Fundamentals of Digital Circuits 07

74LS circuit bai is a collection of logic gate circuits, du such as AND gate, NOT gate, NOR gate, OR gate dao. There are mainly two-input three-input gate circuits, such as OR gates, AND gates, NOT gates, NOR gates and so on.

VHDL：

1. The rules are stricter, not loose but not easy to make mistakes;
2. The code for initializing RAM is simpler;
3. Support package;
4. Custom type
5. Enumerated type
6. There is no confusion between reg and wire.

Verilog:

1. The syntax is like C;
2. The code implementation is usually shorter, smaller and more compact;
3. Can be commented in blocks;
4. There is no redundant original instantiation.

The demultiplexer sends the input signal to the combinational logic circuit of the designated output terminal according to the different states of the input address code. This kind of circuit is also called data distributor or demultiplexer.

A circuit that can transmit 1 input data to any one of the m output terminals as needed is called a data distributor, also known as a demultiplexer, and its logic function is just the opposite of the data selector.
Circuit structure: an array composed of AND gates.
Data distribution is to send data from a data source to multiple different channels as needed. The logic circuit that realizes the data distribution function is called a data distributor. Its function is equivalent to a single-pole multi-throw switch with multiple outputs. Its schematic diagram is shown in the figure above. [1] The
data distributor can be implemented with a unique address decoder.
For example, a 3-line-8-line decoder can distribute a data signal to 8 different channels. The logic diagram of using 74138 as the data distributor is as follows:
Connect G2B to low level, G1 as the enable terminal, C, B and A as the selected channel address input, and G2A as the data input. For example, when G1=1 and CBA=010, the function table of 74138 can be obtained:

 

 

When two or more circuits form a network, if the current or voltage in one of the circuits changes, it can affect other circuits to have similar changes. This kind of network is called a coupled circuit. The function of coupling is to transfer (or convert) the energy of a certain circuit to other circuits.