Michael Barr's

Embedded Systems Glossary

Buy the book, which defines over 2,800 commonly used terms.

Last Update: 18 June 2003

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EEPROM

> (double-ee prom) abbr. A type of ROM that can be erased electronically and reprogrammed in-circuit (or with a device programmer). Short for Electrically Erasable Programmable Read Only Memory. From the programmer's perspective, EEPROM is very similar to flash memory. The biggest difference is that the bytes (words) of an EEPROM can be erased individually. [more]

electromagnetic spectrum

> n. The entire range of possible frequencies, from DC to gamma rays and beyond. The spectrum is measured in terms of wavelength or frequency, where wavelength in meters = 3 × 10**8/frequency in hertz. AM radio is at the low end of the spectrum, from 500 kHz to 1.6 MHz; FM radio is around 100 MHz, cell phones at 800 MHz, radar from 2 to 14 GHz, and visible light around 10**6 GHz.

> The electromagnetic spectrum.

embedded C++

> n. A subset of the C++ programming language that is optimized for embedded systems use and supported by some compiler vendors. Abbreviated EC++.

embedded system

> n. A combination of computer hardware and software, and perhaps additional mechanical or other parts, designed to perform a dedicated function. In some cases, embedded systems are part of a larger system or product, as in the case of an antilock braking system in a car. Contrast with general-purpose computer.

> EXAMPLE: Microwave ovens, cell phones, calculators, digital watches, VCRs, cruise missiles, GPS receivers, heart monitors, laser printers, radar guns, engine controllers, digital cameras, traffic lights, remote controls, bread machines, fax machines, pagers, cash registers, treadmills, gas pumps, credit/debit card readers, thermostats, pacemakers, blood gas monitors, grain analyzers, and a gazillion others.

emulator

> 1. See in-circuit emulator.

> 2. n. Any debugging tool that pretends to be a system resource and adds additional functionality or remote visibility. See also ROM emulator.

endianness

> n. The attribute of a hardware or software architecture that indicates how multibyte values are represented and stored. The two possibilities are called big-endian and little-endian. [more]

> HISTORY: The origin of the odd terms big-endian and little-endian can be traced to the 1726 book Gulliver's Travels, by Jonathan Swift. In one part of the story, resistance to an imperial edict to break soft-boiled eggs on the little end escalates to civil war. (The plot is a satire of England's King Henry VIII's break with the Catholic Church.) A few hundred years later, in 1981, Danny Cohen applied the terms and the satire to our current situation in IEEE Computer (vol. 14, no. 10).

EPROM

> (ee-prom) abbr. A type of ROM that can be erased by exposing it to ultraviolet light. Once erased, an EPROM can be reprogrammed with a device programmer. Short for Erasable Programmable Read Only Memory. A window in the device allows ultraviolet radiation to enter the device and reset the ROM circuitry to its initial state. [more]

executable

> n. A file containing object code that is ready for execution on the target. All that remains is to place the object code into a ROM or download it via a debugging tool.

Though originally based on the glossary in the book Programming Embedded Systems in C and C++, this online version has grown considerably and is a living reference. In its present form it represents a subset of the much larger print Embedded Systems Dictionary. If you wish to cite it in your work, you may find the following MLA-style information helpful:

> Barr, Michael. "Embedded Systems Glossary." Online at http://www.netrino.com/Publications/Glossary/. June 2003.