Document Number: 001-76294 Rev. *F Page 18 of 21
Acronyms
The following table lists the acronyms used in this document.
Reference Documents
USB 2.0 Specification
Document Conventions
Units of Measure
Glossary
Acronym Description
DC Direct Current
GPIO General Purpose Input/Output
I/O Input/Output
LED Light Emitting Diode
PC Personal Computer
SSOP Shrink Small Outline Package
UART Universal Asynchronous Receiver / Transmitter
USB Universal Serial Bus
Symbol Unit of Measure
°C degree Celsius
k kilohm
A microampere
mA milliampere
ohm
% percent
s second
V volt
W watt
Asynchronous A signal whose data is acknowledged or acted upon immediately, irrespective of any clock signal.
Buffer 1. A storage area for data that is used to compensate for a speed difference, when transferring data from one
device to another. Usually refers to an area reserved for I/O operations, into which data is read, or from which
data is written.
2. A portion of memory set aside to store data, often before it is sent to an external device or as it is received
from an external device.
3. An amplifier used to lower the output impedance of a system.
Flash Flash is a type of non-volatile memory used to store small amounts of data that must be saved when power is
removed.
Reset No Connect (NC)
V
DD
A name for a power net meaning “voltage drain” The most positive power supply signal. Usually 5 V or 3.3 V.
V
SS
A name for a power net meaning “voltage source” The most negative power supply signal.
Virtual COM Port A USB virtual COM port is a software interface that enables applications to access a USB device as if it were a
built-in serial port. Many USB virtual COM-port devices function as bridges that convert between USB and RS-232
or other asynchronous serial interfaces.
UART
A UART or universal asynchronous receiver-transmitter translates between parallel bits of data and serial bits.
