| 摘要 |
PURPOSE:To shorten access time of a memory module by making an output control signal execute a write command of data of plural UV-EPROMs instead of an element selection signal. CONSTITUTION:Plural UV-EPROMM0-M3 are selected by an element selection signal of a decoder X1, and data writing is executed. When the writing is terminated properly, a program input terminal anti PGM and a supply terminal VPP of the ROMM0-M3 which are unnecessary for reading out by wiring modification are pulled up. Simultaneously, a chip select terminal anti CS of the ROM M0-M3 are commonly connected. At the time of reading out, the ROMM0-M3 are simultaneously selected, the decoder X1 sequentially acts in correspondence to an output control signal CE', and output control signals outputted from terminal antis Y1-Y3 are impressed to an output control terminal anti OE. Reading is executed by the output control signal outputted from the decoder X1 without delay and access time of a memory module is shortened compared with the case where wiring modification is not conducted. Moreover, its generation can be facilitated because of only wiring modification. |
