MEMORY BUS SWITCHING SYSTEM

PURPOSE:To remove complexity and dangerousness to be generated by a mechanical system or the like by automatically deciding the specification of a connected memory board, collectively switching an interface and selectively setting up a control signal. CONSTITUTION:The memory board 12 having an exclusive interface is provided with a flip flop 21 for holding an one-bit status signal at an 'L' level on a memory bus from a point of time immediately after resetting up to the start of access and a selector circuit 18 for selecting either one of a reference memory bus control circuit 15 and an exclusive memory bus control circuit 16 on a CPU board 11. The interface attribute of the connected memory board is decided by a CPU and a control signal for the interface is automatically switched to select and set up the control signal. Consequently, complexity and dangerousness like a mechanical setting case can be removed.