The semiconductor IC device for display control disclosed herein aims to achieve a higher rate of memory access cycles without enhancing the current carrying capability of the memory device. The IC device is provided with a memory cell array capable to store display data, peripheral circuits to enable writing and reading of display data, and a control circuit which is able to control read and write operations from/to the memory cell array. The memory cell array comprises a plurality of memory blocks. The control circuit comprises a control logic which enables parallel processing of write operations in such a manner that, before completion of writing of data to one of the memory blocks, writing of data to another memory block is started. Write cycles are shortened by the parallel processing of write operations.