I/O DEVICE, I/O DEVICE CONTROL METHOD, STORAGE MEDIUM STORING I/O DEVICE CONTROL PROGRAM, I/O DEVICE MOUNTABLE ELECTRONIC DEVICE AND ELECTRONIC DEVICE CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To decrease the harmful effect of a 2nd operation mode by switching a signal line which is not used in the 2nd operation mode to a 3rd operation mode when the number of working control signal lines of the 2nd operation mode is smaller than that of a 1st operation mode. SOLUTION: When the number of working control signal lines 104 of a 2nd operation mode (True ID mode) is smaller than that of 1st operation mode (PC card memory mode or PC card I/O mode), the 1st operation mode is shifted to the 2nd operation mode and then the 2nd operation mode is shifted to the 3rd operation mode (USB mode) by using a signal line 104 that is not so significant in the 2nd operation mode. Thus, the operation mode of an I/O device 101 is switched. As a result, the addition of new signal lines 104 is not required and the possibility of hurting the 2nd operation mode can be reduced.