Counter control apparatus and control method thereof

A counter readout control apparatus comprising a plurality of counters, in which each upper-order counter performs a counting operation upon receiving a carry signal from a lower-order counter, and a plurality of flag storing memories, each said flag storing memory storing a carry signal from a counter, with an exception of an uppermost-order counter, said apparatus further comprising:

• a first means for resetting each said flag storing memory,
• a second means for sequentially reading out said plurality of counters from an uppermost-order counter to a lowermost-order counter,
• a third means for, after reading each counter value by means of said second means, testing as to whether each said carry signal is set or not in each said flag storing memory, and
• a fourth means for, in the case in which one of said carry signals is set in one of said flag storing memories, resetting said flag storing memory having said set carry signal and performing a re-read operation only of counters having an order higher than an order of a counter which has been changed due to a reception of said carry signal.