Three-state buffer (Three-state buffer), also known as three-state gate, three-state driver, its three-state output is controlled by the enable output, when the enable output is valid, the device realizes the normal logic state output (logic 0, Logic 1), when the enable input is invalid, the output is in a high-impedance state, which is equivalent to disconnecting from the connected circuit.
The buffer is one of the digital components. It does not perform any operation on the input value, and its output value is the same as the input value, but it plays an important role in the design of the computer.
There are two types of buffers, commonly used buffers (regular buffers) and tri-state buffers. The conventional buffer always outputs the value directly, and is used to output the current to the higher-level circuit system. In addition to the functions of conventional buffers, tri-state buffers also have an optional cartoon input terminal, denoted by E. There are different output values when E=0 and E=1.
The buffer can be divided into input buffer and output buffer. The former's role is to temporarily store the data sent by the peripheral device so that the processor can take it away; the latter's role is to temporarily store the data sent by the processor to the peripheral device. With the NC buffer, you can make the high-speed CPU and slow-working peripherals coordinate and buffer, and synchronize data transmission. Because the buffer is connected to the data bus, it must have a three-state output function.
When E=1, the gate is selected, and its input is directly sent to the output;
If E=0, the buffer is blocked, no matter what value is input, the output is always high impedance, denoted by Z. The high-impedance state allows the current to drop sufficiently low that the output of a similar buffer is not connected to anything.
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