Portable information processor having password code checking function

摘要

Switching between a requiring mode and a non-requiring mode of password code checking is enabled by an IC card with a CPU for accessing an EEPROM. The general data in the EEPROM are stored upon attachment of error check codes. The memory area of EEPROM is partitioned into unit areas of 2-byte length and writing is performed according to unit areas. The MSB of a specific unit area Ux is used as a checking requirement flag with "1" being defined as checking "required" and "0" being defined as checking "not required". In rewriting the checking requirement flag, an erasure process sets all bits in the unit area Ux to "1" and thereafter the desired flag is set in the MSB.