用STM32CubeMx5.3版本生�?的USB HOST �?始化U盘一直�?�在HOST_DEV_WAIT_FOR_ATTACHMENT这个环节，请问是怎么回事

[新药.970]

switch (phost->gState)
 {
 case HOST_IDLE :
 
 if (phost->device.is_connected)
 {
 USBH_UsrLog("USB Device Connected");
 
 /* Wait for 200 ms after connection */
 phost->gState = HOST_DEV_WAIT_FOR_ATTACHMENT;
 USBH_Delay(200U);
 USBH_LL_ResetPort(phost);
 
#if (USBH_USE_OS == 1U)
 phost->os_msg = (uint32_t)USBH_PORT_EVENT;
#if (osCMSIS < 0x20000U)
 (void)osMessagePut(phost->os_event, phost->os_msg, 0U);
#else
 (void)osMessageQueuePut(phost->os_event, &phost->os_msg, 0U, NULL);
#endif
#endif
 }
 break;
 
 case HOST_DEV_WAIT_FOR_ATTACHMENT: /* Wait for Port Enabled */
 
 if (phost->device.PortEnabled == 1U)
 {
 USBH_UsrLog("USB Device Reset Completed");
 phost->gState = HOST_DEV_ATTACHED;
 }
 break;
 
 case HOST_DEV_ATTACHED :
 
 if (phost->pUser != NULL)
 {
 phost->pUser(phost, HOST_USER_CONNECTION);
 }
 
 /* Wait for 100 ms after Reset */
 USBH_Delay(100U);
 
 phost->device.speed = USBH_LL_GetSpeed(phost);
 
 phost->gState = HOST_ENUMERATION;
 
 phost->Control.pipe_out = USBH_AllocPipe(phost, 0x00U);
 phost->Control.pipe_in = USBH_AllocPipe(phost, 0x80U);
 
 
 /* Open Control pipes */
 USBH_OpenPipe(phost,
 phost->Control.pipe_in,
 0x80U,
 phost->device.address,
 phost->device.speed,
 USBH_EP_CONTROL,
 (uint16_t)phost->Control.pipe_size);
 
 /* Open Control pipes */
 USBH_OpenPipe(phost,
 phost->Control.pipe_out,
 0x00U,
 phost->device.address,
 phost->device.speed,
 USBH_EP_CONTROL,
 (uint16_t)phost->Control.pipe_size);
 
#if (USBH_USE_OS == 1U)
 phost->os_msg = (uint32_t)USBH_PORT_EVENT;
#if (osCMSIS < 0x20000U)
 (void)osMessagePut(phost->os_event, phost->os_msg, 0U);
#else
 (void)osMessageQueuePut(phost->os_event, &phost->os_msg, 0U, NULL);
#endif
#endif
 break;
 
 case HOST_ENUMERATION:
 /* Check for enumeration status */
 if (USBH_HandleEnum(phost) == USBH_OK)
 {
 /* The function shall return USBH_OK when full enumeration is complete */
 USBH_UsrLog("Enumeration done.");
 
 phost->device.current_interface = 0U;
 
 if (phost->device.DevDesc.bNumConfigurations == 1U)
 {
 USBH_UsrLog("This device has only 1 configuration.");
 phost->gState = HOST_SET_CONFIGURATION;
 
 }
 else
 {
 phost->gState = HOST_INPUT;
 }
 
 }
 break;