ROM type devices retain their stored data even after losing power. The data is either hard coded into the device during manufacture, or programmed in later (PROM) via a special programming device. Some types of ROM can be programmed, erased, and re-programmed with new data. (EPROM, EEPROM, FLASH).
The key thing to know about any EPROM, OTP, EEPROM, flash memory, etc. is the operation principle.
All of the above mentioned types work by building up a charge on a MOSFET gate structure. Once the charge is built up during programming, it is stranded there by electrically isolating the gate. This is one "bit", represented by either some charge or no charge, depending on the design.
Since all these types use the same storage principle, they are theoretically about equal in terms of robustness.
The main difference between the technologies:
1) EEPROM and flash let you bleed off the charge via electrical erasure. EPROM requires UV light to bleed off the charge.
2) EEPROM bytes are individually programmable/erasable, whereas flash is programmable/erasable only in bulk or in blocks.
3) OTP is just EPROM without the UV window, so you can't erase it.
|file: /Techref/mem/roms.htm, 1KB, , updated: 2017/2/5 13:22, local time: 2018/10/16 02:15,
|©2018 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?|
<A HREF="http://www.piclist.com/techref/mem/roms.htm"> Non-Volatile (ROM) memories</A>
|Did you find what you needed?|
PICList 2018 contributors:
o List host: MIT, Site host massmind.org, Top posters @20181016 RussellMc, Van Horn, David, Sean Breheny, David C Brown, Bob Blick, Neil, Isaac M. Bavaresco, John Gardner, Harold Hallikainen, Denny Esterline,
* Page Editors: James Newton, David Cary, and YOU!
* Roman Black of Black Robotics donates from sales of Linistep stepper controller kits.
* Ashley Roll of Digital Nemesis donates from sales of RCL-1 RS232 to TTL converters.
* Monthly Subscribers: Gregg Rew. on-going support is MOST appreciated!
* Contributors: Richard Seriani, Sr.
Welcome to www.piclist.com!