The Microchip Technology Inc. 28C04A is a CMOS 4Knon-volatile electrically Erasable and ProgrammableRead Only Memory (EEPROM). The 28C04A isaccessed like a static RAM for the read or write cycleswithout the need of external components. During a“byte write”, the address and data are latched internally,freeing the microprocessor address and data busfor other operations. Following the initiation of writecycle, the device will go to a busy state and automaticallyclear and write the latched data using an internalcontrol timer. To determine when a write cycle is complete,the 28C04A uses Data polling. Data pollingallows the user to read the location last written to whenthe write operation is complete. CMOS design and processingenables this part to be used in systems wherereduced power consumption and reliability arerequired. A complete family of packages is offered toprovide the utmost flexibility in applications.