The device descriptor describes general information about the device. The key fields in this descriptor that define this device as composite are the device class, subclass, and protocol. These three fields are not filled with zeros as is usually the case with composite devices because the configuration descriptor contains an IAD descriptor. Figure 1 USB Standard Device Descriptor Enumeration of Interface Collections on USB Devices with IADs If a USB composite device has an interface association descriptor (IAD) in its firmware, Windows enumerates interface collections as though each collection were a single device and assigns a single physical device object (PDO) to each interface collection and associates hardware and compatible identifiers (IDs) with the PDO.
An interface descriptor never includes Endpoint 0 in the numbering of endpoints. If an interface uses only Endpoint 0, then the field bNumEndpoints must be set to zero. If no class type has been selected for the device, then none of the standard USB drivers is loaded, and the developer has to provide its own device driver.
5 Building a USB composite device The Atmel AVR Software Framework (ASF) provides many USB Interface modules which can be added on a USB composite device. These modules are available in Atmel AVR Studio 5 and can be imported in an AVR Studio 5 project. This section describes how to add a USB composite device in an existing project: 1. USB Devices that support both full and high speed modes must have a device_qualifier Descriptor. When the USB device switches its speed mode, values in some fields get changed in device descriptor. The device_qualifier descriptor provides information only about those field values that get changed when device switches to an alternate speed mode. Grid+ Issue and Fix (For "Unknown USB Device(Device Descriptor Failed)") Like many of you, my Grid+ always shows up as "Unknown USB Device(Device Descriptor Failed)" in my Device Manager. After hours of searching, troubleshooting, and yelling, I found a workaround that works.
Every Universal Serial Bus (USB) device must be able to provide a single device descriptor that contains relevant information about the device. The USB_DEVICE_DESCRIPTOR structure describes a device descriptor. Windows uses that information to derive various sets of information. You may try the steps listed below and check if it works: Right click the Windows icon on the taskbar and choose ‘ Device Manager’. Expand ‘ Universal Serial Bus Controllers’. Right click ‘ USB Host Controllers’ and uninstall. Restart the computer and check if the issue persists. IOCTL_INTERNAL_USB_SUBMIT_URB to get USB configuration descriptors. When I pass the URB to composite devices driver usbccgp.sys, I can get USB configuration descriptor back successfully. However, if I pass the URB to USB-defined mass storage device class driver usbstor.sys, I always get STATUS_INVALID_DEVICE_REQUEST status return.
USB devices can only have one device descriptor. The device descriptor includes information such as what USB revision the device complies to, the Product and Vendor IDs used to load the appropriate drivers and the number of possible configurations the device can have. USB Service Implementation: usb4java Implementation version: 1.2.0 Service API version: 1.0.2 usb4java root hub 1.0.0 Device Descriptor: bLength 18 bDescriptorType 1 bcdUSB 1.01 bDeviceClass 9 Hub bDeviceSubClass 0 bDeviceProtocol 0 bMaxPacketSize0 8 idVendor 0xffff idProduct 0xffff bcdDevice 0.00 iManufacturer 1 iProduct 2 iSerial 3 bNumConfigurations 1 Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 18 bNumInterfaces 1 bConfigurationValue 1 iConfiguration 0 bmAttributes ... Since device descriptor and configuration descriptor are similar for any kind of device, only some other descriptors are described in this section. Following discussion is based on the audio_speaker demo provided with the USB stack; the descriptors are defined in usb_descriptor.c and comply with the USB Audio Device Class Specification 2.0.
Jul 10, 2010 · As everybody knows Windows CE 6.0 supports USB functional composite driver to load multiple client driver simultaneously. Normally we used to load the functional device classes having single interface descriptor. The Device Descriptor (USB_DEVICE_DESCRIPTOR) is the root of the descriptor tree and contains basic device information. The unique numbers, idVendor and idProduct , identify the connected device. The Windows operating system uses these numbers to determine which device driver must be loaded. Oct 01, 2001 · If a program currently has an open handle to the device, we only null the usb_device structure in our local structure, as it has now gone away. For every read, write, release and other functions that expect a device to be present, the driver first checks to see if this usb_device structure is still present.
STM32F4 USB Composite CDC + MSC. I'm in the process of building a USB composite CDC + MSC device on the STM32F4 Discovery board but am having trouble getting windows to recognise it. Using USBlyzer all the descriptor info seems ok but windows will only recognise the CDC (virtual com port). Sep 30, 2010 · For USB composite devices with functions which use these in-box drivers, the device vendor may be able to work around the problem by reconfiguring their device so that the Interface(s) for the affected function appear(s) first in the USB Composite Device's Configuration Descriptor, or by implementing the device as a USB Compound device, as described above.
I couldnt find any info about this. When you get a red X during the setup, is it a cable issue? Or a "not enough power" issue? I tried 4 different cable types (not the anker), and all give me a red X when trying to setup the quest. When the USB device is a composite device, the extended configuration descriptor includes function information corresponding to a plurality of sub-devices. Each function comprises one or more interfaces.
These devices primarily act as USB devices when plugged in, to provide functions such as MTP, PTP and ADB to the host computer. Setting it Up You can do all of this without a serial cable, but having one really helps because it’s a low-level (and bi-directional) means of communicating with the Pi Zero.
Nov 25, 2013 · USB devices are made to be backwards compatible. Much like USB 2.0 devices work in USB 1.0, USB 3.0 devices work in USB 2.0. I would recommend getting a USB 3.0 device over a 2.0 device because then any newer device or computer that is compatible with USB3.0 would be able to take advantage of the higher speed. xiaohorse New Member posted November 06, 2009 12:01 AM I implemented my usb device as two com ports on PC (xp sp3) using IAD successfully. Now the two com ports works well respectively, ho