EEPROM Electrically Erasable Programmable Read-Only Remembrance

EEPROM stands for Electrically Erasable Programmable Read-Only Memory. EEPROM is a type of non volatile honour which is used in computers or electronic devices to maintain the data when influence is turned off on the other hand in occasion SRAM or DRAM facts may be lost when authority is switched off. To store the larger amount of data, a special type of EEPROM is used known as flash commemoration which is more economical in comparison to EEPROM devices. History :- In1983, George Perlegos developed the Intel 2816 at Intel, which was based on earlier technology EEPROM, nevertheless immediately we are using a thin gate oxide layer on account of the chip could erase its own bits without an ultra violet source. George Perlegos and others left to form Seeq Technology, which used on charge pumps devices to supply the high voltages which is necessary for EEPROMs. Types of EEPROM :- There are two types of EEPROM 1. Parallel Bus 2. Serial Bus Parallel Bus :- Parallel EEPROM devic
es typically have an residence bus wide enough to cover the complete recall and 8-bit data bus. Most devices have chip select (CS) and transcribe protect pins (WR). Some Microcontroller have integrated parallel EEPROM. Operation of a parallel EEPROM is simple and hurried in comparison to serial EEPROM, however these devices are larger due to the higher number of pins (28 pins or more) and have been decreasing in popularity in favor of serial EEPROM or Flash. Parallel EEPROMs are used in applications such as POS terminals, industrial controllers, LAN adapters, telecommunication switches, cellular phones and modems. Serial Bus :- Serial EEPROM works in three modes : OP-Code Phase, Data bus and Location Phase.The OP-Code is usually the first 8-bits input to the serial input pin of the EEPROM device followed by 8 to 24 bits of addressing depending on the depth of the device, then data to be discover or written. Serial EEPROM products are used in many applications to store
user reconfigurable data. Common applications are disk drives, modems, cellular phones, VCRs, CD players, hearing aids, PCMCIA cards, cordless phones, laser printers, computers and pagers. Comparison with EPROM and EEPROM/Flash :- EPROMs can not be erased electrically, and are programmed through hot carrier injection onto the floating gate. Erase is feasible with the advice of an Ultra Violet flare source, although in practice many EPROMs are encapsulated in plastic that is opaque to Ultra Violet light, and are "one-time programmable". EEPROM can be programmed and erased electrically using field emission generally known in the industry as "Fowler-Nordheim tunneling". Mostly NOR Flash retention is a hybrid style-programming is through hot carrier injection and erase with the aid of Fowler-Nordheim tunneling. Full text: http://computerandtechnologies.com/technology/news_2008-11-04-21-30-03-508.html