MICROCOMPUTER AND ITS ACCESS SPEED CONTROL METHOD

摘要

A microcomputer usable for a long period of time even when disposed in a high dose radiation-exposed environment, and its access speed control method are provided. According to the microcomputer and the method, the total dose of radiation that the microcomputer receives is determined on the basis of detection signals from a radiation detecting element. Based on the determined total dose of radiation, and table data preset by tests and stored into a memory unit, a CPU controls an access speed. Moreover, the CPU, and the memory unit and a circuit interface unit that access the CPU are integrated on a single chip (ASIC). These units on the same chip are deteriorated and changed in the same direction, without fail, on exposure to radiation. 19