| 摘要 |
PURPOSE:To eliminate the unnecessary interruption to a secondary station CPU, by attaining a quick response with response information of a main storage device with a communication controller of the secondary station when the own secondary station is subjected to polling, in the polling of bus form. CONSTITUTION:The primary station applies the polling to a CPU12 of the secondary station via a bus 150 and an operating circuit section (communication controller) 22. The address of the polling is compared 71 and when the address is an address of own station device, the response information of a main storage device 32 is read out. When the secondary station has no information to be transmitted, since it is written in the response information, an EOT is transmitted 78 automatically. If the information to be transmitted exists, the interruption is applied to the CPU12 and transmits the information to the primary station. |
