1. Field of the Invention
The present invention relates to a semiconductor LSI design device and designing method used for control devices in which high safety is required.
2. Description of the Related Art
In nuclear power plants, a safety protection system is installed to perform control such as emergency nuclear reactor shutdown, shutoff of various valves for preventing leakage of radioactive materials, and the like on the basis of an input from a radiation measurement device or various other sensors.
In the past, a microcomputer has been used as a control device, but when the same software is used for a redundant system by device multiplexing, there is a possibility of a device multiplexing function being damaged due to a defect of software. Further, when a memory cell of a storage device is irradiated with radiation such as cosmic rays, a phenomenon called a soft error in which charges are lost and data is rewritten is likely to occur, leading to an accidental abnormal operation. In addition, there is a growing demand for tamper resistance such as software rewrite prevention.
For this reason, in a control device of a nuclear power plant or the like in which high safety is required, a processor-less hardwired system is required for the purpose of improving security.
A background art is disclosed in Japanese Patent No. 4371856 (patent document 1).
“An safety instrumentation system of a nuclear reactor constructed using a digital logic mounted on hardware selected from an ASIC and an FPGA, including a digital logic portion which is configured using at least one of a functional unit which is verified in advance at a stage before output logical patterns with respect to all input logical patterns are mounted and a functional module constituted by combining the verified functional units, wherein the functional module is configured only with functional units having the same logical configuration as the verified functional units” is disclosed in patent document 1.