| 摘要 |
PURPOSE:To unify all data in the forward direction by securing such a constitution where a bit order switch means is controlled by the permission signal applied to a prescribed bus master circuit from a bus arbiter circuit and changes the transfer signal into the forward or reverse direction when an access is given to a memory from said bus master circuit. CONSTITUTION:When data are set into a bus master circuit 12, the data delivered from a CPU are supplied to a bit order switch means 11 via a bus 15. Then the data are supplied forward to the circuit 12 through a terminal (a) since no permission signal is received from a bus arbiter circuit 10. In case an I/O device 13 serves as a communication device which transmits the image data and the circuit 12 serves as a communication controller, the means 11 turns the forward data into the reverse one to send this to the device 13 as long as the permission signal of a permission signal line 101 is received. Thus it is not required to perform the extra bit order converting processes before and after the data processing operation. Then the working efficiency is improved for a memory access control system. |
