Re: Are chips more vulnerable to witchcraft than transisters?

On Fri, 6/19/2026 8:40 PM, phoenix wrote:
> Paul wrote:
>> When the things they do, are closer to being software
>> subroutines (adhoc state machines and so on), it's a lot
>> easier to make mistakes. One chip had 4096 registers in
>> the interface, and we would make a software program to
>> "watch" the register contents. There were some "defined"
>> parts of the registers, we could understand what those
>> were doing. But you would see some other addresses where
>> the detail of the chip was "undefined" and these were observation
>> points and stuff was flashing on and off. That's what the
>> more "random" functions look like. The people at the other
>> company who made the chip, knew what they did, but they
>> don't have to document those observation points for other
>> to use. It took about four tries,
> 
> You made a grand spelling error in that sentence. It should say, "for others to use." What I see is that you are irresponsible and probably going to electrocute yourself to death. Don't play with electricity. Bad juju all around.
> 

This is a CMOS chip, likely running at 3.3V, and we're watching
the interface using a display program written for the OS. The
prototype chip is mounted on a card, for these first runs. It's
an I/O type chip full of state machines and junk. It's hard to get
a handle on what it's doing when it has 4096 registers.

In software land, you have "public" and "private" parts of
code, in declarations. The "public" part is what
you give people as your specification. The "private"
part is hidden, or at least is not accessible for any usage.
It's the same with chip specs. The registers are documented,
but they don't tell you how they're making coleslaw inside
the chip, as that is a Trade Secret.

   Paul