Semiconductor memory device with redundant memory and floatable data line

A semiconductor memory device comprising:

• output means for transmitting an input signal to an external circuit;
• data bus means for transferring an input signal to said output means;
• first means for storing arbitrary data and reading out the stored data at an arbitrary time, said first means comprising:
• normal memory means for storing said arbitrary data and reading out the stored data at said arbitrary time;
• redundant memory means for substituting for a memory area in the normal memory means which has a deficient memory cell;
• and
• normal/redundant selector means which normally outputs data read from the normal memory means and, when the deficient memory cell is addressed, outputs data stored in the redundant memory means, said normal/redundant selector means having a redundant address memory means for storing said deficient memory cell addresses the normal/redundant selector means delivering the output data to said data bus means which if different than said redundant address memory means, as an output of the first means,
• second means for storing internal information of the first means, said second means having code storing means for storing a fixed code representing said internal information, connected to the data bus means between the output of the normal/redundant selector means and the output means, said code storing means being operable in two modes in accordance with a first external signal, wherein in a first mode, said code storing means is disconnected from said data bus means, thereby allowing the output of the first means to be transferred to the output means without having any delay caused by the code storing means, and in the second mode, said code storing means delivers said fixed code to said data bus means.