Glue logic

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In electronics, glue logic refers to the custom electronic circuitry needed to achive compatible interfaces between two (or more) differrent off-the-shelf integrated circuits. This is often achieved by employing a few 7400 series compatible components, or, in complex cases, a CPLD or FPGA.

An example of glue logic is the address decoder which with older processors like the 6502 or Z80 had to be added externally to divide up the addressing space of the processor into RAM, ROM and I/O. Newer processors such as the Zilog Z180 instead have an internal address decoder so glueless interfacing to the most common external devices becomes possible.