Tanaka Takaharu, Maenobu Kyoshi, Yoshioka Kosuke, Hirai Makoto, Kiyohara Tokuzo: Processor capable of efficiently executing many asynchronous event tasks. Matsushita Electric, September 9, 1998: EP0863462-A2 (33 worldwide citation)

The counter 52 is set with an initial value of "1" and is a counter with a maximum value of "4". This counter 52 increments the count value held by the flip-flop 51 in synchronization with a clock signal so that the count value changes as shown by the progression 1,2,3,4,1, 2,3,4. This clock signal ...