| 摘要 |
PURPOSE:To shoren the communication processing time, by reducing the time, which is required for selecting a bus occupation request generated in each communication controller, to the half in the data transmission bus system. CONSTITUTION:A collating circuit MAT1 in each communication controller CCU collates a group number GN transferred from a bus controller BCU with peculiar group numbers held in a group number holding circuit GH; and when they coincide with each other, a coincidence detection signal I1 is outputted to make a gate G1 conductive. When detecting a group bus request signal RS1, a group bus request signal detecting circuit GD of the bus controller BCU stops a group number transmitting circuit GC and starts a device number transmitting circuit DC to transmit device numbers DN successively. A collating circuit MAT2 collates peculiar device numbers; and when they coincide with each other, a coincidence detection signal I2 is outputted to make a gate G2 conductive. When detecting a bus request signal RS2, a bus request signal detecting circuit RD stops the device number transmitting circuit DC. |
