Dual port RAM

摘要

A dual port RAM includes an any-time readable/writable memory block in which an access can be made to the same storage area from independent first and second ports. In addition, the RAM includes a first test circuit for performing a test to the storage area of the memory block via the first port on the basis of a first clock signal, and a second test circuit for performing a test to the storage area of the memory block via the second port on the basis of a second clock signal. A control circuit of the RAM causes the first and second test circuits to test the memory block in an alternating manner.