| 摘要 |
PURPOSE:To facilitate the setting of an address space and realize economical constitution by adding a setting circuit for a starting address and also providing a setting circuit for setting an ending address. CONSTITUTION:A decision making circuit 7 makes a comparison and decide that the address on an address bus 2 is between a starting and an ending address signal specified by the setting circuits 3 and 6, and then supplies an output signal 7a to a selecting circuit 5. The selecting circuit 5 selects a memory, i.e. some memory chip corresponding to the address allocated in the memory device 1 according to the output signal 7a and address signals. Thus, both the starting and ending addresses of the memory device are set, so even when an RAM and an ROM of fixed size are set before and after the memory space, address setting is performed freely and the number of cards of the device is reduced to reduce the space and power source capacity. |
