US Patent 7500171 Memory circuit

A memory circuit includes a data storage section for storing a plurality of data sets and a plurality of redundant data sets, which are used for error correction for the data sets; and an error correction section for performing at least error detection for the data sets in the data storage section by using the redundant data sets when the memory circuit is not accessed from outside for data input or output, and outputting at least result of the error detection as an error detection signal. When the memory circuit is accessed so as to output a designated one of the stored data sets, the designated data set is outputted without being subjected to the error detection by the error correction section.