TTL computing - test-drb@ccmp.vtda.org

12 Apr 2002

...
  -----Original Message-----
 From: ard(a)p850ug1.demon.co.uk [mailto:ard@p850ug1.demon.co.uk] 
...
  Here's how I'd do it (to make an 8 * 1 bit
fusible-fuse PROM).  
[snip]

...
  The way it works is like this. Normaly the Rd/Pgm
relay is in the Rd 
 state (as shown). In which case the sense relay is energised if the 
 selected fuse is intact. You can use the contacts of the 
 sense relay to 
 turn on/off a light bulb or something.  
Very close to what I imagined doing -- though, I hadn't gotten as far as
an address decoder. :)  Thanks.

...
  To blow a fuse, select it with the decoder tree and
then energise the 
 Rd/Pgm relay briefly. Enough current will flow via the 
 limiting resistor 
 to blow the selected fuse. When the Rd/Pgm relay returns to 
 the normal 
 position, there will no longer be a path to ground for the 
 bottom end of 
 the sense relay, so this relay will not be energised. 
Again -- a good plan.  I was thinking about using a momentary switch
for programming anyway, rather than anything more complex, so that 
fits exactly with what I wanted.

...
  I am going to _have_ to make one of these just for
fun.... 
I'm glad that I'm not the only one crazy enough to consider trying it.

Chris

Christopher Smith, Perl Developer
Amdocs - Champaign, IL

/usr/bin/perl -e '
print((~"\x95\xc4\xe3"^"Just Another Perl
Hacker.")."\x08!\n");
'