| 摘要 |
PURPOSE:To use a peripheral equipment always with the same address even when the peripheral equipment is connected to any bus by executing control so that a gate can be made open a gate to pass through or cut-off data from an external bus, to which the peripheral device is connected to execute an access to a gate control means and the other gate is caused to be closed when the access is executed to the peripheral equipment with a microprocessor. CONSTITUTION:Gates 5A and 5B are provided between respective external buses 6A and 6B and an internal bus 4 to allocate a usable address to the plural external buses 6A and 6B with overlapping it, to pass through or cut-off the data and to be normally opened to pass through the data. When the access is executed to a peripheral equipment 7 by a microprocessor 1 and the data are read, a gate control means 8 is provided to execute the control so that the gate 5A, which is between the external bus 6A connected to the peripheral equipment 7 to which the access is executed and the internal bus 4, can be made open and the other remained gate 5B can be caused to be closed. Since only the data from the peripheral equipment, to which the access is executed, is passed through the gate and sent on the internal bus at the time of a data reading, the peripheral equipment can be used always with the same address even when it is connected to any bus. |
