| 摘要 |
Efficient implementations of wide logic functions (e.g., priority encoders, AND gates, OR gates) in programmable ICs include carry chain multiplexers driven by dual-output programmable function generators. A function generator having two output signals is programmed to generate first and second function output signals. The first and second functions can optionally share some or all of the input signals. The first function output signal drives the select terminal of a carry multiplexer, which selects between a carry in input signal and the second function output signal to provide the carry out output signal. The wide function result is provided by the final carry multiplexer in a chain of such carry multiplexers. In an exemplary wide AND gate, the first function is an AND function, and the second function is ground. In an exemplary wide OR gate, the first function is a NOR function, and the second function is power high VDD.
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