| 摘要 |
<p>PURPOSE:To make the capacity of a storage means enough to the capacity of a built-in I/O register only by accessing a storage means when the built-in I/O register is accessed. CONSTITUTION:A bus controller 2 receiving a bus status signal 6 of a microprocessor 1 and outputting an I/O read signal and an I/O write signal, a control signal generating means 10 outputting the I/O read signal of the bus controller 2, outputting a read signal when the I/O read signal of the microprocessor 1 is not outputted and outputting an I/O write signal when an I/O write signal of the bus controller 2 is outputted and the I/O write signal of the microprocessor is not outputted, and a storage means 4 controlling the read/write by the output of the control signal generating means 10 are provided. Since the storage means is accessed only when the built-in I/O register is accessed, the capacity of recording means is decreased.</p> |
