Important Digital Logic and Design Short Questions
Chapter: 19
Question 1:
What is a Programmable Array of AND Gates and OR Gates?
Answer:
These are grids of conductors where specific connections can be programmed to create specific logic functions by blowing fuses or shorting conductors.
Chapter: 19
Question 2:
What is the main limitation of a PROM?
Answer:
PROMs have a fixed AND array and are primarily used for storage with limited applications as logic devices. They are not reprogrammable.
Chapter: 19
Question 3:
What is a Programmable Logic Array (PLA)?
Answer:
A PLA is a device with programmable AND and OR arrays that allows users to create custom logic circuits, overcoming the limitations of PROMs.
Chapter: 19
Question 4:
How does a PAL differ from a PLA?
Answer:
A PAL has a programmable AND array and a fixed OR array, making it simpler and faster than a PLA, which has both arrays programmable.
Chapter: 19
Question 5:
What is the main advantage of a Generic Array Logic (GAL) device?
Answer:
GAL devices have a reprogrammable AND array, allowing them to be programmed multiple times, unlike PALs which can only be programmed once.
Chapter: 19
Question 6:
What are the three types of outputs in a PAL?
Answer:
The three types are Combinational Output, Combinational Input/Output, and Programmable Polarity Output. Each is used for different logic functions.
Chapter: 19
Question 7:
How is a PAL identified?
Answer:
PALs are identified by a unique number that includes the prefix 'PAL', followed by the number of inputs, output type (L, H, P), and the number of outputs.
Chapter: 19
Question 8:
What is a 4x3 PLA device?
Answer:
A 4x3 PLA device has 4 inputs, 3 outputs, and a programmable array that can implement a sum-of-product logic expression using up to 6 product terms.
Chapter: 20
Question 9:
What does PLA stand for?
Answer:
PLA stands for Programmable Logic Array.
Chapter: 20
Question 10:
What can a PLA be programmed to output?
Answer:
A PLA can be programmed to output constant 0s or 1s.