| 摘要 |
PURPOSE:To make the detection of a data error caused by a hard error possible when performance tests are performed on a memory circuit and to make a soft error correcting function possible when the memory circuit is used by selectively setting ECC circuit functions to valid or invalid conditions through external control. CONSTITUTION:An ECC circuit function selection controlling means 6 is controlled by the detecting signal of a high-voltage detecting circuit 5 so as to selectively set the function of an ECC circuit 4 to valid or invalid. It can be exemplified as partical examples of the means 6 that a switching circuit which selectively controls the circuit connection between the ECC circuit 4 and a memory cell array 3 is provided, each of AND gate circuits 7, in which data of parity check results are inputted, is gate-controlled by means of an ECC circuit function selection controlling signal at a part of the ECC circuit 4, for example, at a corrected data implementing circuit 67, or fuse elements which selectively control the ECC circuit function in accordance with electrical fusion are provided on memory chips, and so forth. |
