| 摘要 |
PURPOSE:To add a perpetual calendar function to a one-chip microcomputer by obtaining the passed data from the value of a simple binary counter for calendar obtained when a power supply is cut off and the value of said binary counter obtained when the power supply is applied and obtaining the present data by calculation. CONSTITUTION:A time piece function circuit block 6 which receives a back-up power supply 14 is always working and a central arithmetic processing part 1 is actuated in a normal working state where a main power supply 13 is applied. Then the present data is calculated for each unit time based on the output of a timepiece counter 62 of said block 6. When the power supply is cut off, the data when the power supply is cut off is written into a memory part 4 together with the value of a simple binary counter 63 for calendar of the block 6. When the power supply is applied, said data and counter value are read out of the part 4. Then the passed data is calculated from the value of the simple binary counter for calendar obtained when the power supply is cut off and the value of the counter obtained when the power supply is applied to calculate the present data. |
