| 摘要 |
<p>PURPOSE:To simplify a processing software and to facilitate maintenance by directly handling the address of an I/O area in a sub-MPU with a main MPU, transferring this to the sub-MPU and making the I/O access to the sub-MPU. CONSTITUTION:A main MPU 1 sends the I/O address of an I/O device under the control of a sub-MPU 2 to make access to I/O processing from an interface part 3 to a cable 5 with an I/O instruction. An interface part 4 receives the transferred I/O address and applies the interruption to the sub-MPU 2. Thus, the sub-MPU 2 issues the I/O instruction with the I/O address by an interrupting processing and executes the access processing of the I/O area, for example, a port area 8 or 8'. At this time, at the time of the writing access, the written data are transferred from the main MPU 1 together with the I/O address, and at the time of the reading address, the read data are transferred from the interface part to the main MPU 1.</p> |
