Difference between revisions of "PAL (Chip)"

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A Programmable Array Logic (PAL) is a programmable logic device semiconductors used to implement
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A [https://en.wikipedia.org/wiki/Programmable_Array_Logic Programmable Array Logic (PAL)] is a programmable logic device used to implement any logic function in only one digital circuit. This is useful in applications where you need to reuse the same component for various tasks, and don't want to constantly replace your components. PALs are programmed via a Karnaugh map. They may seem complicated at first, but it's very intuitive once you understand the underlying mechanics.
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any logic function in only one digital circuit. The function is stateless, which means that no
 
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intermediate state is saved.
 
  
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PAL devices consisted of a small PROM (programmable read-only memory) core and additional output
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First the PAL takes the Red Blue and Green inputs and uses it to point at a certain square in the map. Whatever the value inside that square is, will be the output of the PAL. The first square is pointed to if no buttons are pressed at all. Any square in the path of a colored line will be given that color, which then determines which inputs it requires to be pointed at.
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logic used to implement particular desired logic functions with few components.
 
  
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You can use PALs in order to implement any logic function you might need. The PAL chip offers an
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[[File:PAL Color Map.png|thumb]]
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UI where it's logic function can be programmed very simple. The programming is made using a
 
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Karnaugh map. Basically you can specify for each possible state of the three inputs (2 ^ 3 = 8)
 
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the resulting output value. All 3 inputs are represented by bars and for all cells in the map
 
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that are covered by that bar, the corresponding input is considered as 1 (high).
 
  
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Play a little with the 3 buttons and the PAL configuration to see how it works.
 
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Here some examples of standard gates implemented by a PAL:
 
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- AND Gate
 
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{| class="wikitable"
 
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|-
 
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| 0 || 0 || 0 || 0
 
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|-
 
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| 0 || 0 || 1 || 0
 
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|}
 
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- OR Gate
 
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{| class="wikitable"
 
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|-
 
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| 0 || 1 || 1 || 1
 
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|-
 
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| 1 || 1 || 1 || 1
 
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|}
 
 
[[Category:Digital chips]]
 
[[Category:Digital chips]]

Latest revision as of 15:44, 31 August 2018

A Programmable Array Logic (PAL) is a programmable logic device used to implement any logic function in only one digital circuit. This is useful in applications where you need to reuse the same component for various tasks, and don't want to constantly replace your components. PALs are programmed via a Karnaugh map. They may seem complicated at first, but it's very intuitive once you understand the underlying mechanics.

First the PAL takes the Red Blue and Green inputs and uses it to point at a certain square in the map. Whatever the value inside that square is, will be the output of the PAL. The first square is pointed to if no buttons are pressed at all. Any square in the path of a colored line will be given that color, which then determines which inputs it requires to be pointed at.

PAL Color Map.png
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