Example:

Decoding: "Translate" the input code into another code output. and the reverse process of the encoder.

2-wire to 4-wire decoder (74HC139)

3-wire to 8-wire decoder (74HC138)

4-line to 16-line decoder (74HC154)

Seven-segment display decoder

Encoding: Compile each signal of a set of encoding inputs into a corresponding output code.

Ordinary encoder: Only one encoding signal is allowed to be input during normal operation, and more than two encoding input signals are not allowed to be input at the same time, otherwise the output will be in an error state.

Priority encoder: When there are more than two encoding input signals at the same time, only the one with the highest priority is encoded.

Select one from a set of input data and send it to the output

half adder

full adder

One bit numerical comparator

Multi-bit numerical comparator

①Select data selector

②Choose a decoder