SER 232 Project: Calculator Input Logic

Learning Objectives:

Convert between the three different representations of combinational logic

"In this project, I will be implementing combinational logic circuits in Logisim to handle button input and (eventually) handle output selection from one of four arithmetic circuits . The two combinational digital circuits we are using are a multiplexor and a priority encoder. Then I will use both subcircuits to make a single verification circuit. The following are specifications for each subcircuit.

Multiplexor:

For your calculator, I will 4x1 multiplexor (mux) with four 4-bit inputs and a 4-bit output. The simplest way is by first implementing a 4x1 mux with 1-bit inputs and a 1-bit output in a subcircuit. A 2-bit mux subcircuit can then be created using a pair of 1-bit muxes where both 1-bit muxes share selectors, but splitters are used to separate each 2-bit input into a 1-bit input for each 1-bit mux. The output of each 1-bit mux must also be recombined with a splitter to form the 2-bit output. An equivalent method can be used with a pair of 2-bit mux to form the final 4-bit mux. "