USB枚举过程分析
21 Dec 2017
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软件:Keil4,STM32CubeMX,Device Monitoring Studio,Qt5.9;
硬件:USBSTM32(自制)
1.USB设备的启动流程:
一旦有设备连接到主机,主机就会发送一系列Requests(请求)到设备所挂载的hub上面,hub收到请求之后,就会建立起一条连接Host(主机)和Device(设备)的通信通道,然后Host再以Controll Transfer(控制传输)的方式,通过端点0(Ep0)对设备发送各种请求,设备根据主机的请求回复对应的信息(这个过程称为枚举操作).因此,所有的USB设备都必须支持StandardRequests,ControlTransfer和Ep0,才能完成设备的枚举操作.详细的枚举过程参考blog
1.用户把USB设备插入USB端口;
2.Hub检测它各个端口数据线上(D+/D-)的电压.
3.Hub把新设备连接事件报告主机,主机发送Get_Port_Status请求给Hub,要求Hub报告改变的含义.
4.Hub根据电压来判断设
5.HUb发送Set_Port_Feature请求,通过数据线,把D+/D-全部拉低,持续10ms.以此来进行USB设备的复位.
6.Host检测所连接的全速设备是否支持高速模式.
7.Hub建立设备和主机之前的信息通道(此时,USB设备的默认地址和端点号均为0).
8.主机发送Get_Descriptor请求获得默认管道的最大包长度.
9.主机给设备分配一个地址.
10.主机获取设备的信息-10.1 设备描述符 10.2配置描述符 10.3 配置集合(配置描述符,接口描述符,断电描述符)
2.修改由Stm32CubeMX生成的工程文件
2.1 修改usbd_desc.c
修改usbd_desc.c中的设备描述符USBD_HS_DeviceDesc
__ALIGN_BEGIN uint8_t USBD_HS_DeviceDesc[USB_LEN_DEV_DESC] __ALIGN_END =
{
0x12, /*bLength */
USB_DESC_TYPE_DEVICE, /*bDescriptorType*/
#if (USBD_LPM_ENABLED == 1)
0x01, /*bcdUSB */ /* changed to USB version 2.01
in order to support LPM L1 suspend
resume test of USBCV3.0*/
#else
0x00, /* bcdUSB */
#endif
0x02,
0x02, /*bDeviceClass*/
0x02, /*bDeviceSubClass*/
0x00, /*bDeviceProtocol*/
USB_MAX_EP0_SIZE, /*bMaxPacketSize*/
LOBYTE(USBD_VID), /*idVendor*/
HIBYTE(USBD_VID), /*idVendor*/
LOBYTE(USBD_PID_HS), /*idVendor*/
HIBYTE(USBD_PID_HS), /*idVendor*/
0x00, /*bcdDevice rel. 2.00*/
0x02,
USBD_IDX_MFC_STR, /*Index of manufacturer string*/
USBD_IDX_PRODUCT_STR, /*Index of product string*/
USBD_IDX_SERIAL_STR, /*Index of serial number string*/
USBD_MAX_NUM_CONFIGURATION /*bNumConfigurations*/
} ;
修改为:
__ALIGN_BEGIN uint8_t USBD_HS_DeviceDesc[USB_LEN_DEV_DESC] __ALIGN_END =
{
0x12, /*bLength */
USB_DESC_TYPE_DEVICE, /*bDescriptorType*/
#if (USBD_LPM_ENABLED == 1)
0x01, /*bcdUSB */ /* changed to USB version 2.01
in order to support LPM L1 suspend
resume test of USBCV3.0*/
#else
0x00, /* bcdUSB */
#endif
0x02,
0x00, /*bDeviceClass*/
0x00, /*bDeviceSubClass*/
0x00, /*bDeviceProtocol*/
USB_MAX_EP0_SIZE, /*bMaxPacketSize*/
LOBYTE(USBD_VID), /*idVendor*/
HIBYTE(USBD_VID), /*idVendor*/
LOBYTE(USBD_PID_HS), /*idVendor*/
HIBYTE(USBD_PID_HS), /*idVendor*/
0x00, /*bcdDevice rel. 2.00*/
0x02,
USBD_IDX_MFC_STR, /*Index of manufacturer string*/
USBD_IDX_PRODUCT_STR, /*Index of product string*/
USBD_IDX_SERIAL_STR, /*Index of serial number string*/
USBD_MAX_NUM_CONFIGURATION /*bNumConfigurations*/
} ;
2.2 修改usbd_cdc.c
修改usbd_cdc.c里面的配置描述符USBD_CDC_CfgHSDesc,USBD_CDC_CfgFSDesc,USBD_CDC_OtherSpeedCfgDesc,并把USB_CDC_CONFIG_DESC_SIZ的长度改成32(按照实际)
/* USB CDC device Configuration Descriptor */
__ALIGN_BEGIN uint8_t USBD_CDC_CfgHSDesc[USB_CDC_CONFIG_DESC_SIZ] __ALIGN_END =
{
/*Configuration Descriptor*/
0x09, /* bLength: Configuration Descriptor size */
USB_DESC_TYPE_CONFIGURATION, /* bDescriptorType: Configuration */
USB_CDC_CONFIG_DESC_SIZ, /* wTotalLength:no of returned bytes */
0x00,
0x02, /* bNumInterfaces: 2 interface */
0x01, /* bConfigurationValue: Configuration value */
0x00, /* iConfiguration: Index of string descriptor describing the configuration */
0xC0, /* bmAttributes: self powered */
0x32, /* MaxPower 0 mA */
/*---------------------------------------------------------------------------*/
/*Interface Descriptor */
0x09, /* bLength: Interface Descriptor size */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType: Interface */
/* Interface descriptor type */
0x00, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x01, /* bNumEndpoints: One endpoints used */
0x02, /* bInterfaceClass: Communication Interface Class */
0x02, /* bInterfaceSubClass: Abstract Control Model */
0x01, /* bInterfaceProtocol: Common AT commands */
0x00, /* iInterface: */
/*Header Functional Descriptor*/
0x05, /* bLength: Endpoint Descriptor size */
0x24, /* bDescriptorType: CS_INTERFACE */
0x00, /* bDescriptorSubtype: Header Func Desc */
0x10, /* bcdCDC: spec release number */
0x01,
/*Call Management Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x01, /* bDescriptorSubtype: Call Management Func Desc */
0x00, /* bmCapabilities: D0+D1 */
0x01, /* bDataInterface: 1 */
/*ACM Functional Descriptor*/
0x04, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x02, /* bDescriptorSubtype: Abstract Control Management desc */
0x02, /* bmCapabilities */
/*Union Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x06, /* bDescriptorSubtype: Union func desc */
0x00, /* bMasterInterface: Communication class interface */
0x01, /* bSlaveInterface0: Data Class Interface */
/*Endpoint 2 Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_CMD_EP, /* bEndpointAddress */
0x03, /* bmAttributes: Interrupt */
LOBYTE(CDC_CMD_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_CMD_PACKET_SIZE),
0x10, /* bInterval: */
/*---------------------------------------------------------------------------*/
/*Data class interface descriptor*/
0x09, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType: */
0x01, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x02, /* bNumEndpoints: Two endpoints used */
0x0A, /* bInterfaceClass: CDC */
0x00, /* bInterfaceSubClass: */
0x00, /* bInterfaceProtocol: */
0x00, /* iInterface: */
/*Endpoint OUT Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_OUT_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
LOBYTE(CDC_DATA_HS_MAX_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_DATA_HS_MAX_PACKET_SIZE),
0x00, /* bInterval: ignore for Bulk transfer */
/*Endpoint IN Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_IN_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
LOBYTE(CDC_DATA_HS_MAX_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_DATA_HS_MAX_PACKET_SIZE),
0x00 /* bInterval: ignore for Bulk transfer */
} ;
/* USB CDC device Configuration Descriptor */
__ALIGN_BEGIN uint8_t USBD_CDC_CfgFSDesc[USB_CDC_CONFIG_DESC_SIZ] __ALIGN_END =
{
/*Configuration Descriptor*/
0x09, /* bLength: Configuration Descriptor size */
USB_DESC_TYPE_CONFIGURATION, /* bDescriptorType: Configuration */
USB_CDC_CONFIG_DESC_SIZ, /* wTotalLength:no of returned bytes */
0x00,
0x02, /* bNumInterfaces: 2 interface */
0x01, /* bConfigurationValue: Configuration value */
0x00, /* iConfiguration: Index of string descriptor describing the configuration */
0xC0, /* bmAttributes: self powered */
0x32, /* MaxPower 0 mA */
/*---------------------------------------------------------------------------*/
/*Interface Descriptor */
0x09, /* bLength: Interface Descriptor size */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType: Interface */
/* Interface descriptor type */
0x00, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x01, /* bNumEndpoints: One endpoints used */
0x02, /* bInterfaceClass: Communication Interface Class */
0x02, /* bInterfaceSubClass: Abstract Control Model */
0x01, /* bInterfaceProtocol: Common AT commands */
0x00, /* iInterface: */
/*Header Functional Descriptor*/
0x05, /* bLength: Endpoint Descriptor size */
0x24, /* bDescriptorType: CS_INTERFACE */
0x00, /* bDescriptorSubtype: Header Func Desc */
0x10, /* bcdCDC: spec release number */
0x01,
/*Call Management Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x01, /* bDescriptorSubtype: Call Management Func Desc */
0x00, /* bmCapabilities: D0+D1 */
0x01, /* bDataInterface: 1 */
/*ACM Functional Descriptor*/
0x04, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x02, /* bDescriptorSubtype: Abstract Control Management desc */
0x02, /* bmCapabilities */
/*Union Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x06, /* bDescriptorSubtype: Union func desc */
0x00, /* bMasterInterface: Communication class interface */
0x01, /* bSlaveInterface0: Data Class Interface */
/*Endpoint 2 Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_CMD_EP, /* bEndpointAddress */
0x03, /* bmAttributes: Interrupt */
LOBYTE(CDC_CMD_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_CMD_PACKET_SIZE),
0x10, /* bInterval: */
/*---------------------------------------------------------------------------*/
/*Data class interface descriptor*/
0x09, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType: */
0x01, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x02, /* bNumEndpoints: Two endpoints used */
0x0A, /* bInterfaceClass: CDC */
0x00, /* bInterfaceSubClass: */
0x00, /* bInterfaceProtocol: */
0x00, /* iInterface: */
/*Endpoint OUT Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_OUT_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
LOBYTE(CDC_DATA_FS_MAX_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_DATA_FS_MAX_PACKET_SIZE),
0x00, /* bInterval: ignore for Bulk transfer */
/*Endpoint IN Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_IN_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
LOBYTE(CDC_DATA_FS_MAX_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_DATA_FS_MAX_PACKET_SIZE),
0x00 /* bInterval: ignore for Bulk transfer */
} ;
__ALIGN_BEGIN uint8_t USBD_CDC_OtherSpeedCfgDesc[USB_CDC_CONFIG_DESC_SIZ] __ALIGN_END =
{
0x09, /* bLength: Configuation Descriptor size */
USB_DESC_TYPE_OTHER_SPEED_CONFIGURATION,
USB_CDC_CONFIG_DESC_SIZ,
0x00,
0x02, /* bNumInterfaces: 2 interfaces */
0x01, /* bConfigurationValue: */
0x04, /* iConfiguration: */
0xC0, /* bmAttributes: */
0x32, /* MaxPower 100 mA */
/*Interface Descriptor */
0x09, /* bLength: Interface Descriptor size */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType: Interface */
/* Interface descriptor type */
0x00, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x01, /* bNumEndpoints: One endpoints used */
0x02, /* bInterfaceClass: Communication Interface Class */
0x02, /* bInterfaceSubClass: Abstract Control Model */
0x01, /* bInterfaceProtocol: Common AT commands */
0x00, /* iInterface: */
/*Header Functional Descriptor*/
0x05, /* bLength: Endpoint Descriptor size */
0x24, /* bDescriptorType: CS_INTERFACE */
0x00, /* bDescriptorSubtype: Header Func Desc */
0x10, /* bcdCDC: spec release number */
0x01,
/*Call Management Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x01, /* bDescriptorSubtype: Call Management Func Desc */
0x00, /* bmCapabilities: D0+D1 */
0x01, /* bDataInterface: 1 */
/*ACM Functional Descriptor*/
0x04, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x02, /* bDescriptorSubtype: Abstract Control Management desc */
0x02, /* bmCapabilities */
/*Union Functional Descriptor*/
0x05, /* bFunctionLength */
0x24, /* bDescriptorType: CS_INTERFACE */
0x06, /* bDescriptorSubtype: Union func desc */
0x00, /* bMasterInterface: Communication class interface */
0x01, /* bSlaveInterface0: Data Class Interface */
/*Endpoint 2 Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT , /* bDescriptorType: Endpoint */
CDC_CMD_EP, /* bEndpointAddress */
0x03, /* bmAttributes: Interrupt */
LOBYTE(CDC_CMD_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_CMD_PACKET_SIZE),
0xFF, /* bInterval: */
/*---------------------------------------------------------------------------*/
/*Data class interface descriptor*/
0x09, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType: */
0x01, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x02, /* bNumEndpoints: Two endpoints used */
0x0A, /* bInterfaceClass: CDC */
0x00, /* bInterfaceSubClass: */
0x00, /* bInterfaceProtocol: */
0x00, /* iInterface: */
/*Endpoint OUT Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_OUT_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
0x40, /* wMaxPacketSize: */
0x00,
0x00, /* bInterval: ignore for Bulk transfer */
/*Endpoint IN Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_IN_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
0x40, /* wMaxPacketSize: */
0x00,
0x00 /* bInterval */
};
修改为:
/* USB CDC device Configuration Descriptor */
__ALIGN_BEGIN uint8_t USBD_CDC_CfgHSDesc[USB_CDC_CONFIG_DESC_SIZ] __ALIGN_END =
{
/*Configuration Descriptor*/
0x09, /* bLength: Configuration Descriptor size */
USB_DESC_TYPE_CONFIGURATION, /* bDescriptorType: Configuration */
USB_CDC_CONFIG_DESC_SIZ, /* wTotalLength:no of returned bytes */
0x00,
0x01, /* bNumInterfaces: 1 interface */
0x01, /* bConfigurationValue: Configuration value */
0x00, /* iConfiguration: Index of string descriptor describing the configuration */
0xE0, /* bmAttributes: self powered */
0xFA, /* MaxPower 500 mA */
/*---------------------------------------------------------------------------*/
/*Interface Descriptor */ //接口描述符
0x09, /* bLength: Interface Descriptor size */
USB_DESC_TYPE_INTERFACE, /* bDescriptorType: Interface */
/* Interface descriptor type */
0x00, /* bInterfaceNumber: Number of Interface */
0x00, /* bAlternateSetting: Alternate setting */
0x02, /* bNumEndpoints: One endpoints used */
0xDC, /* bInterfaceClass: Communication Interface Class */
0xA0, /* bInterfaceSubClass: Abstract Control Model */
0xB0, /* bInterfaceProtocol: Common AT commands */
0x00, /* iInterface: */
/*Endpoint OUT Descriptor*/ //端点描述符
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_OUT_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
LOBYTE(CDC_DATA_HS_MAX_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_DATA_HS_MAX_PACKET_SIZE),
0x00, /* bInterval: ignore for Bulk transfer */
/*Endpoint IN Descriptor*/
0x07, /* bLength: Endpoint Descriptor size */
USB_DESC_TYPE_ENDPOINT, /* bDescriptorType: Endpoint */
CDC_IN_EP, /* bEndpointAddress */
0x02, /* bmAttributes: Bulk */
LOBYTE(CDC_DATA_HS_MAX_PACKET_SIZE), /* wMaxPacketSize: */
HIBYTE(CDC_DATA_HS_MAX_PACKET_SIZE),
0x00 /* bInterval: ignore for Bulk transfer */
} ;
2.3 修改其他配置符-在CubeMx里面配置,这里无须再配置,详见->[CubeMx]Device Descriptor
2.4 根据端点缓冲区大小配置端点缓冲地址-在CubeMx里面配置,这里无需再配
2.5 用Device Monitoring Studio查看设备描述符和配置描述符信息是否正确了.
2.6 编程,与设备进行通讯
参考资料:
[1]通过STM32CUbeMX建立USB HID的双向通讯实验成功
[2]用STM32Cube简单实现自定义USB HID通信
[3]STM32 USB HID 自定义设备 bulk 传输
[4]飞鸿踏雪
[5]纬图科技