The ST93CS66 and ST93CS67 are 4K bit Electrically Erasable Programmable Memory (EEPROM) fabricated with SGS-THOMSON's High Endurance Single Polysilicon CMOS technology. The memory is accessed through a serial input D and output Q. The 4K bit memory is organized as 256 x 16 bit words.The memory is accessed by a set of instructions which include Read, Write, Page Write, Write All and instructions used to set the memory protection. A Read instruction loads the address of the first word to be read into an internal address pointer.