| 摘要 |
PURPOSE: A microcomputer is provided to reduce the layout area of a chip by using a user's RAM as a storage for a test program without equipping a separate test ROM. CONSTITUTION: The CPU includes an old program counter(24) generating a program count value of a user's ROM(28) area and a new program counter(25) generating a program count value of the user's RAM(29) area in a test mode. The user' ROM stores a program that the CPU needs to control the entire microcomputer. The user's RAM stores the data generated in user mode and test mode, and temporarily stores the parts or entire data stored in the ROM. The CPU executes a test program by using a test vector stored in the user's RAM after stopping the operation of user mode by inactivating the user's ROM. After completing the test mode, the CPU converts into the user mode by activating the user's ROM.
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