Nonvolatile semiconductor memory device using a command control system

Claim 1

An electrically programmable semiconductor memory device comprising: memory cell array means composed of electrically programmable nonvolatile memory cells; memory peripheral circuit means for specifying an address according to an external signal for said memory cell array means and performing an access operation; high-voltage supplying means for data program-related control of said memory cell array means; command register circuit means for supplying a command signal for performing a programmed operation to said memory cell array means according to an external control signal; command signal transfer means for controlling said memory peripheral circuit to perform at least one of a programmed and a reading operation on a given memory cell in said memory cell array means according to said command signal; nonvolatile protect memory means from which data is read whenever a programmed operation is performed on said memory cell array means; sensing means for supplying to said command register circuit means a control signal used when a programmed operation is performed on said protect memory means; protect sense amplifier circuit means for reading data from said protect memory means; protect control circuit means for controlling said protect memory means and said protect sense amplifier circuit means on the basis of the command signal from said command register circuit means; and control circuit means for controlling said high-voltage supplying means to control a programmed operation on said memory cell on the basis of the readout data from said protect sense amplifier circuit means.