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درس مدارهای منطقی دانشگاه قم http://lc-qom.blogfa.com / Programmable Logic (PAL, PLA) تهیه شده توسط حسین امیرخانی مبتنی بر اسلایدهای درس مدارهای منطقی دانشگاه امیرکبیر http://ceit.aut.ac.ir/~szamani/index_files/logic.htm. Symbols for OR gate. PLA (Programmable Logic Array). PLA. - PowerPoint PPT Presentation
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درس مدارهای منطقی دانشگاه قمhttp://lc-qom.blogfa.com/
Programmable Logic(PAL, PLA)
تهیه شده توسط حسین امیرخانیمبتنی بر اسالیدهای درس مدارهای منطقی دانشگاه امیرکبیر
http://ceit.aut.ac.ir/~szamani/index_files/logic.htm
Symbols for OR gate
2
3
PLA (Programmable Logic Array)
4
PLA
A 3×2 PLA with 4 product terms
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PLA Pre-fabricated building block of many
AND/OR gates (or NOR, NAND)
General purpose logic building blocks
“Personalized” or “customized” by making/ breaking connections among the gates
This process is called “programming”
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PLA
Sums of Products
Inputs
Dense array of AND gates Product
terms
Dense array of OR gates
Outputs
7
Design for PLA: Example Implement the following functions using PLA
Personality Matrix
1 = asserted in term0 = negated in term- = does not participate
Input Side:
1 = term connected to output0 = no connection to output
Output Side:
Outputs Inputs Product t erm A
1 - 1 - 1
B 1 0 - 0 -
C - 1 0 0 -
F 0 0 0 0 1 1
F 1 1 0 1 0 0
F 2 1 0 0 1 0
F 3 0 1 0 0 1
A B B C A C B C A
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A B C
F0 F1 F2 F3
AB
B’C
AC’
B’C’
A
Personality Matrix
Outputs Inputs Product t erm A
1 - 1 - 1
B 1 0 - 0 -
C - 1 0 0 -
F 0 0 0 0 1 1
F 1 1 0 1 0 0
F 2 1 0 0 1 0
F 3 0 1 0 0 1
A B B C A C B C A
Design for PLA: Example
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Constants
Sometimes a PLA output must be programmed to be a constant 1 or a constant 0.
Manufacturer MAY pull up the AND inputs:− P1 is always 1 is pulled
UP or HIGH.− This constant 1 term
drives the O1 output. Manufacturer MAY pull down
the OR inputs:− O2 is 0.
Another method of obtaining a constant-0 output is shown for O3.
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Inputs
Dense array of AND gates Product
terms
Dense array of OR gates
Outputs
PAL (Programmable Array Logic)
Sums of Products but with a fixed OR array
11
PALinputs
1st output section
2nd output section
3rd output section
4th output section
Only functions withat most four products can be implemented
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13
PAL
W = ABC + CDX = ABC + ACD + ACD + BCD Y = ACD + ACD + ABD
x
x
x
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Final Remark
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A Programmable Logic achieves higher flexibility at the cost of lower speed!
ارشد آزمون تمرینهای
سؤال سال
13 1380
64 1386
68 1388
16
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