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How to take pair at K-MAP
In this chapter, we discuss what is the procedure to take proper pairs at K-MAP to minimize Boolean expression.
Example 1:
Here we define two variable Boolean functions in SOP and POS form:
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Preference order of taking pairs at K-MAP
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We always try to take maximum pairs if possible to minimize the Boolean function.
We always take don’t care term if we try to make pair or longer pair, otherwise, we ignore it.
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Note: In SOP if all 1 is covered, then we do not take extra pairs which are not necessary, and the same for POS, if all 0 is covered then we stop taking unnecessary pairs.
Unnecessary pair gives a redundant result that is not minimized.
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Example 2:
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If we want to cover 1 or pair with 1 then we only take one don’t care term.
Because extra pair with don’t care term makes redundant value.
4-grade pair is not possible. 2-grade pair is possible if we take only one don’t care.
Answer:
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We do not take unnecessary don’t care.
Our aim is to cover all 1’s in SOP
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We are not using this don’t care because it makes redundant pair.
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