| CPC G11C 16/22 (2013.01) [G11C 16/10 (2013.01); G11C 16/30 (2013.01); B60R 16/033 (2013.01)] | 18 Claims |
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1. A nonvolatile memory writing device wherein,
a nonvolatile memory writing device that writes write data transmitted from a microcomputer to a nonvolatile memory is provided outside the microcomputer,
the nonvolatile memory is connected to a power supply of the microcomputer, and is one in which writing of the writing data is protected and the protection is disabled by an electric signal from the microcomputer to a write-protect terminal of the nonvolatile memory,
the write-protect terminal is connected to a ground of a negative power supply side of the power supply of the microcomputer via a resistor,
when a voltage drop is detected by a monitoring function part that monitors the power supply, the electric signal from the microcomputer to the write-protect terminal is interrupted and an output from the microcontroller to the write-protect terminal becomes high-impedance, and the protection is disabled.
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