[mw_shl_code=c,true] case HOST_ENUMERATION: /* Check for enumeration status */ if ( USBH_HandleEnum(pdev , phost) == USBH_OK) { /* The function shall return USBH_OK when full enumeration is complete */ /* user callback for end of device basic enumeration */ phost->usr_cb->EnumerationDone(); phost->gState = HOST_USR_INPUT; } break;[/mw_shl_code]
[mw_shl_code=c,true] case ENUM_IDLE: /* Get Device Desc for only 1st 8 bytes : To get EP0 MaxPacketSize */ if ( USBH_Get_DevDesc(pdev , phost, 8) == USBH_OK) { phost->Control.ep0size = phost->device_prop.Dev_Desc.bMaxPacketSize; /* Issue Reset */ HCD_ResetPort(pdev); phost->EnumState = ENUM_GET_FULL_DEV_DESC; /* modify control channels configuration for MaxPacket size */ USBH_Modify_Channel (pdev, phost->Control.hc_num_out, 0, 0, 0, phost->Control.ep0size); USBH_Modify_Channel (pdev, phost->Control.hc_num_in, 0, 0, 0, phost->Control.ep0size); } break;[/mw_shl_code]
[mw_shl_code=c,true]USBH_Status USBH_Get_DevDesc(USB_OTG_CORE_HANDLE *pdev, USBH_HOST *phost, uint8_t length) { USBH_Status status; if((status = USBH_GetDescriptor(pdev, phost, USB_REQ_RECIPIENT_DEVICE | USB_REQ_TYPE_STANDARD, USB_DESC_DEVICE, pdev->host.Rx_Buffer, length)) == USBH_OK) { /* Commands successfully sent and Response Received */ USBH_ParseDevDesc(&phost->device_prop.Dev_Desc, pdev->host.Rx_Buffer, length); } return status; }[/mw_shl_code]

[mw_shl_code=c,true]typedef enum { USBH_OK = 0, USBH_BUSY, USBH_FAIL, USBH_NOT_SUPPORTED, USBH_UNRECOVERED_ERROR, USBH_ERROR_SPEED_UNKNOWN, USBH_APPLY_DEINIT }USBH_Status;[/mw_shl_code]

在USBH_Process函数中发现主要是枚举的这个if条件满足不了，一步步仿真切入分析，发现主要是这个if进不了，status为1，即始终是USBH_BUSY。


请问谁知道这是怎么回事？