What is EPROM??

EPROM is read only memory and can be programmed and erased. EPROM type of the most popular is the type of ultraviolet or UV EPROM. Once programmed electrically, the memory can be erased by means of lighting a high-intensity UV light.
On UV EPROM are quartz windows that allow UV light on the chip at the time of removal. These windows are covered by the opaque layer to prevent accidental deletion by a UV source that is usually only a small effect on the UV EPROM, but if the fluorescent lighting or sunlight on the chip in the long run it will cause loss or corruption of data therein . Model is the famous EPROM 27xxx series produced by the factory such as Intel, Advanded Micro Devices Inc. and Fujitsu Mikroelectronic. A description of some 27xxx models can be seen in Table 2-1. Everything is made with 8-bit output.

Table 1. Type EPROM and the ability bitnya For example IC EPROM 27C256 has 14 address pins A0-A13 and can produce 264,144 bits (214) possibilities in the memory. 27C256 EPROM using a 5 volt power supply DC and can be removed with UV light. Insert the chip enable (E) is low. Output enable pin has a dual function, which is the first time and second reading process during the writing process. Output pin 27C256 EPROM written Q0 - Q7. When the 27C256 EPROM erased all memory cells return to the logic 1 position. Data generated by changes in memory cells that have been chosen to 0. [1] (SGS-Thomson Microelectronik, March 1995)

Figure 1. Configuration EPROM M27C256 Description