Programmable Array Logic (PAL) is a type of semiconductor used to implement logic functions in digital circuits.
PAL is a type of programmable logic device, which is a term for an integrated circuit that can be programmed in a laboratory to perform complex functions.
The device consists of a programmable read-only memory core with an output logic which is used ot implement logic functions with few components.
PAL devices are field-programmable, which means that it can be configured after manufacturer by a users. There were several versions, some allowing it to be reprogrammed only once and some which could be erased for re-use.
What was used before the PAL?
Before the introduction of PALs a designer of digital logic circuits use to use small-scale integration components. However, a PAL is much more efficient and a single one is capable of replacing multiple SSIs.
The project to create the PAL device was headed by John Birkner but the circuit of the PAL was designed by H.T. Chua.