What is the Difference Between PLA and ROM?

PLA (Programmable Logic Array) and ROM (Read-Only Memory) are used to implement logic functions, but they have different characteristics and uses. Here are the main differences between PLA and ROM:

1. Configurability: In PLA, both AND and OR arrays are configurable, while in ROM, only the OR gates array is configurable. This means that PLA can be programmed to implement a wider range of logic functions than ROM.
2. Don't Care Terms: PLA has the capability to take 'don't care terms' (Boolean overlaps) into account, while ROM does not have this capability. This makes PLA more flexible in implementing certain types of logic functions.
3. Combinational vs. Sequential: ROM is a combinational circuit, while PLA can be either combinational or sequential. This means that PLA can be used for a wider range of applications, including state-based logic and finite state machines.
4. Data Storage: ROM is used to store data, while PLA is used for implementing various combinational circuits. This makes ROM suitable for storing programs and lookup tables, while PLA is more focused on implementing logic functions.

In summary, while both PLA and ROM can be used to implement logic functions, PLA is more versatile and can be programmed to implement a wider range of functions, including state-based logic and finite state machines. ROM, on the other hand, is primarily used for data storage and lookup tables.

Comparative Table: PLA vs ROM

Here is a table highlighting the key differences between PLA (Programmable Logic Array) and ROM (Read Only Memory):

In summary, PLA is a digital logic device made up of programmable AND and OR gates that can implement logic functions, while ROM is a memory device that stores data and does not perform logic functions. PLA offers more flexibility and configurability compared to ROM, but it may come with higher manufacturing costs.