How to build an area-efficient circuit that counts the number of set bits in 15-bit input using 4-input LUTs (look-up tables). The output is obviously 4-bit (counts 0-15). Some claim that it’s possible to do using 9 LUTs.
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How to build an area-efficient circuit that counts the number of set bits in 15-bit input using 4-input LUTs (look-up tables). The output is obviously 4-bit (counts 0-15). Some claim that it’s possible to do using 9 LUTs.
I can do it in 10. It’s a first counter stage (4 tables), then a 2 stage adder with carry (3 and 3 tables).
I suspect there is a way to do better because I didn’t use each LUT completely, but sometimes a simple design is worth the extra cost. I tried other approaches and still needed 10.
Good luck on your homework. (: