| 摘要 |
A multiplexer is configured on a programmable logic device using a plurality of four-input look-up tables chained together. The required number of look-up tables is about one-half the number of inputs of the multiplexer. For an even number of inputs, the number of look-up tables preferably is exactly one-half the number of inputs, while for an odd number of inputs, the number of look-up tables preferably is one-half the number of inputs, plus one-half. The number of control inputs preferably is one more than the number of look-up tables. Preferably, for any one input being a given logic state, and further selected by the one extra input (beyond the number of look-up tables), any particular output may be asserted.
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