Patent ID: 8402299

Claim:
An electronics device comprising: a time information acquisition unit configured to acquire time information representing present time from an external device; a reference time storage unit configured to store and hold reference time; an update unit configured to update the reference time stored in the reference time storage unit to a time represented by most recent time information acquired by the time information acquisition unit each time the time information is acquired by the time information acquisition unit; a counter circuit formed by hardware and configured to update its count value at fixed cycles; an elapsed time measurement unit configured to measure an elapsed time since the update of the reference time by use of the counter circuit; a present time calculation unit configured to calculate present time by adding the elapsed time measured by the elapsed time measurement unit to the reference time stored in the reference time storage unit; and a response unit configured to make the present time calculation unit calculate the present time and to output the calculated present time if a present time output request is issued.