Page 38 - Engineering Digital Design

1.4 GLOSSARY OF TERMS, EXPRESSIONS, AND ABBREVIATIONS

Carry-out: the carry output from an Adder.
Carry propagate: a function that is used in a CLA adder.
Carry save (CS): a fast addition method for three or more binary numbers where the
carries are saved and added to the final sum.
Cascade: to combine identical devices in series such that any one device drives another;
to bit-slice.
Cell: the intersection of all possible domains of a K-map.
Central processing unit (CPU): a processor that contains the necessary logic hardware
to fetch and execute instructions.
CGP: carry generate/propagate.
CI: carry-in.
Circuit: a combination of elements (e.g., logic devices) that are connected together to
perform a specific operation.
CK: clock.
CL or CLR: clear.
CLA: carry look-ahead.
CLB: configurable logic block. Also, a logic cell (LC).
Clear: an asynchronous input used in flip-flops, registers, counters and other sequential
devices, that, when activated, forces the internal state of the device to logic 0.
Clock: a regular source of pulses that control the timing operations of a synchronous
sequential machine.
Clock skew: a phenomenon that is generally associated with high frequency clock dis-
tribution problems in synchronous sequential systems.
C-module: an RMOD.
CMOS: complementary configured MOSFET in which both NMOS and PMOS are used.
CNT: mnemonic for count.
CO: carry-out.
Code: a system of binary words used to represent decimal or alphanumeric information.
Code converter: a device designed to convert one binary code to another.
Collapsed truth table: a truth table containing irrelevant inputs.
Collector: one of three regions in a BIT.
Combinational hazard: a hazard that is produced within a combinational logic circuit.
Combinational logic: a configuration of logic devices in which the outputs occur in
direct, immediate response to the inputs without feedback.
Commutative law: the Boolean law that states that the order in which variables are
represented in a p-term or s-term does not matter.
Comparator: a combinational logic device that compares the values of two binary num-
bers and issues one of three outputs indicative of their relative magnitudes.
Compatibility: a condition where the input to a logic device and the input requirement
of the device are of the same activation level, that is, are in logic agreement.
Compiler: converts high-level language statements into typically a machine-coded or
assembly language form.
Complement: the value obtained by logically inverting the state of a binary digit; the
relationship between numbers that allows numerical subtraction to be performed by an
addition operation.
Complementary metal oxide semiconductor (CMOS): a form of MOS that uses both
p- and n-channel transistors (in pairs) to form logic gates.