Combinatorial logic circuits are digital circuits that produce output signals based on the current input signals, without any memory or feedback. These circuits are composed of various combinatorial blocks such as multiplexers, decoders, and encoders.
Multiplexers (MUX) are combinatorial blocks that allow for the selection of one of several input signals to be passed through to the output based on the value of one or more selection lines. A multiplexer is also known as a data selector. A MUX has multiple input lines and one output line. The selection of which input line is passed through to the output is determined by the value of the selection lines, which are also known as control lines.
FOR EXAMPLE, a 2-to-1 MUX has two input lines, one output line, and one selection line. If the selection line is at a logic 0, the first input line is passed through to the output. If the selection line is at a logic 1, the second input line is passed through to the output.
Decoders are combinatorial blocks that convert a binary code into a set of outputs. A decoder has 2^n input lines and n output lines, where n is the number of input lines. The input lines carry the binary code, and the output lines are activated based on the binary code.
FOR EXAMPLE, a 2-to-4 decoder has two input lines and four output lines. If the input lines are at 00, the first output line is activated. If the input lines are at 01, the second output line is activated, and so on.
Encoders are combinatorial blocks that convert a set of inputs into a binary code. An encoder has n input lines and log2(n) output lines, where n is the number of input lines. The input lines represent a set of inputs, and the output lines carry the binary code corresponding to the activated input line.
FOR EXAMPLE, a 4-to-2 encoder has four input lines and two output lines. If the first input line is activated, the output lines will be at 00. If the second input line is activated, the output lines will be at 01, and so on.
Multiplexers, Decoders, And Encoders are important combinatorial blocks used in digital circuits. They allow for the selection, conversion, and encoding of signals, respectively, and play a crucial role in the functioning of various digital devices and systems.