At 05:19 PM 19/05/98 +1000, you wrote:
>On Tue, May 19, 1998 at 01:15:18AM -0400, Ricardo Ponte G wrote:
>> 
>>         "PICmicro FLASH device" so, what«s the mean of " FLASH device " 
>
>It's a device that indecently exposes itself :-)
>
>Seriously, FLASH is a fancy term for a kind of electrically-erasable
>programmable read-only memory (EEPROM). The exact difference between
>FLASH and regular EEPROM depends on which marketing person you talk to,
>but basically FLASH is always bulk-erased, whereas (some) EEPROM can be byte
>erased.
>
>I think the original term came from the fact that it can be erased in a flash.
>
>Cheers, Clyde
>
>-- 
>Clyde Smith-Stubbs               |            HI-TECH Software
>Email: clyde@htsoft.com          |          Phone            Fax
>WWW:   http://www.htsoft.com/    | USA: (408) 490 2885  (408) 490 2885
>PGP:   finger clyde@htsoft.com   | AUS: +61 7 3354 2411 +61 7 3354 2422
>---------------------------------------------------------------------------
>HI-TECH C: compiling the real world.
>
>

Clyde is right, however the difference can be expanded somewhat more. A
FLASH device must have all the bits set to 1 i.e. FF as it can only clear
the bits in the macrocell i.e. wrtie a 0 to it (During programme), whereas
an EEPROM can change the state of any bit. Also the FLASH device has 4 gates
per memory cell, whereas; an EEPROM has 6.


Dennis


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Dennis Plunkett: Embedded Hardware, Software design
NEC Australia DRMASS
Line Interface cards
TRX software
ISDN interface card
ph 03 9264-3867

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