EEPROM Full Form

Introduction

EEPROM is Electrically Erasable Programmable Read-Only Memory, it is a non-volatile memory chip, used in computers, microcontrollers, and remote systems. It allows small bytes of data to be stored, erased, and reprogrammed. This article covers everything about Electrically Erasable Programmable Read-Only Memory, also called EEPROM. This article covers the necessary reason for the invention of EEPROM and the different memory interfaces of EEPROM. 

Origin of EEPROM 

EEPROM was developed from the standard technology of EPROM, which is most widely used in the late 1970s. Data is stored in EPROM memory chips, which is mostly machine software; it is later erased by exposing the chip to UV light if the software needs to be changed. This erasing process nearly takes an hour, and this was acceptable for development environments. These memories could not be erased electrically, and an electrical arrangement to erase these memories would be more convenient.

 In 1983, Intel developed a technology, modifying the existing technology EPROM. With the same attributes of EPROM, EEPROM is developed in which memory can be erased and written again electrically. The first EEPROM device to be launched was Intel 2816.

Later many experienced EEPROM developers from Intel dropped and started their own company named Seeq.

Electrically Erasable Programmable Read-Only Memory (EEPROM)

EEPROM is a type of semiconductor chip, which is a non-volatile memory used to store small data. These stored data can be erased and reprogrammed. To erase data, high voltage is required and EEPROMs produced back then, required high voltage.

To those who have experience with RAM, EEPROM is much slower compared to it, while erasing and writing. So, the data is stored in EEPROM memory, such that it does not affect the operation of the overall system. In EEPROM the erase and write operations are done on a byte per-byte basis. EEPROM uses the same technology used by EPROM memory. Even though the memory cell configuration differs, the basic idea behind every memory cell is similar.

The memory cell has two transistors that are field effective:

·   Storage transistor

·   Access transistor

Storage transistor:

A storage transistor is also called a floating gate. Electrons are stored in this gate, the number of electrons that are present or absent in this gate determines the data that has been stored.

Access transistor:

Access transistor takes care of operational aspects of the memory cell.

EEPROM’s serial and parallel interface

EEPROM uses serial and parallel interfaces for data input and output. The actual method in which the memory device is used depends on the memory type and its interface.

Serial EEPROM memory:

The most commonly used serial interfaces are Microwire, I2P, SPI, and 1-Wire, UNI/O. The serial EEPROMs are difficult to operate, as data is transferred in a serial fashion, this makes the process much slower than their parallel EEPROM interface.

An EEPROM serial protocol has three phases: OP-code phase, address phase, and data phase.

Every EEPROM device has its own set of OP–code instructions connected to different functions. Common operations performed by Serial Peripheral Interface EEPROM devices are:

·   Read Status Register (RDSR)

·   Write Status Register (WRSR)

·   Write enable (WRENAL)

·   Write disable (WRDI)

·   Read data (READ)

·   Write data (WRITE)

Some other operations which can be performed by EEPROM devices are:

·   Program

·   Sector Erase

·   Chip erase

 Parallel EEPROM memory:

EEPROM devices, which are in parallel have an address bus and an 8-bit data bus, which covers the entire memory. These devices have chip-protect pins. Microcontrollers use parallel EEPROM. The operation of Parallel EEPROM is simple and efficient. Parallel EEPROM is faster compared to serial EEPROM, but the size of these devices is huge because of the large pin count, nearly 28 pins, so it has been used less, and serial EEPROM is used. Flash memory has better performance at a similar cost to EEPROM, while serial EEPROM offers a small size.

Disadvantages of EEPROM

There are two major limitations in EEPROM, one is reliability. Due to this reason, EEPROM is used less, as other memory devices provide better reliable memory storage. Limitations of EEPROM

·   Data Endurance

·   Data Retention

Conclusion

EEPROM is a type of ROM that can be erased and written. This can regain memory even without power. It is reprogrammable and cost-effective. The data inside the chip can be erased and reprogrammed any number of times. The time that is taken to erase data is between 5 to 10 milliseconds. Compared to other memory units, in EEPROM a particular byte of data can be erased and written, without deleting the entire memory unit.