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If drivers were not downloaded automatically by Windows Update, use Device Manager to refresh the driver from Windows Update, or contact the device manufacturer. I’m Moli, your virtual agent. I can help with Moto phone issues. To verify that your driver is working, you should see a difference in the following pictures after plugging the CH340 to a USB port. To check that the CH340 enumerates to a COM port, you can open the device manager. You can click the Start or ⊞ (Windows) button and type 'device manager to quickly search for the application. Improvements and fixes. This update includes a fix for an incorrect device driver (“Microsoft – WPD – 2/22/2016 12:00:00 AM - 5.2.5326.4762”) that was released by a third-party on March 8, 2017 that affected a small group of users with USB connected phones or other media devices that rely on Media Transfer Protocol (MTP). Thus, you should try to reinstall the USB device driver. Connect the USB flash drive to the PC. Navigate to 'Control Panel' 'System' ‘’Device Manager' 'Disk drivers'. Find and select your USB device, right-click and first choose 'Uninstall' and then choose 'Scan for hardware changes' to refresh the drivers.

Universal Serial Bus (USB) provides an expandable, hot-pluggable Plug and Play serial interface that ensures a standard, low-cost connection for peripheral devices such as keyboards, mice, joysticks, printers, scanners, storage devices, modems, and video conferencing cameras. Migration to USB is recommended for all peripheral devices that use legacy ports such as PS/2, serial, and parallel ports.

The USB-IF is a Special Interest Groups (SIGs) that maintains the Official USB Specification, test specifications and tools.

Windows operating systems include native support for USB host controllers, hubs, and devices and systems that comply with the official USB specification. Windows also provides programming interfaces that you can use to develop device drivers and applications that communicate with a USB device.

USB in WindowsWindows 10: What's new for USB

Overview of new features and improvements in USB in Windows 10.

USB FAQ

Frequently asked questions from driver developers about the USB stack and features that are supported in USB.

Microsoft OS Descriptors for USB Devices

Windows defines MS OS descriptors that allows better enumeration when connected to system running Windows operating system

Microsoft-provided USB driversUSB device-side drivers in Windows

A set of drivers for handling common function logic for USB devices.

USB host-side drivers in Windows

Microsoft provides a core stack of drivers that interoperate with devices that are connected to EHCI and xHCI controllers.

USB-IF device class drivers

Windows provides in-box device class drivers for many USB-IF approved device classes, audio, mass storage, and so on.

USB generic function driver–WinUSB

Windows provides Winusb.sys that can be loaded as a function driver for a custom device and a function of a composite device.

USB generic parent driver for composite devices–Usbccgp

Parent driver for USB devices with multiple functions. Usbccgp creates physical device objects (PDOs) for each of those functions. Those individual PDOs are managed by their respective USB function drivers, which could be the Winusb.sys driver or a USB device class driver.

WDF extension for developing USB drivers

USB connector manager class extension (UcmCx) reference
USB host controller (UCX) reference
USB function class extension (UFX) reference

Testing USB devices with Windows

Get information about the tools that you can use to test your USB hardware or software, capture traces of operations and other system events, and observe how the USB driver stack responds to a request sent by a client driver or an application.

Read an overview of tests in the Hardware Certification Kit that enable hardware vendors and device manufacturers to prepare their USB devices and host controllers for Windows Hardware Certification submission.

Other Resources for USB

Official USB Specification

Provides complete technical details for the USB protocol.

Microsoft Windows USB Core Team Blog

Check out posts written by the Microsoft USB Team. The blog focuses on the Windows USB driver stack that works with various USB Host controllers and USB hubs found in Windows PC. A useful resource for USB client driver developers and USB hardware designers understand the driver stack implementation, resolve common issues, and explain how to use tools for gathering traces and log files.

OSR Online Lists - ntdev

Discussion list managed by OSR Online for kernel-mode driver developers.

Windows Dev-Center for Hardware Development

Miscellaneous resources based on frequently asked questions from developers who are new to developing USB devices and drivers that work with Windows operating systems.

USB-related videos

UWP apps for USB devicesUnderstanding USB 3.0 in Windows 8Building great USB 3.0 devicesUSB Debugging Innovations in Windows 8 (Part I, II, & III)

USB hardware for learning

MUTT devices

MUTT and SuperMUTT devices and the accompanying software package are integrated into the HCK suite of USB tests. They provide automated testing that can be used during the development cycle of USB controllers, devices and systems, especially stress testing.

OSR USB FX2 Learning Kit

If you are new to USB driver development. The kit is the most suitable to study USB samples included in this documentation set. You can get the learning kit from OSR Online Store.

Write a USB client driver (KMDF, UMDF)

Introduces you to USB driver development. Provides information about choosing the most appropriate model for providing a USB driver for your device. This section also includes tutorials about writing your first user-mode and kernel-mode USB drivers by using the USB templates included with Microsoft Visual Studio.

Write a USB host controller driver

If you are developing an xHCI host controller that is not compliant with the specification or developing a custom non-xHCI hardware (such as a virtual host controller), you can write a host controller driver that communicates with UCX. For example, consider a wireless dock that supports USB devices. The PC communicates with USB devices through the wireless dock by using USB over TCP as a transport.

USB host controller (UCX) reference

Write a function controller driver for a USB device

You can develop a controller driver that handles all USB data transfers and commands sent by the host to the device. This driver communicates with the Microsoft-provided USB function controller extension (UFX).

USB function class extension (UFX) reference

Write a USB Type-C connector driver

Windows 10 introduces support for the new USB connector: USB Type-C. You can write a driver for the connector that communicates with the Microsoft-provided class extension module: UcmCx to handle scenarios related to Type-C connectors such as, which ports support Type-C, which ports support power delivery.

USB connector manager class extension (UcmCx) reference

Write a USB dual-role controller driver

USB Dual Role controllers are now supported in Windows 10. Windows includes in-box client drivers for ChipIdea and Synopsys controllers. For other controllers, Microsoft provides a set of programming interfaces that allow the dual-role class extension (UrsCx) and its client driver to communicate with each other to handle the role-switching capability of a dual-role controller.

For more information about this feature, see:

USB dual-role controller driver programming reference

Write a USB driver for emulated devices

Windows 10 introduces support for emulated devices. Now you can develop an emulated Universal Serial Bus (USB) host controller driver and a connected virtual USB device. Both components are combined into a single KMDF driver that communicates with the Microsoft-provided USB device emulation class extension (UdeCx).

Emulated USB host controller driver programming reference

Write a UWP app

Provides step-by-step instructions about implementing USB features in a UWP app. To write such an app for a USB device you need Visual Studio and Microsoft Windows Software Development Kit (SDK) .

Write a Wi

Drivers Intellitools USB Devices