A dual-port memory controller having a memory controller and at least one delaying
unit. Since the memory controller executes a data access by selecting one processor,
the memory controller outputs at least one request disapproval signal indicating
that it cannot accept data access requests from other processors. The delaying
unit includes a clock oscillator, and flip-flops receiving the clock signal and
delaying the request disapproval signal. The delaying unit varies the delay time
by varying the clock frequency of the clock oscillator. The memory controller executes
data access to the same memory area after a predetermined period of time elapses,
so processors can read/write stabilized data.