Discontinued IC's

From: Clint Wolff <vaxman_at_uswest.net>
Date: Mon Jul 31 17:55:47 2000

On 31 Jul 2000, Eric Smith wrote:

> > To solve the problem, they
> > created VHDL, a complex language used to describe the behavior of the
> > parts, from the very high level to the very low. It does not detail any
> > of the internal structure of the chips - just behavior.
> Actually, VHDL can describe designs at any of several levels, including
> a range from pure behavioral, as you suggest, to pure structural.
> The most common uses of VHDL seem to be somewhere inbetween. Pure
> behavioral descriptions are fine for simulation but don't tend to work
> well for synthesis, so large designs are usually built as structural
> descriptions of smaller behavioral subdesigns.

Additionally, VHDL doesn't represent the actually layout of the chip
at all. Many times the netlist generated by the synthesis tool has to
be hand edited to fix up the last few timing problems. This is similiar
to hand routing a few traces on a PCB that the autorouter can't handle.

I have been wondering how difficult it would be to pop the top off
an ASIC (perhaps one of the DEC gate arrays in my 11/750), photograph
it using the probe station at work, and reverse engineer the circuitry
based on the photographs. A program to recognize individual transistors
wouldn't be too difficult, then generating simple gates (nand,nor,invert),
from them, the high level stuff like registers and busses...

Anybody know of a tool to do something like that?

Received on Mon Jul 31 2000 - 17:55:47 BST

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