| 摘要 |
PURPOSE:To provide the CPU board capable of switching access at high speed. CONSTITUTION:When an extended device is accessed, a gate control signal is turned to an 'L' level and outputted to a gate control line 34 by a switching control circuit 48. Thus, since the gate of an AND circuit 38 is closed, a control signal outputted from a CPU 2 and required for access is not applied to an object equipment. Therefore, only the extended device is accessed. On the other hand, when the object device is accessed, the gate control signal is turned to an 'H' level and outputted to the gate control line 34 by the switching control circuit 48. Thus, since the gate of the AND circuit 38 is opened, the signal of an in-board control line 32 is outputted to a plug 14 as it is. Namely, the control signal outputted from the CPU 2 and required for access is applied to the object device. |
