PURPOSE: To scale down the size of a chip, and to improve the efficiency of the design of a mask by frequency-dividing a timing clock by a plurality of flip-flops, inputting an output from the timing clock to a logic circuit section and driving an output buffer section by an output generated in a time division manner.
CONSTITUTION: Flip-flops 1∼3 frequency-divide a timing clock generated in a microcomputer. Outputs from the flip-flops 2, 3 are inputted to a logic circuit 4, and outputs are generated at output terminals for the logic circuit in succession in a time division manner. These outputs are inputted to output buffer sections 9∼12 through AND gates 5∼8. Outputs from these output buffer sections 9∼12 are each connected to the outside through external connecting terminals 19∼22. Currents flowing in from the external connecting terminals 19∼22 flow out to the outside from an external connecting terminal 24 together with the supply currents of other circuits through a Vss line 23 in a chip.
TERAI HARUO
MOCHIDA NORIHITO
| JPS53110360A | 1978-09-27 |