Graphic display systems having paired memory arrays therein that can be row accessed with 2(2n) degrees of freedom

摘要

A semiconductor memory device of a high degree of freedom in column and a graphics display system using the semiconductor memory device as a mapping memory are provided. The semiconductor memory device according to the present invention is comprised of a plurality of memory arrays and each memory array is comprised of a plurality of memory cell groups. A plurality memory cell groups in each memory array are independently selected according to the information of a separate column address. Column decoders select the column of a corresponding memory array in response to common column addresses and first or second separate column addresses. The first or the second separate column addresses select one memory cell group among memory cell groups in each memory array. The common column addresses select predetermined numbers of columns in each memory cell group.