Page 42 - Engineering Digital Design

1.4 GLOSSARY OF TERMS, EXPRESSIONS, AND ABBREVIATIONS 13

EAIC system: externally asynchronous/internally clocked system.
ECL: emitter-coupled logic.
Edge-triggered flip-flop: a flip-flop that is triggered on either the rising edge or falling
edge of the clock waveform and that exhibits the data-lock-out feature.
EEPROM: electrically erasable PROM.
E-hazard: essential hazard.
El: enable-in.
Electron: the majority carrier in an n-type conducting semiconductor.
Electronic switch: a voltage or current controlled switching device.
Emitter: one of three terminals of a BIT.
Emitter-coupled logic (ECL): a high-speed nonsaturating logic family.
EN: enable.
Enable: an input that is used to enable (or disable) a logic device, or that permits the
device to operate normally.
Encoder: a digital device that converts digital signals into coded form.
Endless cycle: an oscillation that occurs in asynchronous FSMs.
Enhancement mode: a normally OFF NMOS that develops an n-channel drain-to-source
conducting path (i.e., turns ON) with application of a sufficiently large positive gate
voltage.
Entered variable (EV): a variable entered in a K-map.
EO: enable-out.
EPI: essential prime implicant.
EPLD: erasable PLD.
EPROM: erasable programmable read-only memory.
EQPOS: EQV-product-of-sums.
Equivalence: the output of a two-input logic gate that is active if, and only if, its inputs
are logically equivalent (i.e., both active or both inactive).
EQV: equivalence.
EQV function: the function that derives from the definition of equivalence.
EQV gate: a physical device that performs the electrical equivalent of the EQV function.
EQV laws: a set of Boolean identities based on the EQV function.
Erasable programmable read-only memory (EPROM): a ROM that can be program-
med many times.
Error catching: a serious problem in a JK master/slave flip-flop where a 1 or 0 is caught
in the master cell when clock is active and is issued to the slave cell output when clock
goes inactive.
Essential hazard: a disruptive sequential hazard that can occur as a result of an explicitly
located delay in an asynchronous FSM that has at least three states and that is operated
in the fundamental mode.
Essential prime implicant (EPI): a prime implicant that must be used to achieve mini-
mum cover.
EU: execution unit.
EV: entered variable.
EV K-map: a K-map that contains EVs.
EV truth table: a truth table containing EVs.
Even parity: an even number of 1's (or O's) in a binary word depending on how even
parity is defined.