PURPOSE: To enable to select securely whether an execution start signal depends upon an external operation start signal or operation contents indication signal through the simple circuit constitution of a memory circuit, chattering eliminating circuit, operation signal generating circuit, etc.
CONSTITUTION: When selection signal FN has level "1" and some of operation contents indication signals PSn-1WPS0 change "0" W "1" simultaneously, chattering eliminating circuit 7 outputs strobe signal CF a certain time later. Operation start signal generating circuit 5 outputs load signal IT at the leading edge of input signal CF. Memory circuit 6 stores signal PSn-1WPS0 inputted to data input terminals In-1WI0 at the leading edge of signal IF, holds them until signal CF is generated again, and performs the operation that corresponds to the operation contents indication signal. On the other hand, when signal CF is held at "0", circuit 5 outputs signal IT at the leading edge of external operation start signal ST. Circuit 6 stores the input operation contents indication signals and performs the operation that corresponds to the operation contents indication signals until signal ST is inputted again.
IRIMICHI TOMOAKI
KAWASAKI ITARU
