Patent ID: 6046957
Filing Date: 2000-04-04
Classification: G11C

Abstract:
A semiconductor memory device with a flexible configuration, comprising:an M-by-N memory array having a number M of complete words, each of said complete words having a number N of bits, said memory array further having M word lines to address said M complete words, and N bit lines to access said N bits, wherein the number N has a number p of integer factors, said memory array being capable of being configured to operate in p different operating modes, where said bits of said complete words are rearranged into at least one sub-word formed as a bit group;a main address decoder connected to said word lines of said memory array and adapted to be connected to a main address bus, said main address decoder being adapted to decode main address signals on the main address bus and provide a number M of corresponding main address select signals to said word lines of said memory array, respectively;an input/output circuit includingan input buffer portion having a number N of bit writing units, each of said bit writing units having a buffer output terminal connected to a respective one of said bit lines of said memory array, a buffer input terminal, and a buffer enable terminal to control enabling of said bit writing unit for passing an input data bit at said buffer input terminal to the respective one of said bit lines via said buffer output terminal, andan output sense amplifier portion having a number N of bit sensing units, each of said bit sensing units having a sensing input terminal connected to a respective one of said bit lines of said memory array, a sensing output terminal, and an output enable terminal adapted to receive an output enable signal to control enabling of said bit sensing unit for sensing an output data bit of the respective one of said bit lines and for providing the output data bit at said sensing output terminal in response to an asserted state of the output enable signal;an auxiliary address decoder adapted to be connected to an auxiliary address bus and adapted to decode auxiliary address signals on the auxiliary address bus and generate a number N of corresponding auxiliary address select signals;a mode selector for generating mode control signals that correspond to a selected one of the different operating modes;an auxiliary address router connected to said auxiliary address decoder, said mode selector and said buffer enable terminals of said bit writing units of said input buffer portion, said auxiliary address router being adapted to receive a write enable signal and enabling appropriate ones of said bit writing units which are associated with said sub-word that is selected according to the auxiliary address select signals from said auxiliary address decoder and the mode control signals from said mode selector in response to an asserted state of the write enable signal;an input data router connected to said mode selector and said buffer input terminals of said bit writing units of said input buffer portion, said input data router being adapted to be connected to input data lines of an N-bit input data bus so as to receive input data bits therefrom and being adapted to route the input data bits from the input data lines that are selected according to the mode control signals to said appropriate ones of said bit writing units that are enabled by said auxiliary address router; andan output data router connected to said auxiliary address decoder, said mode selector and said sensing output terminals of said bit sensing units of said output sense amplifier portion, said output data router being adapted to be connected to output data lines of an N-bit output data bus and being adapted to route the output data bit at said sensing output terminal of appropriate ones of said bit sensing units, which are associated with said sub-word that is selected according to the auxiliary address select signals from said auxiliary address decoder and the mode control signals from said mode selector, to appropriate ones of the output data lines of the output data bus.