In digital logic, a don't-care term is an input-sequence (a series of bits) to a function that the designer does not care about, usually because that input would never happen, or because differences in that input would not result in any changes to the output. By using these don't-care inputs, designers can potentially minimize their function much more so than if the don't-care inputs were taken to have an output of all 0 or all 1. An example of a would be the binary values 1010 through 1111 (10 through 15) for a function that takes a BCD value, because a BCD value is never made up of the values 1010 to 1111. Don't-care terms are important to consider in minimizing using Karnaugh maps and the Quine–McCluskey algorithm.

See also

• Karnaugh map
• Quine–McCluskey algorithm

References

• An explanation on boolean simplification and don't-care terms