMICROELECTRONICS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "stm32f1xx_hal.h"
#include "usart.h"
#include "usb_device.h"
#include "gpio.h"
/* USER CODE BEGIN Includes */
#include "usb_device.h"
#include "usbd_core.h"
#include "usbd_desc.h"
#include "usbd_cdc.h"
#include "usbd_cdc_if.h"
/* USER CODE END Includes */
/* Private variables ---------------------------------------------------------*/
/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/
// http://www.smilefrog.net/?p=763 "USB-CDC (VCP)“
extern uint8_t UserRxBufferFS[]; // declare receive data external variable
extern uint8_t DataLen; // declare receive buffer external variable
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
/* USER CODE BEGIN PFP */
/* Private function prototypes -----------------------------------------------*/
/* USER CODE END PFP */
/* USER CODE BEGIN 0 */
/* USER CODE END 0 */
/**
* @brief The application entry point.
*
* @retval None
*/
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 */
/* 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_USART1_UART_Init();
MX_USB_DEVICE_Init();
/* USER CODE BEGIN 2 */
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
/* to ensure the code is running */
//HAL_GPIO_TogglePin(GPIOB, GPIO_PIN_12);
//HAL_Delay(1000);
if(DataLen > 0)
{
while(CDC_Transmit_FS(UserRxBufferFS, DataLen));
DataLen = 0;
}
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct;
RCC_ClkInitTypeDef RCC_ClkInitStruct;
RCC_PeriphCLKInitTypeDef PeriphClkInit;
/**Initializes the CPU, AHB and APB busses clocks
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
RCC_OscInitStruct.HSEState = RCC_HSE_ON;
RCC_OscInitStruct.HSEPredivValue = RCC_HSE_PREDIV_DIV1;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLMUL = RCC_PLL_MUL9;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
/**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_DIV2;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
PeriphClkInit.PeriphClockSelection = RCC_PERIPHCLK_USB;
PeriphClkInit.UsbClockSelection = RCC_USBCLKSOURCE_PLL_DIV1_5;
if (HAL_RCCEx_PeriphCLKConfig(&PeriphClkInit) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
/**Configure the Systick interrupt time
*/
HAL_SYSTICK_Config(HAL_RCC_GetHCLKFreq()/1000);
/**Configure the Systick
*/
HAL_SYSTICK_CLKSourceConfig(SYSTICK_CLKSOURCE_HCLK);
/* SysTick_IRQn interrupt configuration */
HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
}
/* USER CODE BEGIN 4 */
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @param file: The file name as string.
* @param line: The line in file as a number.
* @retval None
*/
void _Error_Handler(char *file, int line)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
while(1)
{
}
/* 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 %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

复制代码

/**
******************************************************************************
* @file : usbd_cdc_if.c///
* @version : v2.0_Cube
* @brief : Usb device for Virtual Com Port.
******************************************************************************
* This notice applies to any and all portions of this file
* that are not between comment pairs USER CODE BEGIN and
* USER CODE END. Other portions of this file, whether
* inserted by the user or by software development tools
* are owned by their respective copyright owners.
*
* Copyright (c) 2018 STMicroelectronics International N.V.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted, provided that the following conditions are met:
*
* 1. Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. Neither the name of STMicroelectronics nor the names of other
* contributors to this software may be used to endorse or promote products
* derived from this software without specific written permission.
* 4. This software, including modifications and/or derivative works of this
* software, must execute solely and exclusively on microcontroller or
* microprocessor devices manufactured by or for STMicroelectronics.
* 5. Redistribution and use of this software other than as permitted under
* this license is void and will automatically terminate your rights under
* this license.
*
* THIS SOFTWARE IS PROVIDED BY STMICROELECTRONICS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS, IMPLIED OR STATUTORY WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
* PARTICULAR PURPOSE AND NON-INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY
* RIGHTS ARE DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. IN NO EVENT
* SHALL STMICROELECTRONICS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include "usbd_cdc_if.h"
/* USER CODE BEGIN INCLUDE */
/* USER CODE END INCLUDE */
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PV */
/* Private variables ---------------------------------------------------------*/
/* USER CODE END PV */
/** @addtogroup STM32_USB_OTG_DEVICE_LIBRARY
* @brief Usb device library.
* @{
*/
/** @addtogroup USBD_CDC_IF
* @{
*/
/** @defgroup USBD_CDC_IF_Private_TypesDefinitions USBD_CDC_IF_Private_TypesDefinitions
* @brief Private types.
* @{
*/
/* USER CODE BEGIN PRIVATE_TYPES */
/* USER CODE END PRIVATE_TYPES */
/**
* @}
*/
/** @defgroup USBD_CDC_IF_Private_Defines USBD_CDC_IF_Private_Defines
* @brief Private defines.
* @{
*/
/* USER CODE BEGIN PRIVATE_DEFINES */
/* Define size for the receive and transmit buffer over CDC */
/* It's up to user to redefine and/or remove those define */
#define APP_RX_DATA_SIZE 64
#define APP_TX_DATA_SIZE 64
/* USER CODE END PRIVATE_DEFINES */
/**
* @}
*/
/** @defgroup USBD_CDC_IF_Private_Macros USBD_CDC_IF_Private_Macros
* @brief Private macros.
* @{
*/
/* USER CODE BEGIN PRIVATE_MACRO */
/* USER CODE END PRIVATE_MACRO */
/**
* @}
*/
/** @defgroup USBD_CDC_IF_Private_Variables USBD_CDC_IF_Private_Variables
* @brief Private variables.
* @{
*/
/* Create buffer for reception and transmission */
/* It's up to user to redefine and/or remove those define */
/** Received data over USB are stored in this buffer */
uint8_t UserRxBufferFS[APP_RX_DATA_SIZE];
/** Data to send over USB CDC are stored in this buffer */
uint8_t UserTxBufferFS[APP_TX_DATA_SIZE];
/* USER CODE BEGIN PRIVATE_VARIABLES */
// http://www.smilefrog.net/?p=763 "USB-CDC (VCP)“
uint8_t DataLen; // define receive buffer length variable
/* USER CODE END PRIVATE_VARIABLES */
/**
* @}
*/
/** @defgroup USBD_CDC_IF_Exported_Variables USBD_CDC_IF_Exported_Variables
* @brief Public variables.
* @{
*/
extern USBD_HandleTypeDef hUsbDeviceFS;
/* USER CODE BEGIN EXPORTED_VARIABLES */
/* USER CODE END EXPORTED_VARIABLES */
/**
* @}
*/
/** @defgroup USBD_CDC_IF_Private_FunctionPrototypes USBD_CDC_IF_Private_FunctionPrototypes
* @brief Private functions declaration.
* @{
*/
static int8_t CDC_Init_FS(void);
static int8_t CDC_DeInit_FS(void);
static int8_t CDC_Control_FS(uint8_t cmd, uint8_t* pbuf, uint16_t length);
static int8_t CDC_Receive_FS(uint8_t* pbuf, uint32_t *Len);
/* USER CODE BEGIN PRIVATE_FUNCTIONS_DECLARATION */
/* USER CODE END PRIVATE_FUNCTIONS_DECLARATION */
/**
* @}
*/
USBD_CDC_ItfTypeDef USBD_Interface_fops_FS =
{
CDC_Init_FS,
CDC_DeInit_FS,
CDC_Control_FS,
CDC_Receive_FS
};
/* Private functions ---------------------------------------------------------*/
/**
* @brief Initializes the CDC media low layer over the FS USB IP
* @retval USBD_OK if all operations are OK else USBD_FAIL
*/
static int8_t CDC_Init_FS(void)
{
/* USER CODE BEGIN 3 */
/* Set Application Buffers */
USBD_CDC_SetTxBuffer(&hUsbDeviceFS, UserTxBufferFS, 0);
USBD_CDC_SetRxBuffer(&hUsbDeviceFS, UserRxBufferFS);
return (USBD_OK);
/* USER CODE END 3 */
}
/**
* @brief DeInitializes the CDC media low layer
* @retval USBD_OK if all operations are OK else USBD_FAIL
*/
static int8_t CDC_DeInit_FS(void)
{
/* USER CODE BEGIN 4 */
return (USBD_OK);
/* USER CODE END 4 */
}
/**
* @brief Manage the CDC class requests
* @param cmd: Command code
* @param pbuf: Buffer containing command data (request parameters)
* @param length: Number of data to be sent (in bytes)
* @retval Result of the operation: USBD_OK if all operations are OK else USBD_FAIL
*/
static int8_t CDC_Control_FS(uint8_t cmd, uint8_t* pbuf, uint16_t length)
{
/* USER CODE BEGIN 5 */
switch(cmd)
{
case CDC_SEND_ENCAPSULATED_COMMAND:
break;
case CDC_GET_ENCAPSULATED_RESPONSE:
break;
case CDC_SET_COMM_FEATURE:
break;
case CDC_GET_COMM_FEATURE:
break;
case CDC_CLEAR_COMM_FEATURE:
break;
/*******************************************************************************/
/* Line Coding Structure */
/*-----------------------------------------------------------------------------*/
/* Offset | Field | Size | Value | Description */
/* 0 | dwDTERate | 4 | Number |Data terminal rate, in bits per second*/
/* 4 | bCharFormat | 1 | Number | Stop bits */
/* 0 - 1 Stop bit */
/* 1 - 1.5 Stop bits */
/* 2 - 2 Stop bits */
/* 5 | bParityType | 1 | Number | Parity */
/* 0 - None */
/* 1 - Odd */
/* 2 - Even */
/* 3 - Mark */
/* 4 - Space */
/* 6 | bDataBits | 1 | Number Data bits (5, 6, 7, 8 or 16). */
/*******************************************************************************/
case CDC_SET_LINE_CODING:
break;
case CDC_GET_LINE_CODING:
break;
case CDC_SET_CONTROL_LINE_STATE:
break;
case CDC_SEND_BREAK:
break;
default:
break;
}
return (USBD_OK);
/* USER CODE END 5 */
}
/**
* @brief Data received over USB OUT endpoint are sent over CDC interface
* through this function.
*
* @note
* This function will block any OUT packet reception on USB endpoint
* untill exiting this function. If you exit this function before transfer
* is complete on CDC interface (ie. using DMA controller) it will result
* in receiving more data while previous ones are still not sent.
*
* @param Buf: Buffer of data to be received
* @param Len: Number of data received (in bytes)
* @retval Result of the operation: USBD_OK if all operations are OK else USBD_FAIL
*/
static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
/* USER CODE BEGIN 6 */
USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
USBD_CDC_ReceivePacket(&hUsbDeviceFS);
DataLen = *Len; //assign receive buffer length, don't edit any other!!!
return (USBD_OK);
/* USER CODE END 6 */
}
/**
* @brief CDC_Transmit_FS
* Data to send over USB IN endpoint are sent over CDC interface
* through this function.
* @note
*
*
* @param Buf: Buffer of data to be sent
* @param Len: Number of data to be sent (in bytes)
* @retval USBD_OK if all operations are OK else USBD_FAIL or USBD_BUSY
*/
uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len)
{
uint8_t result = USBD_OK;
/* USER CODE BEGIN 7 */
USBD_CDC_HandleTypeDef *hcdc = (USBD_CDC_HandleTypeDef*)hUsbDeviceFS.pClassData;
if (hcdc->TxState != 0){
return USBD_BUSY;
}
USBD_CDC_SetTxBuffer(&hUsbDeviceFS, Buf, Len);
result = USBD_CDC_TransmitPacket(&hUsbDeviceFS);
/* USER CODE END 7 */
return result;
}
/* USER CODE BEGIN PRIVATE_FUNCTIONS_IMPLEMENTATION */
/* USER CODE END PRIVATE_FUNCTIONS_IMPLEMENTATION */
/**
* @}
*/
/**
* @}
*/
/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

复制代码

问题1。
为什么使用“while（CDC_Transmit_FS（UserRxBufferFS，DataLen））;”？
我尝试只使用“CDC_Transmit_FS（UserRxBufferFS，DataLen）”，它似乎也有用。
它与下一步“DataLen = 0”（重置DataLen）有关吗？

问题2。
只有当我在主循环中添加一些延迟（以模拟另一个任务）时，它会丢失消息或只是回转最后一个字。
如何避免丢失？

请指教！

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bjflsk 回答时间：2018-11-28 12:14:26

CDC_Transmit_FS（UserRxBufferFS，DataLen）；一次不一定能够发送成功。因为你发送的时候USB可能处于BUSY等状态。
所以采用while（CDC_Transmit_FS（UserRxBufferFS，DataLen））；不断发送，直到发送成功。
DataLen = 0；原作者借用了这个变量来判断已接收到数据---- if(DataLen > 0)----，此处把它设置为0。但不建议这样做。这存在竞争风险。你的第2个问题有可能和这也相关。
问题2请参照管理员分享的文章：
https://www.stmcu.org.cn/module/forum/thread-613504-1-6.html

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