LOGIC CIRCUIT DESIGNING DEVICE

PURPOSE:To visually grasp the action of a data bus and to prevent the designating mistakes to the action of the data bus by designating a valid bus and the mode of a computing element contained in the valid bus and deciding the working of the data bus for automatic synthesization of a control circuit. CONSTITUTION:A computer 1 outputs the data bus part of a circuit to a picture output device 3 based on the net list data 2. When a valid bus is designated on a screen by a pointing device 4, a subject valid bus is inputted to the computer 1. In this case, the valid bus means such a bus that is selected by a multiplexer when the circuit is acting. Then the input signal of a control circuit is applied via a keyboard 5 and the control circuit is automatically synthesized. Thus a designer is not required to perform the complicated logical design of the control circuit. As a result, the software designing period and labor can be extremely reduced.