| 摘要 |
PURPOSE:To prevent a central processor from malfunctioning by inhibiting a noise, generated wheh the power source of an external device connected to a bus driving device is turned off, from being sent to a bus. CONSTITUTION:When power source 17 of external device 13 is excluded, power break detecting circuit 18 in bus driving device 10 detects that and supplies a detection signal to NAND gate circuit 11. Therefore, signal S outputted from external device 17 is inhibited from being sent to bus 15. As a result, even if a noise is generated when the power source of external device 13 is excluded, the transmission of the noise to bus 15 is prevented, so that central processing unit CPU14 is prevented from malfunctioning owing to the noise. |
