| 摘要 |
PURPOSE:To obtain a storage device of prime memory type able to use five memory groups by adding one bit of a control signal and a selection circuit to an input section of a decoder. CONSTITUTION:A selector 4a has the 1st and 2nd input ports, the 1st output 2- bit of an ROM 1 is inputted from the 1st input port, ''11'' is inputted from the 2nd port and one input is outputted selectively. A selector 4b has the 1st and 2nd input ports, a 2-bit of a memory group selection signal is inputted from the 1st input port, a 2-bit of the 1st output of the ROM1 is inputted from the 2nd input port and one input is selected and outputted. The selectors 4a, 4b select the 1st input when the control signal ''0'' and the 2nd input when ''1'', and output it. Through the constitution above, it is possible to use the new memory group and five memories are used. |
