| 摘要 |
PURPOSE:To reduce the number of parts by attaining conventional ROM and EEPROM functions only by a flash EEPROM. CONSTITUTION:The flash EEPROM 145 is divided into four blocks 1 to 4 and a rewriting program, control information and a system program are stored in respective blocks 1 to 4. The control information is duplexedly stored in both the blocks 2, 3. Thereby even when power supply interruption or any other error is caused during the updating of one erasing block, the control information of the other erasing block is normally held. Since control information in a valid information is read out, normal control information can be utilized. Thus the control information can be prevented from being destructed and conventional ROM and EEPROM functions can be attained only by the flash EEPROM 145. |
