usb-device | Experimental device-side USB framework | Change Data Capture library

I am working on an Chrome webapp that uses WebUSB running on an Android device, and am trying to understand how the connection management works.

If I am reading the spec right, if you don't already have permission to interact with the USB device, you call requestDevice to get permission from the user to trigger the initial connection workflow. You can also call getDevices() first to see if permission has already been granted, and if so can proceed from there without going through the initial connection workflow.

Assuming that's an accurate summary (please correct me if not!), then how does that connection information get stored and managed? If I go to chrome://usb-devices, I don't see the devices if they are not currently plugged in. If I go to Local Storage, I din't see anything that looks like a list of devices. Where does the permission-has-already-been-granted information live? Is it possible to forget connection information, manually or programmatically?

Thanks in advance!

I am struggling to get Windows to load the default WinUSB driver for my device. Please note that I am looking for a solution that is using BOS descriptor (and not the old 0xEE string index).

The device enumerates and Windows tells me that it is installing the device, but the WinUSB driver is not loaded. I have tried everything that I can think of, but still I can't get Windows to load the driver. I even uninstall the device and delete the USB flags in the registry whenever I re-try, but to no avail. Is there anyone who can help me to get this to work?

I don't want WebUSB capabilities or anything additional. This is a non-composite device.

This is my BOS descriptor (as sent over USB):

I am a macOS developer, and I am trying to implement this feature:

When the iPhone or iPad is connected or disconnected to the Mac, my App needs to receive a notification, and then display or remove it on NSView .

I have made the following attempts:

1. Disk Arbitration Framework - DARegisterDiskAppearedCallback & DARegisterDiskDisappearedCallback.

2. NSWorkspaceDidMountNotification & NSWorkspaceDidUnmountNotification.

3. ExternalAccessory Framework - EAAccessoryDidConnectNotification & EAAccessoryDidDisconnectNotification

Unfortunately, all three methods have failed. Methods 1 and 2 can only know the connection event of the USB flash drive, and method 3 can only be used for MFI accessories.

Could anyone tell me how to implement this feature?

I learned from the comment section of this question that maybe I should try to use IOKit to solve this problem. But after I read Apple's documentation, I was lost.

Microsoft and Qualcomm announced a new Snapdragon Developer Kit to be released this summer, 2021. Where can I find this kit? Has it been released yet?

I'm not asking for a recommendation for software. I'm asking where is this kit sold. Everything I've found indicates the Microsoft Store but I can't find it there. Qualcomm has several different Snapdragon development kits offered through various retailers but none of those are the Snapdragon Developer kit for Windows ARM. Nor does a Google search bring up anything other than either press releases or other bits of internet flotsam that is not related to this question.

Microsoft goes all-in on Windows 10 on ARM, with its target set on the M1 Macs

The forefront of those plans is a new Snapdragon Developer Kit. Microsoft says that this kit is an affordable Windows on ARM-based PC that is specially designed for developers. The kit will be available for purchase at the Microsoft Store this summer as part of a partnership between Microsoft and Qualcomm Technologies. Microsoft didn’t share specific pricing or availability, but notes it will be “cost-effective.”

Windows on Snapdragon provides a brief press release on the kit with a description but no way to buy it that I can see.

Qualcomm Enhances Support for Developers with New Snapdragon Developer Kit for Windows 10 on Arm PCs also mentions the kit but no details about where or how to purchase.

Or is there some other way of obtaining an inexpensive Windows Arm system for less than US$200?

Currently I'm planning to go with Windows 10 ARM Preview Build on a Raspberry Pi 4 and have just heard of the Snapdragon Development kit.

How to install Windows 10 on Raspberry Pi 4

How to Install Windows 10 on Raspberry Pi? (Illustrated Guide)

Booting my Raspberry Pi 4 from a USB device

I'm working on extending a receipt printing Serial Port (COM) interface for a thermal receipt printer to use a USB interface without needing a Virtual Serial Port. I have a working prototype that will enumerate over the attached USB devices, locate the USB path for a device with a specific vendor id and product id, and open a connection to the device using CreateFile().

The existing Serial Port code uses the Windows API wrapped in a set of functions. The approach I'm taking is to add additional code using the same set of functions but that depend on a USB connection rather than a Serial Port connection. I have previously used the same approach to allow the use of a kitchen printer over either a Serial Port or over a WiFi/LAN connection with minimal changes to existing code successfully.

Unfortunately the existing code that uses the function library depends on the functions to use ReadFile() with a time out specified so that if the thermal printer does not respond to a status request within a reasonable time, the application can mark it as down and allow operations to continue or to use a backup or secondary printer.

How do I specify a time out for a ReadFile() on a file handle from CreateFile() that opens a connection to a communications devices using a USB pathname?

A consideration is this is multi-threaded code used for more than one serial communications device (receipt printer, kitchen printer, scale, etc.) however a thread will have exclusive access to a particular device (kitchen printing functionality opens serial port to kitchen printer only, scale reading functionality opens serial port to scale only, etc.).

In the existing Serial Port code, the function used to set timeouts, SetCommTimeouts(), for a Serial Port connection opened with CreateFile() does not work for a USB connection opened with CreateFile() (see SetupComm, SetCommState, SetCommTimeouts fail with USB device). This means some other mechanism is needed to provide a way to allow for an I/O failure due to a time out when using a USB device pathname.

We are using the following code segment to open a Serial Port, whether to a hardware COM port or a Virtual Serial Port emulating a hardware COM port:

This question is not duplicate for Programmatically obtaining the vendor ID, product ID of a USB device on Android platform

Because I am not trying to get the VendorID and ProductID for the attached device, I am trying to get the PID and VID for the Android phone to do something with them, how to get them. Unfortunately the class UsbDevice represents an attached UsbDevice which is not my case.

I have a store which contains an object, I have a viewmodel with this store and I have a grid with store bound to this viewmodel store.

Example: (In my case object in much more complex)

I tried to connect USB devices in uwp according to the instructions in MSDN, but I couldn't connect to usb devices and always getting null from UsbDevice.FromIdAsync (). I had seen may questions and answers regarding this issue here here

But nothing solved my issue. Any help would be appreciated.

these are the code snippet am trying. the same code snippet is working with .Net standard applications. But not working with UWP.

I am trying to open a webcam for video streaming on my raspberry pi 4 with OpenCV 4.

The VideoCapture constructor in OpenCV takes the index/address of the location of the device. Using 'lsusb' I get this: