| 摘要 |
PURPOSE:To reduce the number of output terminals, etc., and to make a titled unit small in size and low in its cost by constituting an outputting circuit of a tri-state circuit, connecting in parallel plural outputting circuits, and using an output connecting part in common. CONSTITUTION:Logic parts LG1-LG4 are formed by data latching circuits 81- 84 of eight bits and driving circuits 91-94, and an output unit OU' is constituted by providing this part by plural (four) pieces. The data latching circuits 81-84 select the data latching circuit concerned by an address signal AD, store a data DL, and send it out to a tri-state circuit 11 through the driving circuits 91-94 and an output isolating circuit 10. Selective input signals CH1-CH4 are sent out to said latching circuits 81-84 through electrically insulated input isolating circuits 121-124, and also said data is outputted to the corresponding terminal part by an inable signal INB passing through an OR gate 13. |
