Practice question · Numerical answer
A lookup table stores the output bit for every possible combination of its inputs. How many configuration bits does one 6-input LUT hold?
Hints
- Count the input combinations first: each of the 6 inputs is 0 or 1.
- One stored output bit is needed per combination.
Show the answer
64
Why
Six inputs give 2^6 = 64 combinations, and the LUT stores one output bit for each, so 64 bits. That is what lets a single LUT become any Boolean function of 6 inputs, the function is not built from gates, it is looked up. Answering 6 or 12 mistakes the number of inputs for the number of things they can spell.
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