## Control Systems and Computers, N6, 2017, Article 4

DOI: https://doi.org/10.15407/usim.2017.06.035

*Upr. sist. maš., 2017, Issue 6 (272), pp. 35-40.*

UDC 004.2

*Roman M. Babakov – PhD in Techn.Sciences, Associate Professor, Vasyl’ Stus Donetsk National University, 600-richa str., 21, Vinnitsya, 21021, Ukraine, r.babakov@donnu.edu.ua*

*Alexander A. Barkalov – Doctor in Techn. Sciences, Professor, University of Zielona Gora, Podgorna str., 50, Zielona Gora, 65246, Poland, a.barkalov@imei.uz.zgora.pl*

### Microprogram Finite State Machine Modification with the Datapath of Transitions and Replacement of the Input Variables

**Introduction.** The object of research is the microprogram finite state machine with datapath of transitions. In digital devices, microprogram finite state machine performs the functions of control unit and coordinates the work of other units of the system. One of the topical scientific and practical problems is the reduction of hardware expenses in the logical circuit of the microprogram final-state machine. One way to solve this problem is to develop new microprogram final-state machine structures and methods for their synthesis. One of such structures is a microprogram final-state machine with datapath of transitions. In this structure, the transition formation circuit is implemented in the form of an datapath consisting of the separate operational blocks. Each operational block implements its own law of converting the state codes and input signals, realizing a disjoint subset of microprogram transitions.

Herewith, the hardware expenses in the operational block do not depend or depend insignificantly on the number of microprogram transitions it implements. This allows under certain conditions to achieve reducing of hardware expenses in comparison with the implementation of transition function of the finite state machine by the canonical method using the system of Boolean equations.

The approach, consisting in the representation of the circuit for forming the microprogram final-state machine transitions in the form of an datapath, is called the operational realization of the transition function of the finite state machine.

**Purpose**. The purpose of this article is to research a new way for hardware expenses optimization in logical circuit of finite state machine with datapath of transitions.

**Methods**. It is proposed to use in one structure of finite state machine simultaneously two known methods for hardware expenses optimization. The method of comparing the codes of transition operations to the FSM states makes it possible to reduce the complexity of the circuit of the operation codes formation by reducing the number of input signals. The method of replacement of input variables makes it possible to reduce the complexity of the datapath of transitions by reducing the number of functional blocks.

**Results**. A new modification of the microprogram finite state machine structure with datapath of transitions and replacement of input variables is proposed. The peculiarity of this structure is the lower hardware expenses in the logical circuit of finite state machine in comparison with the prototype structures. The general condition of the effectiveness of this structure by the criterion of hardware expenses is determined.

**Conclusion**. Reduction of hardware expenses in the logical circuit of a microprogram finite state machine with datapath of transitions is possible due to the joint use of the several known methods of optimization of hardware expenses. For practical application of the researched structure, it is necessary to develop a synthesis method, which is a combination of synthesis methods of prototype structures. To determine the appropriateness of using the proposed structure, it is required to determine the area of its effective using, which is expressed as a set of values and ranges of the parameters of the finite state machine.

**Keywords**: microprogram finite state machine, datapath of transitions, replacement of input variables, hardware expenses.

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**Received** 02.11.2017