| 摘要 |
PURPOSE:To reduce a cost and number of steps by switching a command content stored in a ROM by an aluminum mask, and providing the ROM in which the stored content can be switched by the same mask as optional switching of a peripheral circuit. CONSTITUTION:A command memory (ROM) for storing commands, a central calculation processor (core CPU) for controlling various calculations and a peripheral unit by the output of the ROM, a data memory (RAM) for storing data to be processed by the CPU, input/output unit to be controlled by the output of the CPU, and a peripheral unit such as a counter, etc., are provided. The command content to be stored in the ROM is switched by an aluminum mask. For example, NMOS transistors T1-T5 are formed in intersections where N-type diffused F and polycrystalline X1-X5 are crossed. The transistors T1-T5 respectively store one bit of information, and store by a method of whether a source is connected to a drain via aluminum A or not. |
