de in which data is written onto the memory elements; FIGS. 5A to SI, and 6A to 6| show the waveforms of the signals applied to write and read data, respectively, upon the memory assembly as shown in FIGS. 3 and 4A and 48; FIG. 7 is a block diagram showing the arrangement of the memory assemblies as shown in FIGS. 3 and 4A, into a memory block and the arrangement ofa plurality of such memory block