| 摘要 |
PURPOSE:To reduce the write cycle by not correcting a word read by one address at write, storing words except the object one word in a register, inputting a write word and writing said information to the address together with an ECC bit generated corresponding to the obtained information. CONSTITUTION:A block 50 including a write object work 1 is read and the information of new ECC bit is decided from a new word '1' to be written and a word 2 of no correction. Thus, switches 62, 63 are turned to the position (b) at an address bit An, a word '1' of the input buffer 42 and a word 2 on a bus BS2 are inputted to a register 52 and the words are inputted to an EEC code bit generating circuit 33. The words 1'', 2 and the new ECC bit are written in the block 50 via buses BW1-3 and write amplifiers 21-23. At read, one of the corrected words 1', 2' is outputted via the ECC correction 31 and mis- detection 32. Through the constitution above, the write cycle is reduced and the peripheral circuit is simplified.
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