| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a portable information equipment capable of preventing a write disable state caused by a decrease in a supply voltage that can occur during the reading of program data, and to provide a program rewriting method and a program. <P>SOLUTION: A voltage detector for detecting the voltage of a battery is provided in a cellular phone. An operation permission voltage VP in a program rewrite mode is set sufficiently larger than a drop voltage VD estimated in program rewriting operation, and is set as a value that is larger than a terminal voltage VE. When the voltage of the battery detected in the program rewrite mode is the operation permission voltage VP or larger, the program is rewritten. When the voltage of the battery is the operation permission voltage VP or smaller, program rewrite is prohibited. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
