JPS5576452A - Memory circuit - Google Patents

Abstract

PURPOSE:To realize a memory circuit which is effective to the test diagnosis by incorporating all bits of the memory circuit into the shift register route via the state designation signal. CONSTITUTION:State designation signal 21 designates whether the memory device should be used in the normal state or the shift state. And only in case the shift state is designated, address counter 23 advances its contents in synchronization with clock signal 22. And in case the shift state is designated, the data which is read out through reading circuit 25 and shifted by one bit plus the 1-bit shifted input data given from outside are supplied in the form of the writing date. Such writing data supply circuit is provided. Thus all bits of the memory circuit can be incorporated into the shift register route in the shift state. Thus a memory circuit which is effective to the test diagnosis can be obtained.