HCS12 datasheet(337/452 Pages) FREESCALE

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S12CPUV2 Reference Manual, Rev. 4.0

Freescale Semiconductor

337

9.1 Introduction

The instruction set of the central processor unit (CPU12) is the first

instruction set to specifically address the needs of fuzzy logic. This section

describes the use of fuzzy logic in control systems, discusses the CPU12

fuzzy logic instructions, and provides examples of fuzzy logic programs.

The CPU12 includes four instructions that perform specific fuzzy logic tasks.

In addition, several other instructions are especially useful in fuzzy logic

programs. The overall C-friendliness of the instruction set also aids

development of efficient fuzzy logic programs.

This section explains the basic fuzzy logic algorithm for which the four fuzzy

logic instructions are intended. Each of the fuzzy logic instructions are then

explained in detail. Finally, other custom fuzzy logic algorithms are

discussed, with emphasis on use of other CPU12 instructions.

The four fuzzy logic instructions are:

• MEM (determine grade of membership), which evaluates trapezoidal

membership functions

• REV (fuzzy logic rule evaluation) and REVW (fuzzy logic rule

evaluation weighted), which perform unweighted or weighted

MIN-MAX rule evaluation

• WAV (weighted average), which performs weighted average

defuzzification on singleton output membership functions.

Reference Manual — S12CPUV2

Section 9. Fuzzy Logic Support

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