ROM, EPROM, and EEPROM pdf tutorial

There is a type of memory for storing data in the absence of an electrical current, namely ROM (Read Only Memory), which is called read-only memory, sometimes a non-volatile memory because It does not clear when the system is turned off.

This type of memory makes it possible to preserve the data required to start the computer. Indeed, this information can not be stored on the hard disk since the parameters of the disk (essential to its initialization) are part of this data vital to the boot.

Overview

Read only memory devices are a special case of memory where, in normal system operation, the memory is read but not changed. Read only memories are non-volatile, that is, stored information is retained when the power is removed. The main read only memory devices are listed below:

• ROM (Mask Programmable ROM—also called 'MROMs')
• EPROM (UV Erasable Programmable ROM)
• OTP (One Time Programmable EPROM)
• EEPROM (Electrically Erasable and Programmable ROM)
• Flash Memory - This device is covered in Section 10

Table of contents

• HOW THE DEVICE WORKS
• MASK PROGRAMMABLE ROMs
• ROM Cell Size and Die Size
• ROM Programmed by Channel Implant
• Multimedia Card
• EPROM
• EPROM Floating Gate Transistor Characteristic Theory
• EPROM Cell Size and Die Size
• OTP (One Time Programmable) EPROM
• EEPROM
• Parallel EEPROM
• Serial EEPROM
• EEPROM Cell Program/Erase
• EPROM programming: Hot electron
• High VPP Current
• High ISUB
• VPP must be an external supply
• No VBB generator
• EEPROM programming: Tunneling
• VPP is generated by an internal pump