working area einbrenntestschaltung and einbrenntestverfahren

摘要

This invention discloses a microcomputer and a method of its burn-in test in which the burn-in test for detecting the initial defects of the parts necessary to detect the defects of the microcomputer is carried out while keeping the microcomputer mounted on the same burn-in test device. When a burn-in test mode signal is activated by a mode decoder, a mode switching circuit carries out switching so as to activate either one of a ROM dump mode signal or a test ROM execution signal, by means of a mode switching signal from a mode switching terminal. A central processing unit dumps data of the user ROM when the ROM dump mode signal is activated, and executes a program stored in the test ROM when the test ROM execution signal is activated, to gain access to various parts of the microcomputer. A reset signal is used as the mode switching signal. IMAGE