From: jim bell <jimbell@pacifier.com>
Date: Sun, 16 Jun 1996 06:10:35 +0800
To: wxfield@shore.net (Warren)
Subject: Re: Fuseable Links - no guarantees??
Message-ID: <199606151810.LAA25519@mail.pacifier.com>
MIME-Version: 1.0
Content-Type: text/plain


At 01:46 PM 6/15/96 -0400, Warren wrote:
>Jim;
>
>        I was under the impression that a fuseable link was literally a
>piece of conductive material that you deliberatley 'blow-away' - In most
>cases, couldn't you simply 'tap into' the data side of the fuse, and
>download the info??

If it really is a "fusible link," that usually means a fuse, analogous to 
the much larger kinds used for circuit protection.  There are also 
"anti-fuses" which are high-resistance silicon links which on the 
application of a relatively high voltage, become low-resistance.

However, besides this, there is the typical EPROM-type cell, which can be 
programmed but not erased electrically.  (I'm ignoring cells like EEPROM 
which are designed and constructed to be electrically erased.)  As long as 
the chip contains most of its information in EPROM, that means that the chip 
was fabbed with a EPROM-compatible process, so they'd be more likely to 
include read-protection in EPROM as well.


Jim Bell
jimbell@pacifier.com