Glue logic

In electronics, glue logic is the custom logic circuitry used to interface a number of off-the-shelf integrated circuits.

This is often achieved using ordinary (cheap) 7400- or 4000-series components. In more complex cases, programmable logic devices like a CPLD or FPGA 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 (see: reverse engineering).