| 摘要 |
PURPOSE:To prevent a through-current between bus drivers by fixing the bus driver of an output of all function blocks at the change point of the input of a selection signal of the bus driver to one and same logic level. CONSTITUTION:An AND circuit 4 receiving a signal from a control input terminal 1 and a signal input terminal 2, an AND circuit 5 receiving a signal from the control input terminal 1 and a selection signal input terminal 3 and a tri- state circuit 6 receiving an output of the AND circuit 4 as the signal input and an output of the AND circuit 5 as a selection signal input constitute the title circuit. While the control input signal is at 'L' level, the content of the bus is at an 'L' level and the content of a function block is outputted for a period when the control input signal is at an 'H' level. Since the control input signal is operated at a change in the selection signal input and the output of the tri-state circuit 6 is brought forcibly into the 'L' level while the selection signal input and the signal input are made stable, the through-current between the bus drivers is prevented. |
