Method for operating a semiconductor memory device having a plurality of operating modes for controlling an internal circuit

Abstract

Signals supplied to predetermined terminals are accepted as commands at a plurality of times, the number of operating modes is sequentially narrowed down based on the command each time and an internal circuit is controlled according to the narrowed operating modes. Since the information necessary for determining an operating mode is accepted at a plurality of times, the number of terminals necessary for inputting commands can be reduced. In particular, in case of inputting commands at a dedicated terminal, its input pads, input circuits, or the like are no longer be required so that the chip size can be reduced. The reduction is accomplished by reducing the number of terminals, which gives limits to the package size. The command controlling circuit with a plurality of accepting circuits is comprised. Each of the accepting circuits respectively accepts signals, supplied at a plurality of times, each time. In other words, in accordance with the timing of the signal supplement, a different accepting circuit is respectively operated and the internal circuit is controlled. Accordingly, a command controlling circuit may be readily designed even in the semiconductor memory device having a complicated command combination. Consequently, it is able to facilitate the verification of the design.