4 to 16 decoder using 2 to 4 decoder verilog code

From the above circuit, the signals from NOT and AND gates can be treated as intermediate signals. These are signals that are not the terminal ports. At any time, only one of these 4 inputs can be ‘1’ in order to get the respective binary code at the output.įigure 5.Now, we can declare the intermediate signals. The 4 to 2 Encoder consists of four inputs Y3, Y2, Y1 & Y0 and two outputs A1 & A0. Therefore, the encoder encodes 2 n input lines with ‘n’ bits. It will produce a binary code equivalent to the input, which is active High. 2) EncoderĪn Encoder is a combinational circuit that performs the reverse operation of Decoder.It has maximum of 2 n input lines and ‘n’ output lines, hence it encodes the information from 2 n inputs into an n-bit code. Hence the output of the decoder is dependent on whether the Enable is high or low.

When Enable is 1, the AND gates get one of the inputs as 1, and now the output depends upon the remaining inputs. If Enable is 0, all AND gates are supplied with one of the inputs as 0 and hence no output is produced. Only a small change in the implementation is required: the Enable input is fed into the AND gates which produce the outputs. Output is only generated when the Enable input has value 1 otherwise, all outputs are 0. This extra input allows the decoders outputs to be turned “ON” or “OFF” as required.

Therefore, whichever output line is “HIGH” identifies the binary code present at the input, in other words it “decodes” the binary input.Some binary decoders have an additional input pin labelled “Enable” that controls the outputs from the device. The binary inputs A and B determine which output line from Q0 to Q3 is “HIGH” at logic level “1” while the remaining outputs are held “LOW” at logic “0” so only one output can be active (HIGH) at any one time. Logic Diagram and Truth table of 2-to-4 Decoder

Each output represents one of the minterms of the 2 input variables, (each output = a minterm).įigure 3. The 2 binary inputs labelled A and B are decoded into one of 4 outputs, hence the description of 2-to-4 binary decoder. The 2-to-4 line binary decoder depicted above consists of an array of four AND gates. The name “Decoder” means to translate or decode coded information from one format into another, so a digital decoder transforms a set of digital input signals into an equivalent decimal code at its outputĪ decoder is a combinational circuit that converts binary information from n input lines to a maximum of m=2^n unique output lines.įigure 2. Encoders convert 2 N lines of input into a code of N bits and Decoders decode the N bits into 2 N lines. This is what encoders and decoders are used for. Introductionīinary code of N digits can be used to store 2 N distinct elements of coded information. Implementation and verification of decoder/de-multiplexer and encoder using logic gates.

4 to 16 decoder using 2 to 4 decoder verilog code