Wyniki wyszukiwania - Biblioteka Nauki

1

Improving the LUT count for Mealy FSMs with transformation of output collections

100%

Barkalov A. , Titarenko L. , Mazurkiewicz M.

|

2022

|

tom Vol. 32, no. 3

479--494

EN

A method is proposed which aims at reducing the number of LUTs in the circuits of FPGA-based Mealy finite state machines (FSMs) with transformation of collections of outputs into state codes. The reduction is achieved due to the use of two-component state codes. Such an approach allows reducing the number of state variables compared with FSMs based on extended codes. There are exactly three levels of LUTs in the resulting FSM circuit. Each partial function is represented by a single-LUT circuit. The proposed method is illustrated with an example of synthesis. The experiments were conducted using standard benchmarks. They show that the proposed method produces FSM circuits with significantly smaller LUT counts compared with those produced by other investigated methods (Auto and One-hot of Vivado, JEDI, and transformation of output collection codes into extended state codes). The LUT count is decreased by, on average, from 9.86% to 59.64%. The improvement of the LUT count is accompanied by a slightly improved performance. The maximum operating frequency is increased, on average, from 2.74% to 12.93%. The advantages of the proposed method become more pronounced with increasing values of FSM inputs and state variables.

2

Improving LUT count of FPGA-based sequential blocks

100%

Barkalov A. , Titarenko L. , Mazurkiewicz M. , Krzywicki K.

|

tom Vol. 69, nr 2

art. no. e136728

EN

Very often, a digital system includes sequential blocks which can be represented using a model of the finite state machine (FSM). It is very important to improve such FSM characteristics as the number of used logic elements, operating frequency and consumed energy. The paper proposes a novel technology-dependant design method targeting LUT-based Mealy FSMs. It belongs to the group of structural decomposition methods. The method is based on encoding the product terms of Boolean functions representing the FSM circuit. To diminish the number of LUTs, a partition of the set of internal states is constructed. It leads to three-level logic circuits of Mealy FSMs. Each function from the first level requires only a single LUT to be implemented. The method of constructing the partition with the minimum amount of classes is proposed. There is given an example of FSM synthesis with the proposed method. The experiments with standard benchmarks were conducted. They show that the proposed method can improve such FSM characteristics as the number of used LUTs. This improvement is accompanied by a decrease in performance. A positive side effect of the proposed method is a reduction in power consumption compared with FSMs obtained with other design methods.

3

Reducing the number of LUTs for Mealy FSMs with state transformation

100%

Barkalov A. , Titarenko L. , Mielcarek K.

International Journal of Applied Mathematics and Computer Science

|

2024

|

tom Vol. 34, no. 1

167--178

EN

In many digital systems, various sequential blocks are used. This paper is devoted to the case where the model of a Mealy finite state machine (FSM) represents the behaviour of a sequential block. The chip area occupied by an FSM circuit is one of the most important characteristics used in logic synthesis. In this paper, a method is proposed which aims at reducing LUT counts for FPGA-based Mealy FSMs with transformation of state codes into FSM outputs. This is done using the combined state codes. Such an approach allows excluding a block of transformation of binary state codes into extended state codes. The proposed method leads to LUT-based Mealy FSM circuits having exactly three levels of logic blocks. Under certain conditions, each function for any logic level is represented by a circuit including a single LUT. The proposed approach is illustrated with an example of synthesis. The results of experiments conducted using standard benchmarks show that the proposed method produces LUT-based FSM circuits with significantly smaller LUT counts than is the case for circuits produced by other investigated methods (Auto and One-hot of Vivado, JEDI, and transformation of binary codes into extended state codes). The LUT count is decreased by an average of 17.96 to 91.8%. Moreover, if some conditions are met, the decrease in the LUT count is accompanied with a slight improvement in the operating frequency compared with circuits based on extended state codes. The advantages of the proposed method multiply with increasing the numbers of FSM inputs and states.

4

Improving characteristics of LUT-based Mealy FSMs

100%

Barkalov A. , Titarenko L. , Mielcarek K.

International Journal of Applied Mathematics and Computer Science

|

2020

|

tom Vol. 30, no. 4

745--759

EN

Practically, any digital system includes sequential blocks represented using a model of finite state machine (FSM). It is very important to improve such FSM characteristics as the number of logic elements used, operating frequency and consumed energy. The paper proposes a novel technology-dependent design method targeting a decrease in the number of look-up table (LUT) elements and their levels in logic circuits of FPGA-based Mealy FSMs. It produces FSM circuits having three levels of logic blocks. Also, it produces circuits with regular systems of interconnections between the levels of logic. The method is based on dividing the set of internal states into two subsets. Each subset corresponds to a unique part of an FSM circuit. Only a single LUT is required for implementing each function generated by the first part of the circuit. The second part is represented by a multi-level circuit. The proposed method belongs to the group of two-fold state assignment methods. Each internal state is encoded as an element of the set of states and as an element of some of its subsets. A binary state assignment is used for states corresponding to the first part of the FSM circuit. The one-hot assignment is used for states corresponding to the second part. An example of FSM synthesis with the proposed method is shown. The experiments with standard benchmarks are conducted to analyze the efficiency of the proposed method. The results of experiments show that the proposed approach leads to diminishing the number of LUTs in the circuits of rather complex Mealy FSMs having more than 15 internal states. The positive property of this method is a reduction in energy consumption (without any overhead cost) and an increase in operating frequency compared with other investigated methods.