Intel PXA27 Series Design Manual page 291

Glossary
Turn-around Time. The time a device needs to wait to begin transmitting a packet after a packet has been received
to prevent collisions on the USB. This time is based on the length and propagation delay characteristics of the cable
and the location of the transmitting device in relation to other devices on the USB.
UART. Universal Asynchronous Receiver/Transmitter serial port
UICC. Universal Integrated Circuit Card, formerly SIM card. A small electronic device about the size of a credit
card that contains an embedded 8-bit microprocessor. The card stores a mathematical algorithm that encrypts voice
and data transmissions. The card also identifies the caller to the mobile network as being a legitimate caller.
UDC. Universal Serial Bus Device Controller. The UDC, which consists of peripheral bus interface, endpoint
memory, endpoint control, and USB interface, provides interface options to a host of peripheral devices at full
speed.
UHC. Universal Serial Bus Host Controller. The UHC in conjunction with the UHC driver serially transfers data
between a shared-memory data structure and the USB controller.
Universal Serial Bus Driver (USBD). The host resident software entity responsible for providing common
services to clients that are manipulating one or more functions on one or more Host controllers.
Universal Serial Bus Resources. Resources provided by the USB, such as bandwidth and power. See also Device
Resources and Host Resources.
Upstream. The direction of data flow towards the host. An upstream port is the port on a device electrically closest
to the host that generates upstream data traffic from the hub. Upstream ports receive downstream data traffic.
USBD. See Universal Serial Bus Driver.
USB-IF. USB Implementers Forum, Inc. is a nonprofit corporation formed to facilitate the development of USB
compliant products and promote the technology.
USB OTG. The USB On-The-Go provides 'dual-role peripheral' capability: it can act as either host or peripheral
depending on how users connect the cable to its unique mini-AB receptacle. When the dual-role device is
connected to the mini-A plug, it turns into a host. When the mini-B plug is connected instead, the device becomes a
peripheral.
Universal Subscriber Identity Module (USIM). The USIM controller is an interface for a GSM mobile handset
that supports communication with SmartCards.
VBI. Vertical Blanking Interval. Also known as the "backporch".
Virtual Device. A device that is represented by a software interface layer. An example of a virtual device is a hard
disk with its associated device driver and client software that makes it able to reproduce an audio.WAV file.
VLIO. Variable Latency Input/Output Interface
YUV. A method of characterizing video signals typically used in digital cameras and PAL television specifying
luminance and chrominance.
WAP. Wireless Application Protocol. WAP is a set of protocols that lets users of mobile phones and other digital
wireless devices access Internet content, check voice mail and e-mail, receive text of faxes and conduct
transactions. WAP works with multiple standards, including CDMA and GSM. Not all mobile devices support
WAP.
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Intel PXA27x Processor Family Design Guide Glossary-15