Priority encoder: Difference between revisions

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Revision as of 07:51, 9 January 2013

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A '''priority encoder''' is a [[Electronic circuit|circuit]] or [[algorithm]] that compresses multiple [[Binary code|binary]] inputs into a smaller number of outputs. The output of a priority encoder is the binary representation of the ordinal number starting from zero of the most significant input bit. They are often used to control [[interrupt request]]s by acting on the highest priority request.

If two or more inputs are given at the same time, the input having the highest priority will take [[:wikt:precedence|precedence]] .<ref>M. Morris Mano, Michael D. Ciletti, "Digital Design", 4th Edition, Prentice Hall, 2006, ISBN 978-0-13-198924-5.</ref>. An example of a single bit 4 to 2 [[encoder]] is shown, where highest-priority inputs are to the left and "x" indicates an irrelevant value - i.e. any input value there yields the same output since it is superseded by higher-priority input. The output V indicates if the input is valid.

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