Implementation of a configurable fault tolerant processor (CFTP)

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Authors
Johnson, Steven A.
Subjects
Advisors
Loomis, Herschel H.
Date of Issue
2003-03
Date
Publisher
Monterey, California. Naval Postgraduate School
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Abstract
The space environment has unique hazards that force electronic systems designers to use different techniques to build their systems. Radiation can cause Single Event Upsets (SEUs) which can cause state changes in satellite systems. Mitigation techniques have been developed to either prevent or recover from these upsets when they occur. At the same time, modifying on-orbit systems is difficult in a hardwired electronic system. Finding an alternative to either working around a mistake or having to keep the same generation of technology for years is important to the space community. Newer programmable logic devices such as Field Programmable Gate Arrays (FPGAs) allow for emulation of complex logic circuits, such as microprocessors. FPGAs can be repro-grammed as necessary, to account for errors in design, or upgrades in software logic circuits. In an effort to provide one solution for both of these issues, this research was undertaken. The Configurable Fault Tolerant Processor (CFTP) emulates three identical processors, using Triple Modular Redundancy (TMR) to mitigate SEUs on a radiation tolerant FPGA. With the reconfigurable capabilities of FPGA technology, as newer processors can be emulated, these new configurations can be uploaded to the satellite as software code, thereby actually upgrading the processor in flight. This research used a 16-bit Reduced Instruction Set Computer (RISC) processor as its cores. This thesis describes how the Harvard architecture of the processor is interfaced with the Von Neumann architecture of the memory. It also develops the process by which errors are detected and corrected, as well as recorded. The end result is a design simulation ready for implementation on an FPGA.
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Thesis
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Department
Electrical Engineering
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Format
xviii, 119 p. : ill. (some col.) ;
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Approved for public release; distribution is unlimited.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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