sequential logic circuit
第五章——触发器是本章的基础！！！
Sequential Logic Overview
Characteristics of sequential logic circuits
- Functionally: the input at any moment not only depends on the input at that moment, but also is related to the original state of the circuit
- Structurally: Sequential logic circuit
基本单元是触发器(that is, the circuit contains a storage circuit)
basic equations
| Equation type | expression | explain |
|---|---|---|
| driving equation | Y = F ( X , Q ) | The storage circuit is the logical relationship between the input of each flip-flop and the initial state and input of the circuit. |
| Equation of state | Q^(n+1) = H ( Z , Q ) | The logical relationship between the secondary state and the initial state of the circuit and its input |
| Output equation | Y = F ( X , Q ) | Logical relationship between output, circuit initial state and input |
- The output equation and driving equation are ordinary combinational logic function expressions (
不涉及初态与次态之间的问题)
Classification of sequential logic circuits
self start
Analysis methods of synchronous sequential logic circuits (*test points)
Analysis steps
flip-flop characteristic equation
State transition table and state transition diagram
Example question analysis
- Synchronous sequential logic circuit (CLK unified)
Commonly used sequential logic circuit modules
- Things to note in the function table of the sequential logic circuit module:
- The meaning of each input signal
- Whether the input signal is synchronized (that is, whether it needs to cooperate with the clock)
Registers and shift registers
counter
binary counter
- Synchronous binary counter
- Asynchronous binary counter
decimal counter
- Synchronized decimal counter
- Asynchronous decimal counter
Arbitrary base counter (*test point)
已有N进制计数器，需要得到M进制计数器
-
M<N
-
M>N
- 2-chip synchronous decimal counter 74160—hundreds counter
- 2-chip synchronous decimal counter 74160 - 29-decimal counter