The MSM6587 is a serial register in 524,288 words x 1 bit configuration featuring medium speed operation with low-power consumption. The MSM6587 has a built-in internal address generator circuit allowing continuous serial read/write operation by external clock input. The internal address is automatically incremented or decremented by one by read/write operation. Address increment or decrement can be selected by external input. Address designation in units of 1024 words in the direction of words is possible by an external serial address input.