| 摘要 |
<p>PURPOSE:To prevent the errorneous calibration of the time value of a software timer by reading the time value from a storage means when a reference clock is inputted, subtracting a normalization value from the time value, obtaining an error value and setting the normalization value in the storage means when the value of the error value is within a prescribed range. CONSTITUTION:A counting means 10, a normalization means 11 and a calibration means 12 are included in CPU 1. A frequency divider 3 frequency-divides a clock, generates the real time clock of 100 Hz and inputs it to the interruption terminal of CPU 1. A reference clock oscillator 4 generates the reference clock of 1Hz and inputs it to CPU 1. When the reference clock is inputted, the time value is read from a memory 5, a normalization processing is executed as against the time value and the normalization values is obtained. Then, the normalization value is subtracted from the time value so as to obtain the error value. Then, the values of the error value is decided to be within the prescribed range or not. When it is within the prescribed range, the normalization value in the memory 5. Thus, the time value is prevented from the being errorneously calibrated.</p> |
