| 摘要 |
A highly reliable semiconductor device includes, for example, a memory circuit MEM such as a multiport RAM and a BIST circuit (BIST[A] and BIST[B]) for carrying out a test for each of the ports PO[A] and PO[B] of the MEM, as well as pointers PNT 0 [A] to PNT 3 [A] and PNT 0 [B] to PNT 3 [B] corresponding to the PO[A] and PO[B], respectively. Each of the BIST[A] and BIST[B] manages plural respective segments SEG 0 to SEG 3 obtained by dividing the MEM and the PNT 0 [A] to PNT 3 [A] are provided for those SEG 0 to SEG 3 , respectively. For example, the BIST[A], upon accessing SEG 0 , writes '1' in PNT 0 [A] while the BIST[B] refers to the value in this PNT 0 [A], thereby its access to SEG 0 can be avoided. Consequently, each port can execute a complicated test pattern asynchronously.
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