electronics The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification ...

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

integrated circuit An integrated circuit or monolithic integrated circuit (also referred to as an IC, a chip, or a microchip) is a set of electronic circuits on one small flat piece (or "chip") of semiconductor material, usually silicon. Large numbers of tiny ...

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, a PLD has an undefined function at the time of manu ...

like a CPLD or

FPGA A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware d ...

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 Cloning is the process of producing individual organisms with identical or virtually identical DNA, either by natural or artificial means. In nature, some organisms produce clones through asexual reproduction. In the field of biotechnology, ...

or counterfeited. The software equivalent of glue logic is called

glue code Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...

Usage

Typical functions of glue logic may 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 microprocessor that was designed by a small te ...

Zilog Z80 The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were ...

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, 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 electrically charged objects caused by contact, an electrical short or dielectric breakdown. A buildup of static electricity can be caused by tribochar ...

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

CMOS Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSF ...

) to another ( TTL).

References

Electrical circuits {{electronics-stub

Usage

See also

References