Digital Systems: Principles and Design

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Digital Systems

During read operation, the V

DD

and

V

SS

are the supply inputs in EPROM chip and are at

5 V and GND, respectively.

An IC E

2

PROM can be erased as well as programmed like (2k ´ 8) 2816 without an

exposure to UV light. We call such EEPROM; electrically erasable and programmable read

only memory i.e. E

2

PROM. These E

2

PROMs, in case possess a short access as well as pro-

gramming time and has full erasibility in one cycle then are called flash memories, for ex-

ample, an E

2

PROM IC 28F256 is a flash memory. (F in an IC number of a ROM denotes a

flash memory).

E

2

PROM is erasable and programmable above 10000 (in latest E

2

PROMs) times by the