CLOCK FUNCTION OF MICROCOMPUTER

摘要

PURPOSE:To eliminate the need for reset of a clock at power interruption by providing a phase signal circuit generating a pulse signal while using a commercial electric power supply normally and a transmission signal using the frequency of the same power supply having the same oscillating period as an oscillating frequency. CONSTITUTION:The oscillation signal X of an oscillation circuit 2 has the same the oscillating frequency as the power frequency similarly as a phase signal PS outputted synchronously with the commercial power supply 8 from the phase signal circuit 4. If the power is interrupted, before the phase signal circuit is operated normally, a selection circuit 3l uses signals D1, D2 to detect the interruption of power supply and the oscillation signal X of the oscillation circuit 2 is used as a new reference signal S in place of the signal PS. When the power supply is restored, the signal PS is used as the reference signal again and transferred to a microcomputer through the operation above.