15 Jun
2006
15 Jun
'06
1:34 a.m.
[Elektor's copy-protected chips]
Of course.
As a womewhat related issue, it annoys me when a service manual isn't
available for some expensice electornic insturment. OK, you can
understand that most users of, say, a TV set, won't understand a
schematic. But I would hope most users of a 'scope would be able to
understand one!
[...]
Ture enough. In fact I've heard it said that hobbies are intended to use
up the money you make doing a 'real' job :-)
[ Homebrew procrssors]
Microcontrollers, PALs/GAls, CPLDs. All come with the security fuse
blown. Obviously EPROMs are readable :-)
Many (small) PALs/GALs can be reverse engineered "empirically". Depends on how much buried state they have. If there
is none
*buried* (i.e. if all of the state is visible on pins) I have
a routine I wrote many years ago that will exhaustively apply
test vectors and track state transitions to rebuild a state table
suitable for applying to a logic compiler (which will then
generate the actual logic equations). IIRC, it is a NS32000
Been there, done that. OK, I did it partly by hand, but I figured out the
logic equations for the PALs on a 286 motherboard that way years ago (and
programmed them into GALs to prove I'd got them right -- the machine
worked perfectly with my GALs fitted).
COFF binary, though... I'd have to hunt to see
which tape has
the sources (something I probably should do, anyway, since
tape isnt very long-lived)
Mostly PICs, AVRs and 8051-derivatives.
In a few cases, they make the object (binary)
file available to program
your own device, but not the source. Which is not particularly helpful.
Are these "old school" MCU's? ARMs? etc. I have quite a number of dissasemblers that would make quick work of this.
If the code
was written in a HLL, then it's usually very easy to deduce the
Of course therre are ways to decipher it, but is it worth doing? Or is it
more pleasant (in the case of a magazine project) just to design your own
version from scratch?
Exactly. Something vendors fail to realize when the
produce a
product that they think is so "special"/unique. But, for other
I can rememebr years ago we got some device at the place where I was
working (I forget what it was, possibly a stepper motor driver). The
schematic was only available under an NDA, which we were thinking of
signing. But before we bothered to do that, I just pulled the device
apart and produced my own schematic (and there wasn't even anything
remotely clever about it!).
I don't
expect them to support all my old machines, but I wish they'd let
_me_ do so by documentign the interface properly. If a device plugs into
a serial port and uses the Tx and Rx line conventionally, then I'd like
to know what commands I can send the device, and how it responds. Or
alternatively, give me the source to the firmware and/or the PC program
and I'll work it out.
Exactly. After all, these publications are intended for people
who *can* do that sort of thing! they're
not cheap). The metal to make said clock is around \pounds 100.
And the result is a much worse timekeeper than a 5 quid quartz clock from
the local household shop.
Of course. Nor does collecting old computers! :> I think once the 2901 "fell from grace" (?),
this became a thing
of the past. I've designed two processors "from scratch" (TTL
Maybe, althoguh i never cared much for the 2901...
with bipolar ROMs for the microcode store) and found
it quite
an interesting exercise. Not just the "logic design" but
actually thinking about what the instruction set should be
for that particular application domain, etc.
But, nowadays, I think it would be a lot less tedious if you
could do it in a big FPGA using synthesis tools. You could
Hmm... I had to use FPGAs in my last job, and I hated every darn minute
of it. Don't get me wrong, I can and will use them if somebody is paying
me to do so, but I won't chose them for my own design. I found it a lot
quicker to debug a circuit by changing things on the actual hardware
(rathen than waiting for your design to complie again, and finding the
darn compiler had removed most of your logic without warning because
you'd tiend an enable pin to the wrong state). And I wouldn't trust that
simulator as far as I could throw it ... No, for my own hobby designs,
I'll stick to boards of TTL and a logic analyser.
So, is it your opinion that the "build it"
mentality is
so individualistic that the differences in attitudes towards
it between our sides of the pond are more *cultural* (of
I am not sure it is different in the UK. Very few people do any kind of
homebrewing over here any more. There are a few of us left, I guess,
that's all.
-tony