| 摘要 |
<p>PROBLEM TO BE SOLVED: To make the time of timer coincident with standard time with high accuracy corresponding to time information from the outside and to eliminate trouble caused by the discontinuity of time that occurs in case of time correction. SOLUTION: The transmission frequency of oscillator 2 is controlled by the output voltage of voltage selector circuit 5. A subtracter 6 subtracts a value (b) of timer counter 1 from a value (a) of timer setting register 3 and sets (a-b) to a correction counter 7. An ALL'0' detection circuit 9-1 detects all '0' of correction counter 7. When the result of comparator circuit 4 shows a>b, first of all, the voltage selector circuit 5 selects the voltage of H level and next, since the correction counter 7 is not ALL '0', the H level is outputted to the oscillator 2 as it is. Then, the signal of frequency higher than standard is impressed through the timer counter 1 and a count control circuit 8 to the correction counter 7 and counting at the timer counter 1 is fastened. When the correction counter 7 becomes '0', the output of voltage selector circuit 5 is turned into N level by the output of ALL'0' detection circuit 9-1 and the output of oscillator 2 becomes a standard frequency.</p> |
