libusb开发流程

前言
USB的用途就不多说了，下面的内容主要就是讲解如何利用ST提供的USB驱动库和libusb上位机驱动库实现一个USB数据传输功能，为了降低开发难度，我们仅仅讲解Bulk传输模式，当然这也是用得比较多的传输模式。

开发流程
1，完成STM32单片机端的USB程序；
2，利用linusb自带的inf-wizard工具生成USB驱动；
3，基于libusb编写USB通信程序；
4，测试PC和单片机的数据通信；

STM32程序编写
1，完成描述符的修改，修改后的描述符如下（在usb_desc.c文件中）
设备描述符：

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const uint8_t CustomHID_DeviceDescriptor[CUSTOMHID_SIZ_DEVICE_DESC] = {     0x12,                       /*bLength */     USB_DEVICE_DESCRIPTOR_TYPE, /*bDescriptorType*/     0x00,                       /*bcdUSB */     0x02,     0x00,                       /*bDeviceClass*/     0x00,                       /*bDeviceSubClass*/     0x00,                       /*bDeviceProtocol*/     0x40,                       /*bMaxPacketSize40*/     LOBYTE(USBD_VID),           /*idVendor*/     HIBYTE(USBD_VID),           /*idVendor*/     LOBYTE(USBD_PID),           /*idVendor*/     HIBYTE(USBD_PID),           /*idVendor*/     0x00,                       /*bcdDevice rel. 2.00*/     0x02,     1,                          /*Index of string descriptor describing manufacturer */     2,                          /*Index of string descriptor describing product*/     3,                          /*Index of string descriptor describing the device serial number */     0x01                        /*bNumConfigurations*/ }; /* CustomHID_DeviceDescriptor */

配置描述符：

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const uint8_t CustomHID_ConfigDescriptor[CUSTOMHID_SIZ_CONFIG_DESC] = {     0x09, /* bLength: Configuation Descriptor size */     USB_CONFIGURATION_DESCRIPTOR_TYPE, /* bDescriptorType: Configuration */     CUSTOMHID_SIZ_CONFIG_DESC,     /* wTotalLength: Bytes returned */     0x00,     0x01,         /* bNumInterfaces: 1 interface */     0x01,         /* bConfigurationValue: Configuration value */     0x00,         /* iConfiguration: Index of string descriptor describing                                  the configuration*/     0xE0,         /* bmAttributes: Bus powered */                   /*Bus powered: 7th bit, Self Powered: 6th bit, Remote wakeup: 5th bit, reserved: 4..0 bits */     0xFA,         /* MaxPower 500 mA: this current is used for detecting Vbus */     /************** Descriptor of Custom HID interface ****************/     /* 09 */     0x09,         /* bLength: Interface Descriptor size */     USB_INTERFACE_DESCRIPTOR_TYPE,/* bDescriptorType: Interface descriptor type */     0x00,         /* bInterfaceNumber: Number of Interface */     0x00,         /* bAlternateSetting: Alternate setting */     0x04,         /* bNumEndpoints */     0xDC,         /* bInterfaceClass: Class code = 0DCH */     0xA0,         /* bInterfaceSubClass : Subclass code = 0A0H */     0xB0,         /* nInterfaceProtocol : Protocol code = 0B0H */     0,            /* iInterface: Index of string descriptor */     /******************** endpoint descriptor ********************/     /* 18 */     0x07,         /* endpoint descriptor length = 07H */     USB_ENDPOINT_DESCRIPTOR_TYPE, /* endpoint descriptor type = 05H */     0x81,         /* endpoint 1 IN */     0x02,                                        /* bulk transfer = 02H */     0x40,0x00,    /* endpoint max packet size = 0040H */     0x00,         /* the value is invalid when bulk transfer */       0x07,         /* endpoint descriptor length = 07H */     USB_ENDPOINT_DESCRIPTOR_TYPE, /* endpoint descriptor type = 05H */     0x01,         /* endpoint 1 OUT */     0x02,                                        /* bulk transfer = 02H */     0x40,0x00,    /* endpoint max packet size = 0040H */     0x00,         /* the value is invalid when bulk transfer */                       0x07,         /* endpoint descriptor length = 07H */     USB_ENDPOINT_DESCRIPTOR_TYPE, /* endpoint descriptor type = 05H */     0x82,         /* endpoint 2 IN */     0x02,                                        /* bulk transfer = 02H */     0x40,0x00,    /* endpoint max packet size = 0040H */     0x00,         /* the value is invalid when bulk transfer */                       0x07,         /* endpoint descriptor length = 07H */     USB_ENDPOINT_DESCRIPTOR_TYPE, /* endpoint descriptor type = 05H */     0x02,         /* endpoint 2 OUT */     0x02,                                        /* bulk transfer = 02H */     0x40,0x00,    /* endpoint max packet size = 0040H */     0x00,         /* the value is invalid when bulk transfer */ }; /* CustomHID_ConfigDescriptor */

配置描述符就包含了端点描述符，我们用了4个端点，两个BULK-OUT端点，两个BULK-IN端点。

其他的描述符：

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/* USB String Descriptors (optional) */ const uint8_t CustomHID_StringLangID[CUSTOMHID_SIZ_STRING_LANGID] = {     CUSTOMHID_SIZ_STRING_LANGID,     USB_STRING_DESCRIPTOR_TYPE,     0x09,     0x04 }; /* LangID = 0x0409: U.S. English */   const uint8_t CustomHID_StringVendor[CUSTOMHID_SIZ_STRING_VENDOR] = {     CUSTOMHID_SIZ_STRING_VENDOR, /* Size of Vendor string */     USB_STRING_DESCRIPTOR_TYPE,  /* bDescriptorType*/     // Manufacturer: "STMicroelectronics"     'M', 0, 'y', 0, 'U', 0,'S', 0,'B', 0, '_', 0, 'H', 0,'I',0,'D',0 };   const uint8_t CustomHID_StringProduct[CUSTOMHID_SIZ_STRING_PRODUCT] = {     CUSTOMHID_SIZ_STRING_PRODUCT,          /* bLength */     USB_STRING_DESCRIPTOR_TYPE,        /* bDescriptorType */     'B', 0, 'y', 0, ' ', 0, 'e', 0, 'm', 0, 'b', 0,'e',0,'d',0,'-',0,'n',0,'e',0,'t',0 }; uint8_t CustomHID_StringSerial[CUSTOMHID_SIZ_STRING_SERIAL] = {     CUSTOMHID_SIZ_STRING_SERIAL,           /* bLength */     USB_STRING_DESCRIPTOR_TYPE,        /* bDescriptorType */     'x', 0, 'x', 0, 'x', 0,'x', 0,'x', 0, 'x', 0, 'x', 0 };

2，根据端点缓冲区大小配置端点缓冲区地址，配置信息如下（在usb_conf.h文件中）：

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/* buffer table base address */ #define BTABLE_ADDRESS      (0x00)   /* EP0  */ /* rx/tx buffer base address */ #define ENDP0_RXADDR        (0x18) #define ENDP0_TXADDR        (0x58)   /* EP1  */ /* tx buffer base address */ //地址为32位对其,位4的倍数，不能超过 bMaxPacketSize //EP1 #define ENDP1_RXADDR        (0x98) #define ENDP1_TXADDR        (0x98+64) ////EP2 #define ENDP2_RXADDR        (0xA0+64+64) #define ENDP2_TXADDR        (0xA0+64+64+64)

3，初始化每个端点（在usb_prop.c文件中的CustomHID_Reset函数中）

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/* Initialize Endpoint 0 */ SetEPType(ENDP0, EP_CONTROL); SetEPTxStatus(ENDP0, EP_TX_STALL); SetEPRxAddr(ENDP0, ENDP0_RXADDR); SetEPTxAddr(ENDP0, ENDP0_TXADDR); Clear_Status_Out(ENDP0); SetEPRxCount(ENDP0, Device_Property.MaxPacketSize); SetEPRxValid(ENDP0);   /* Initialize Endpoint 1 */        SetEPType(ENDP1, EP_BULK);        SetEPRxAddr(ENDP1, ENDP1_RXADDR);        SetEPTxAddr(ENDP1, ENDP1_TXADDR);        SetEPRxCount(ENDP1, EP_SIZE);        SetEPRxStatus(ENDP1, EP_RX_VALID);  SetEPTxStatus(ENDP1, EP_TX_NAK);   /* Initialize Endpoint 2 */        SetEPType(ENDP2, EP_BULK);        SetEPRxAddr(ENDP2, ENDP2_RXADDR);        SetEPTxAddr(ENDP2, ENDP2_TXADDR);        SetEPRxCount(ENDP2, EP_SIZE);        SetEPRxStatus(ENDP2, EP_RX_VALID);        SetEPTxStatus(ENDP2, EP_TX_NAK);

4，实现端点的回调函数（需要在usb_conf.h中注释掉对应的回调函数宏定义）

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/******************************************************************************* * Function Name  : EP1_OUT_Callback. * Description    : EP1 OUT Callback Routine. * Input          : None. * Output         : None. * Return         : None. *******************************************************************************/ void EP1_OUT_Callback(void) {         EP1_ReceivedCount = GetEPRxCount(ENDP1);         PMAToUserBufferCopy(USB_Receive_Buffer, ENDP1_RXADDR, EP1_ReceivedCount);         SetEPRxStatus(ENDP1, EP_RX_VALID); } /******************************************************************************* * Function Name  : EP2_OUT_Callback. * Description    : EP2 OUT Callback Routine. * Input          : None. * Output         : None. * Return         : None. *******************************************************************************/ void EP2_OUT_Callback(void) {         EP2_ReceivedCount = GetEPRxCount(ENDP2);         PMAToUserBufferCopy(USB_Receive_Buffer, ENDP2_RXADDR, EP2_ReceivedCount);         SetEPRxStatus(ENDP2, EP_RX_VALID); }

5，完成主函数的测试程序

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int main(void) {         uint8_t data[256];         uint32_t i=0;         Set_System();//系统时钟初始化         USART_Configuration();//串口1初始化         printf("x0c");printf("x0c");//超级终端清屏         printf("33[1;40;32m");//设置超级终端背景为黑色，字符为绿色         printf(" *******************************************************************************");         printf(" ************************ Copyright 2009-2012, EmbedNet ************************");         printf(" *************************** [url=http://www.embed-net.com]http://www.embed-net.com[/url] **************************");         printf(" ***************************** All Rights Reserved *****************************");         printf(" *******************************************************************************");         printf(" ");           USB_Interrupts_Config();         Set_USBClock();         USB_Init();           while(1)         {                 if(EP1_ReceivedCount > 0){                         USB_GetData(ENDP1,data,EP1_ReceivedCount);                         USB_SendData(ENDP1,data,EP1_ReceivedCount);                         printf("usb EP1 get data %d byte data ",EP1_ReceivedCount);                         for(i=0;i<EP1_ReceivedCount;i++){                                 printf("0x%02X ",data[i]);                         }                         printf(" ");                         EP1_ReceivedCount=0;                 }                 if(EP2_ReceivedCount > 0){                         USB_GetData(ENDP2,data,EP2_ReceivedCount);                         USB_SendData(ENDP2,data,EP2_ReceivedCount);                         printf("usb EP2 get data %d byte data ",EP2_ReceivedCount);                         for(i=0;i<EP2_ReceivedCount;i++){                                 printf("0x%02X ",data[i]);                         }                         printf(" ");                         EP2_ReceivedCount=0;                        }         } }

到此，STM32的程序基本上编写完成，然后编译下载程序，如果一切顺利，系统会检测到一个新的设备并试图加载对应的驱动，由于我们还没做驱动程序，所以肯定会加载驱动失败，如下图所示：
 

驱动程序生成
下面我们就利用libusb自带的inf-wizard工具生成USB驱动程序，该工具可以到本文章的附件下载，其具体过程如下：
 

运行该程序，出现下图对话框，点击“Next”；
 

出现下图对话框后选择我们需要生成驱动程序的设备；
 

这里可以写该Device Name，我们保持默认值，其他的都不需要修改；
 

点击Next后出现下图对话框，我们选择一个目录保存这个inf文件；
 

保存后的文件
 

若要立即安装驱动，可以点击下面对话框的红色框按钮；
 

Win7下可能会出现如下对话框，点击始终安装；
 

到此，USB驱动程序自动生成完毕，若安装了驱动，则在设备管理器里面会看到如下信息
 

基于libusb的上位机驱动程序编写
首先建立一个驱动程序工程，然后将libusb的库（附件有下载）添加到工程里面，编写以下几个函数
设备扫描函数，该函数用来找到插入电脑上的USB设备

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/**   * @brief  扫描设备连接数   * @param  NeedInit 是否需要初始化，第一次调用该函数需要初始化   * @retval 识别到的指定设备个数   */ int __stdcall USBScanDev(int NeedInit) {         if(NeedInit){                 usb_init(); /* initialize the library */                 usb_find_busses(); /* find all busses */                 usb_find_devices(); /* find all connected devices */         }         return scan_dev(pBoard); }

打开设备

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/**   * @brief  打开指定的USB设备   * @param  devNum        需要打开的设备号   * @retval 打开状态   */ int __stdcall USBOpenDev(int DevIndex) {         pBoardHandle[DevIndex] = open_dev(DevIndex,pBoard);         if(pBoardHandle[DevIndex]==NULL){                 return SEVERITY_ERROR;         }else{                 return SEVERITY_SUCCESS;         } }

关闭设备

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/**   * @brief  关闭指定的USB设备   * @param  devNum        需要关闭的设备号   * @retval 打开状态   */ int __stdcall USBCloseDev(int DevIndex) {         return close_dev(DevIndex,pBoardHandle); }

BULK端点写数据

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/**   * @brief  USB Bulk端点写数据   * @param  nBoardID 设备号   * @param  pipenum 端点号   * @param  sendbuffer 发送数据缓冲区   * @param  len 发送数据字节数   * @param  waittime 超时时间   * @retval 成功发送的数据字节数   */   int __stdcall USBBulkWriteData(unsigned int nBoardID,int pipenum,char *sendbuffer,int len,int waittime) {         int ret=0;         if(pBoardHandle[nBoardID] == NULL){                 return SEVERITY_ERROR;         } #ifdef TEST_SET_CONFIGURATION     if (usb_set_configuration(pBoardHandle[nBoardID], MY_CONFIG) < 0)     {         usb_close(pBoardHandle[nBoardID]);         return SEVERITY_ERROR;     } #endif   #ifdef TEST_CLAIM_INTERFACE     if (usb_claim_interface(pBoardHandle[nBoardID], 0) < 0)     {         usb_close(pBoardHandle[nBoardID]);         return SEVERITY_ERROR;     } #endif   #if TEST_ASYNC     // Running an async write test     ret = transfer_bulk_async(dev, pipenum, sendbuffer, len, waittime); #else         ret = usb_bulk_write(pBoardHandle[nBoardID], pipenum, sendbuffer, len, waittime);         /*if((len%64) == 0){                 usb_bulk_write(pBoardHandle[nBoardID], pipenum, sendbuffer, 0, waittime);         }*/ #endif #ifdef TEST_CLAIM_INTERFACE     usb_release_interface(pBoardHandle[nBoardID], 0); #endif     return ret; }

BULK端点读数据

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/**   * @brief  USB Bulk读数据   * @param  nBoardID 设备号   * @param  pipenum 端点号   * @param  readbuffer 读取数据缓冲区   * @param  len 读取数据字节数   * @param  waittime 超时时间   * @retval 读到的数据字节数   */ int __stdcall USBBulkReadData(unsigned int nBoardID,int pipenum,char *readbuffer,int len,int waittime) {         int ret=0;         if(pBoardHandle[nBoardID] == NULL){                 return SEVERITY_ERROR;         } #ifdef TEST_SET_CONFIGURATION     if (usb_set_configuration(pBoardHandle[nBoardID], MY_CONFIG) < 0)     {         usb_close(pBoardHandle[nBoardID]);         return SEVERITY_ERROR;     } #endif   #ifdef TEST_CLAIM_INTERFACE     if (usb_claim_interface(pBoardHandle[nBoardID], 0) < 0)     {         usb_close(pBoardHandle[nBoardID]);         return SEVERITY_ERROR;     } #endif   #if TEST_ASYNC     // Running an async read test     ret = transfer_bulk_async(pGinkgoBoardHandle[nBoardID], pipenum, sendbuffer, len, waittime); #else         ret = usb_bulk_read(pBoardHandle[nBoardID], pipenum, readbuffer, len, waittime); #endif #ifdef TEST_CLAIM_INTERFACE     usb_release_interface(pBoardHandle[nBoardID], 0); #endif     return ret; }

到此，PC端的驱动程序编写基本完成，下面就是驱动程序的测试，我们可以把之前这个程序生成为一个dll文件，然后单独建立一个测试工程来测试这个dll文件中的函数，测试程序如下：

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// USB_DriverTest.cpp : 定义控制台应用程序的入口点。 //   #include "stdafx.h"   #define        EP1_OUT_SIZE        64 #define        EP1_IN_SIZE        64   int _tmain(int argc, _TCHAR* argv[]) {         int DevNum;         int ret;         char WriteTestData[256]={1,2,3,4,5,6,7,8,9};         char ReadTestData[256]={0};         for(int i=0;i<256;i++){                 WriteTestData[i] = i;         }         //扫描设备连接数，需要初始化         DevNum = USBScanDev(1);         printf("设备连接数为：%d ",DevNum);         //打开设备0         ret = USBOpenDev(0);         if(ret == SEVERITY_ERROR){                 printf("打开设备失败！ ");                 return SEVERITY_ERROR;         }else{                 printf("打开设备成功！ ");         }           //端点1写数据         ret = USBBulkWriteData(0,EP1_OUT,WriteTestData,EP1_OUT_SIZE,500);         if(ret != EP1_OUT_SIZE){                 printf("端点1写数据失败！%d ",ret);                 return SEVERITY_ERROR;         }else{                 printf("端点1写数据成功！ ");         }         //端点1读数据         ret = USBBulkReadData(0,EP1_IN,ReadTestData,EP1_IN_SIZE,500);         if(ret != EP1_IN_SIZE){                 printf("端点1读数据失败！%d ",ret);                 return SEVERITY_ERROR;         }else{                 printf("端点1读数据成功！ ");                 for(int i=0;i<EP1_IN_SIZE;i++){                         printf("%02X ",ReadTestData[i]);                         if(((i+1)%16)==0){                                 printf(" ");                         }                 }                 printf(" ");         }         Sleep(100);         //端点2写数据         ret = USBBulkWriteData(0,EP2_OUT,WriteTestData+64,64,500);         if(ret != 64){                 printf("端点2写数据失败！%d ",ret);                 return SEVERITY_ERROR;         }else{                 printf("端点2写数据成功！ ");         }         //端点2读数据         ret = USBBulkReadData(0,EP2_IN,ReadTestData,64,500);         if(ret != 64){                 printf("端点2读数据失败！%d ",ret);                 return SEVERITY_ERROR;         }else{                 printf("端点2读数据成功！ ");                 for(int i=0;i<64;i++){                         printf("%02X ",ReadTestData[i]);                         if(((i+1)%16)==0){                                 printf(" ");                         }                 }                 printf(" ");         }         getchar();         return 0; }

到此，整个开发流程基本完成，下面是本套程序的测试图片

串口打印输出
 

PC端测试程序输出
 

Bus Hound抓取到的USB数据