| 摘要 |
PURPOSE:To reduce the number of driver circuits in an I/O device by forming plural channels for counting up addresses in a memory and outputting a channel specifying signal at the transfer of data. CONSTITUTION:A CPU sets up a leading address in a counter having a presetting function and then sets up a channel No. of a memory to be used in a channel register of a register part 41' of an I/O control device 4. Obtaining a bus using right, the control part 41' outputs a channel address signal and a control signal. The memory discriminates these signals, validates an address gate signal corresponding to the channel concerned and reads out and outputs the data to a bus 3. The control part 41' enters the data on the bus 3 into a register part 42', transfers the data to an I/O device 5 and counts down the number of transfer words in a command register of the register part 42' by '-1'. A series of operation is executed until the number of transfer words in the command register is turned to zero. |
