Monday, January 30, 2012
9:29 PM No comments
EEPROM stands for electrically erasable programmable read only memory. It is a secondary storage device that once written (programmed) can hold data even when the power is removed. The EEPROM is a class of read only memory that can be electrically erased and reprogrammed.
AT24C02 is a two wire 2Kbits serial EEPROM by Atmel. The memory is organized in 256 words of single byte each arranged in 32 pages of 8 bytes each. The addressing of memory locations requires eight bit addresses.
AT24C02 is two-wire serially programmable i.e., for programming, the data and control signals are provided serially along with clock signals from the other wire. The read-write operations are accomplished by sending a set of control signals including the address and/or data bits. The control signals must be accompanied with proper clock signals.
The AT24C02 has hard wire addressing of 3 bit length. This facilitates interfacing of a maximum of eight (23) 24C02 devices to a system thereby, incorporating a maximum 16Kbits memory. Multiple 24C02 devices can be connected to a microcontroller/microprocessor based system using I2C interface.
The project demonstrates interfacing of a single 24C02 IC with AT89C51 (8051) microcontroller. The microcontroller is programmed to perform write operation of a single byte and read the same. The byte written and read is displayed on a LCD display.