10.4: Conclusion

State machines are simple calculation machines which use a state and next state logic to implement simple algorithms such as counters. State machines are also a part of any larger calculation machine such as a computer.

State machines can be implemented in hardware using some sort of memory to store a state, and next state logic which allows the machine to advance from one state to another. The memory used to store the state in this chapter was D flip-flops.

The next state logic was implemented in two ways in this chapter. The first was by a circuit which implemented combinational logic to calculate the next state of the circuit. The second way next state logic was implemented was using a ROM chip where the current state was used as an address to the memory in the ROM chip which contained a value for the next state. Using a ROM chip in this way was called micro-programming.

The chapter then continued by showing how a ROM chip could be simulated using a MUX with hard wired values as inputs, and the select lines as addresses to the values to choose.

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