| 摘要 |
PURPOSE:To ensure a normal access to an electricslly rewritable nonvolatile memory despite the occurrence of abnormality of a power supply by having an access to a data storage part by means of plural state values stored in a state storage part. CONSTITUTION:A block which performs a reading operation is retrieved and it is confirmed whether there exist two same blocks (S10). When only one logical block is retrieved, the data are read out of this block (S11) and the processing ends. It is checked whether either one of both blocks has its state value '00' or not. If not, the state values of both blocks are compared with each other. Then the data are read out of the block that has the newer state value. If the state value is equal to '00', it is decided that the relevant block is kept in a reading state and the data are read out of the other block (S12). Then the processing ends. Thus the blocks can be normally read out. |
