electronics Electronics is a scientific and engineering discipline that studies and applies the principles of physics to design, create, and operate devices that manipulate electrons and other Electric charge, electrically charged particles. It is a subfield ...

, glue logic is the custom logic circuitry used to interface a number of off-the-shelf

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

s. This is often achieved using common, inexpensive 7400- or 4000-series components. In more complex cases, a

programmable logic device A programmable logic device (PLD) is an electronic component used to build reconfigurable digital circuits. Unlike digital logic constructed using discrete logic gates with fixed functions, the function of a PLD is undefined at the time of m ...

like a CPLD or

FPGA A field-programmable gate array (FPGA) is a type of configurable integrated circuit that can be repeatedly programmed after manufacturing. FPGAs are a subset of logic devices referred to as programmable logic devices (PLDs). They consist of a ...

might be used. The falling price of programmable logic devices, combined with their reduced size and power consumption compared to discrete components, is making them common even for simple systems. In addition, programmable logic can be used to hide the exact function of a circuit, in order to prevent a product from being cloned or counterfeited. The software equivalent of glue logic is called

glue code In computer programming, glue code is code that allows components to interoperate that otherwise are incompatible. The adapter pattern describes glue code as a software design pattern. Glue code describes language bindings or foreign function ...

Usage

Typical functions of glue logic include: * Simple logic functions. * Address decoding circuitry used with older processors like the

MOS Technology 6502 The MOS Technology 6502 (typically pronounced "sixty-five-oh-two" or "six-five-oh-two") William Mensch and the moderator both pronounce the 6502 microprocessor as ''"sixty-five-oh-two"''. is an 8-bit computing, 8-bit microprocessor that was desi ...

Zilog Z80 The Zilog Z80 is an 8-bit computing, 8-bit microprocessor designed by Zilog that played an important role in the evolution of early personal computing. Launched in 1976, it was designed to be Backward compatibility, software-compatible with the ...

to divide up the processor's address space into RAM, ROM and I/O. Newer versions of these processors, such as the WDC 65816 or the

Zilog eZ80 The Zilog eZ80 is an 8-bit microprocessor designed by Zilog as an updated version of the company's first product, the highly-successful Zilog Z80. The eZ80 is binary compatible with the Z80, but it operates almost three times faster at the same ...

, may add features that enable glueless interfacing to external devices. *Buffers to protect outputs from overload, or protect sensitive inputs from

electrostatic discharge Electrostatic discharge (ESD) is a sudden and momentary flow of electric current between two differently-charged objects when brought close together or when the dielectric between them breaks down, often creating a visible electric spark, spark as ...

damage. *Voltage level conversion, ''e.g.'', when interfacing one logic family (

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss ", , ) is a type of MOSFET, metal–oxide–semiconductor field-effect transistor (MOSFET) semiconductor device fabrication, fabrication process that uses complementary an ...

) to another ( TTL).

References

Electrical circuits {{electronics-stub

Usage

See also

References