Memory control device and memory control method

Abstract

A memory control device includes a CPU 1, a flash ROM 4 that records therein first information having undergone an error-correction coding process and second information not having undergone an error-correction coding process, an address line switch 5 that switches between a first path that connects an address bus 2 to the ROM 4 so that the CPU 1 can read the first information recorded in the ROM 4 and a second path that connects the address bus 2 to the ROM 4 so that the second information recorded in the ROM 4 can be erased, written, and read, a decoder 7 that performs error correction on the first information recorded in the ROM 4 and performs decoding, and a second switch 6 that switches between a third path that connects the decoder 7 to the data bus 3 so that information decoded by the decoder 7 is transmitted to the data bus 3 and a fourth path that connects the ROM 4 to the data bus 3 so that the second information recorded in the ROM 4 can be erased, written, and read.

Description

technical field [0001] The present invention relates to a memory control device and a memory control method using an electrically rewritable nonvolatile memory (“flash ROM” or “EEPROM: Electrically Erasable Programmable ROM”). Background technique [0002] In recent years, a flash ROM is generally mounted as a recording medium for an operating system (OS), application software, and the like in a memory control device that performs various controls by a CPU (Central Processing Unit). This flash ROM has the following features. (1) The data is retained even when the power is turned off. (2) Before writing data, it is necessary to erase the writing area. (3) Data erasure needs to be performed in predetermined block units for each device, and is performed by supplying signals in steps specified by the data pins of the device. (4) Writing of data is carried out by supplying signals according to the procedure specified by the data pin of the device. [0003] However, this flash...

AI Technical Summary

Problems solved by technology

[0003] However, this flash ROM is configured to record data values ​​by confining electric charge into the device, so a phenomenon called "leakage" may occur due to variations in the data retention time of each memory cell, the influence of noise, etc.

Images