A state machine is a state machine that consists of a switching logic and a state memory. State machines are used for the processing of simple commands, for example in transponders of RFID tags, where they are used in the address and security logic, or in TCP connections, where they define the exact states for transitions.
The switching network of a State-Machine receives a variable input via its inputs and additionally the switching state of the state memory. The switching state is represented by the previous state variables. The output signal of the state machine is an output variable that depends on the input variable and the state variable. The output variable can take two states, but they depend on the last state variable and the input variable. Thus the sequence of the state sequence with the input variable can be influenced with the clock signal of the state memory.