| 摘要 |
To provide a microcomputer which is improved to enable the functional selection of a functional macro and the characteristic correction without the mask option, trimming, and dedicated terminal and to quickly start the execution of the microcomputer. The microcomputer includes a main clock signal generating circuit and a ring oscillating circuit which generates a sub-clock signal that quickly enters a stable state. Initialized data is read from a flash ROM synchronously with the sub-clock signal, the read data is stored in a set data register, and a functional macro for the functional selection and characteristic correction is initialized. It is possible to end the setting of the functional macro for a clock stabilizing time necessary for the main clock signal. Further, it is possible to quickly execute the program by switching the signal to the main clock signal just after the clock stabilizing time.
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