What is USB class and SubClass?
USB defines class code information that is used to identify a device’s functionality and to nominally load a device driver based on that functionality. The information is contained in three bytes with the names Base Class, SubClass, and Protocol. That terminology is not used in the USB Specification).
What is USB Class driver?
Class drivers are very often used with USB based devices, which share the essential USB protocol in common, and devices with similar functionality can easily adopt common protocols.
What is the USB protocol?
Universal Serial Bus
The USB protocol, also known as Universal Serial Bus, was first created and introduced in 1996 as a way to institutionalize a more widespread, uniform cable and connector that could be used across a multitude of different devices.
What is USB CDC device?
USB communications device class (or USB CDC class) is a composite Universal Serial Bus device class. The communications device class is used for computer networking devices akin to a network card, providing an interface for transmitting Ethernet or ATM frames onto some physical media.
How does USB protocol work?
USB device communication is done through pipes. These pipes are a connection pathway from the host controller to an addressable buffer called an endpoint. An endpoint stores received data from the host and holds the data that is waiting to transmit to the host.
What does class compliant USB mean?
Most USB audio and MIDI computer peripherals are “Class Compliant” devices. This means that to communicate with the computer, they use drivers that are built right into the host computer’s operating system. These drivers are written by Microsoft (or Apple for Mac OS X), and come pre-installed on all computers.
What does class compliant mean?
A class-compliant device (also known as plug-and-play) is one that doesn’t require extra drivers to connect your Windows or Macintosh computer, or to your iPad. These devices use drivers which are built into the host (i.e. the computer or the iPad) operating system.
Which communication protocol is used by USB?
Yes, there is. The USB specification includes the USB protocol which defines the way the bus is used on a bit level. This would be the low-level protocol that underlies the higher level protocols (i.e. mass-storage, HID, etc.).
How fast is USB CDC?
If your code is “fast enough”, the maximum CDC speed is about 1MByte/sec .
What is the base class for a USB device?
This base class is defined for devices that conform to the Content Security Device Class specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined specification are reserved. These class codes can only be used in Interface Descriptors.
What is the hid base class in USB?
This base class is defined for devices that conform to the HID Device Class Specification found on the USB-IF website. That specification defines the usable set of SubClass and Protocol values. Values outside of that defined spec are reserved. These class codes can only be used in Interface Descriptors.
What does base class 10h mean in USB?
Base Class 10h (Audio/Video Devices) The USB Audio/Video (AV) Device Class Definition describes the methods used to communicate with devices or functions embedded in composite devices that are used to manipulate audio, video, voice, and all image- and sound-related functionality.
What are USB class drivers in Windows 10?
Microsoft provides in-box drivers for several of those device classes, called USB device class drivers. If a device that belongs to a supported device class is connected to a system, Windows automatically loads the class driver, and the device functions with no additional driver required.