Interface 24C01, 24C02, 24C04, 24C08, 24C16, 24C32, 24C64, 24C65, 24C128, 24C256, 24C512 8051 Microcontroller Family Models :
About Serial EEPROMs Overview And Tutorials
An EEPROM is the permanent storage devices and can be erased and reprogrammed whenever we need. These are the kinds of nonvolatile storage chip means when power is removed the content of the memory remains intact. It has no impact of power failure. EEPROM stands for Electrically Erasable Programmable Read Only Memory. The main advantage of this memory is that it can be erased and re programmed at any time. We can edit the content at particular location or remove the content from the particular location within the EEPROM chip. Example if you want to some security parameters or password or any kind of data which will be required by the embedded system then we need extra piece of hardware to get this job done. That is EEPROM. Here are so many EEPROM chips are available in the market by different reputed manufacturer but specially the most popular product if 24CXX series. All EEPROM uses I2C interface protocol to communicate with the 8051 microcontroller and vice versa. Serial EEPROMs typically have just eight pins power and ground, one or two data/address lines, and a clock input, plus up to three other control signals.
Various Models of Serial EEPROMs and Working
Serial EEPROMs are widely available in the market. From small memory size to huge memory size. Engineer use them as per the need in their applications. Here is the list some basic and used devices in the embedded industry. Thy are 24C01, 24C02, 24C04, 24C08, 24C16 I2C Bus EEPROM 24C32, 24C64, 24C65, 24C128, 24C256, 24C512 I2C Bus EEPROM 24XX EEPROM 24C325 and 24C645 I2C Bus. From all of the above only 24CXX is widely used and popular Serial EEPROM used by engineers and students. They are based on I2C Protocol where only two wires are needed for data communication and arranged as master and slave in the hardware where 8051 Microcontroller is the master and Serial EEPROM is the salve device. Which accepts commands from the Microcontroller and act according to them
Pin Description Of SERIAL EEPROM
Serial Clock In Pin (SCL): Pin No 6 the SCL pin means this pin will be used to send clock signals and synchronize with the device. Master is responsible for sending clock signal a slave can not generate clock signals.
Serial Data Out (SDA): Pin No 5 is the SDA pin means Serial Data can be accessed with this. This pin is used to send the address and receive the data from this. Same pin is used for both purpose for sending commands and receiving data at 8051 Microcontrollers end.
Hardware Device Identification/Page Address Pins: The most advantageous thing with I2C is that we can use multiple serial devices on the same line. Means one or more devices can share the same line for data communication. So Pin named A2, A1, A0 pin no 1,2,3 respectively on eeprom are the device address pins are used to identify the serial device on the chip. When and which device will be focused. These pins are used to specify that whichever device on the bus needs attention of the 8051 Microcontroller and will be ready for data communication
I2C Tutorials Of Serial EEPROM
Here are only two wires needed to read and write serial eeprom two wires, called SCL and SDA. SCL is the clock line where the device get clock signals. It is used to synchronize all data transfers over the I2C bus. SDA is the data line. The SCL & SDA lines are connected to all devices on the I2C bus. There needs to be a third wire which is just the ground or 0 volts.
Masters and Slaves
The devices on the I2C bus are either masters or slaves. The master is always he Microcontroller that start clock signal and sends commands to the serial eeprom and slave is the device that receive commands and act. The slaves are the devices that reply to the master. A slave device cannot initiate the transfer because it has no clock signal. One I2C line may have multiple serial eeprom attached.
Interfacing Serial EEPROM 8051 Microcontroller
Serial I2C (Inter-Integrated Circuit Bus) was developed by the PHILIPS to communicate with the slave devices soon it became popular all over the world and other manufacturer started manufacturing the devices on the same protocol. Connecting to the Microcontroller is very easy tasks only two wires are needed to connect the EEPROM device with the microcontroller SCL and SDA line can be connected with any two Pins of the Microcontroller. Here The circuit given is very simple to understand where SCL and SDA pins of the serial eeprom is connected with the P1.1 and P1.0 of the 8051 Microcontroller. Using any programming language we write a piece of code to run the application which is responsible for I2C communication. Here is the simple circuit. and very soon the code will be available which can be downloaded from right here at the free of cost.