USB Cords

• Host: A PC or other computer that enumerates and communicates to devices
• Embedded Host: Embedded products such as set-top boxes, video game consoles and data loggers that have some of the capabilities of a PC host
• Device: Peripherals such as mice, keyboards, flash drives, and printers, that follow the commands of the host or embedded host
• On-the-Go (OTG): The capability of an application to act as either an embedded host or a device; an OTG application historically had a single Micro AB connector to perform the host or device role
• Dual-Role: The capability of an application to act as an embedded host or a device; this type of application has two separate connectors for each role: a Type-A connector for host and Type-B connector for device
• Enumeration: The process by which a USB host learns about a USB device that has just been connected to the bus; before the application is able to start running, the host queries the device to determine what type of device it is, what device driver it needs to load for the device, what power requirements the device has, etc.

There are many types of connectors for USB including: Type-A, Type-B, Mini-A, Mini-AB, Mini-B, Micro-AB, Standard A, Standard B, USB 3.0 Micro-B, and Type-C®. While Micro USB connectors are the most common on cell phones for charging and connectivity, the Type-C connector has been designed to support USB 2.0, USB 3.0, USB 3.1 and USB 3.2 specifications reaching up to 20 Gbps data rates for use in new smaller, thinner and lighter devices.

USB Types Chart

A USB controller handles all the communication via a USB stack running on a microcontroller (MCU), while a PHY provides the physical interface to the cable. Some hubs and MCUs integrate all components required for a USB system into a single IC.

Check out our scalable portfolio of microcontrollers (MCUs) and Digital Signal Controllers (DSCs) with integrated USB or our highly configurable stand-alone USB controllers, hubs, transceivers, switches and bridges.

There is a difference between the terms Hi-Speed USB and USB 2.0. USB 2.0 is the specification, while "Hi-Speed USB" refers to just the 480 Mbps portion of the USB 2.0 specification. A device can still be USB 2.0 compliant and be full speed or low speed.

• USB 2.0 supports 1.5 Mbps (low speed),12 Mbps (full speed) and 480 Mbps (high speed) transfer speeds.
• USB 3.0 adds SuperSpeed USB, which supports speeds up to 5 Gbps.
• USB 3.1 updates USB 3.0 to support speeds up to 10 Gbps
• USB 3.2 allows up two lanes of 10 Gbps operation to realize a 20 Gbps data transfer rate

The host is the root of the USB tiered star network. It controls the bus and initiates communication. The USB protocol mandates a single host in any USB system.

In general, a USB peripheral or device is something that connects to the USB host and uses some USB function such as data transfer or power transfer. Note that a “function” is some action enabled by the USB specification, such as Hi-Speed data transfer. Examples of devices and peripherals are physical items such as keyboards, storage devices, or portable electronics like mobile phones or portable game consoles. A USB hub is both a device and peripheral to the host.