Programmable Array Logic PPT by Shaurya21csu189.pptx
- 1. Programmable Array Logic By Shaurya Bahl (21CSU189)
- 2. Contents • Definition of Programmable Array Logic (PAL) • Block Diagram of PAL • Circuit Diagram of PAL • Comparison with other Programmable Logic Devices • Example of PAL • Advantages of PAL
- 3. Definition of Programmable Array Logic (PAL) • Programmable Array Logic (PAL) is a commonly Used programmable logic device (PLD). It has programmable AND array and fixed OR array. • It is easier to use but not flexible as compared to Programmable Logic Array (PLA) because only the AND array is programmable. • The Limitation of PAL is number of AND gates. • PAL consists of small Programmable Read Only Memory (PROM) and additional output logic used to implement a particular desired logic function with limited components.
- 4. Block Diagram of Programmable Array Logic
- 6. Comparison with other Programmable Logic Devices • Main Difference between PLA, PAL and ROM is their basic structure. • In PLA, Programmable AND gate is followed by programmable OR gate. • In PAL, programmable AND gate is followed by fixed OR gate. • In ROM, fixed AND gate is followed by programmable OR gate array.
- 7. Example of PAL (1 of 2) • Example 1: Implement the Boolean functions F1= A’BC’D + A’BCD’ + ABC’D and F2= A’BC’ + A’BC + AB’C + ABC’ with PAL device. • Solution: The given Boolean expressions can be simplified to get a reduced equation:
- 8. Example of PAL (2 of 2) • The simplified expression can be realized using PAL. The given function has four inputs and two outputs. • It has five product terms. Each Product term is obtained by placing the fuse link to the corresponding input line.
- 9. Advantages of PAL • Highly Efficient • Low Production cost as compared to PLA • Highly secure • High Reliability • Low power required for working • More flexible to design
- 10. Thank You