Easy 24C I2C Serial EEPROM Interfacing with AVR Microcontrollers

An EEPROM is kinds of novalatile memory, that means it is used for storing digital data permanently without any power suply. EEPROM stands for Electrically Erasable Programmable Read Only Memory. The advantage of these kind of ROMs is that they can be erased Electrically to make them ready for storing new data. Compare this with a CD R disks they
Easy 24C I2C Serial EEPROM Interfacing with AVR Microcontrollers - schematic

can be recorded only once. A small amount of EEPROM is also available internally on the AVR chips. So if the volume of data you want to store is small (say few user names and password) then you can use it. The internal eeprom makes design small and simple. But if the amount of data you want to store is large, say in order of few tens of kilobytes then you have to interface a External EEPROM chip with your AVR MCU. You can store pictures, sound and long texts in these eeproms. Their are many kinds of EEPROM chip available from many manufactures. One very common family is 24C series serial EEPROMs. They are available upto 128KB in size. They uses I2C interface with host controller (MCU) which is a very popular serial communication standard. I will write more indept tutorial on I2C in comming days and in this tutorial I will give you easy to use function that you can use without any knowledge of I2C interface. The chip has storage location which have their unique address ranging from 0-8191. Consider these as storage cells so while storing and retriving data you have to tell the chip which cell location you want to read. For exaple if you read location 0003 you will get 99 (see image above). Note each cell can store 8BITs of data so range you can store is 0-255 (-128 to +127). So if you want to store bigget data like int you have to store them in two cells. Connect your ATmega32 with 24C64 chip as shown in the circuit diagram....

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