| 摘要 |
PURPOSE:To reduce design work, to eliminate duplication in functions and to reduce the size of a chip by making ROM and RAM circuits into a single memory circuit. CONSTITUTION:Plural RAM cells RAC1 to RACn and a ROM cell ROC1 which reads stored data that are same as RAM cells are formed on a same column of a same chip. Plural word lines WL1 to WLn are provided corresponding to RAM cells RAC1 to RACn, respectively and when it becomes a selected level, the corresponding RAM cells are made into a selected condition. Digit lines DL1 and DL2 transfer unit storage data read from the selected condition cells among the RAM cells RAC1 to RACn and the ROM cell ROC1 and unit data to a RAM cell which is in a selected condition. A read circuit 2 outputs unit storage data, which are read out to the digit lines DL1 and DL2, to an external circuit. |
