CORRECTING CIRCUIT FOR TIMER INTERRUPTION

摘要

PURPOSE:To take an invariably accurate measurement of time by initiating a timer interruption to a CPU and measuring the elapsed time up to he response of the CPU by adding a counter. CONSTITUTION:An N-scale counter 5 initiates a timer interruption at a predetermined period T. An FF 6 generates an interruption signal and an interruption flag. An AND circuit 7 is an AND gate for clock generation which counts the number of times of interruption when an interruption response becomes longer than the period T. The contents of a binary counter 8 which counts the number of times of interruption are read in from an input port 9 in the interruption processing routine regardless of whether the time from the input of an interruption signal to the CPU 1 to the response by an interruption processing routine is longer or shorter than the period T determined by an oscillator 4 and the N-scale counter 5, thereby measuring the accurate time.