20 Jan
2008
20 Jan
'08
4:08 p.m.
16L8ACN. This is the PAL aboard the Acculogic
sIDE-1/16 XT-IDE controller I mentioned. Someone asked :)
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22 Jan
22 Jan
4:14 a.m.
On Sunday 20 January 2008 21:08:51 Chris M wrote:
16L8ACN. This is the PAL aboard the Acculogic
sIDE-1/16 XT-IDE controller I mentioned. Someone asked :)
... and here's a datasheet.
http://noel.feld.cvut.cz/hw/philips/acrobat/6052.pdf
Now, correct me if I'm wrong, but that seems to suggest that some of the pins
are always inputs, and some may be configured as inputs or outputs.
I reckon it would be possible to work out what's configured as input and
what's configured as output, and from that determine the truth table of the
PAL by brute-force methods (just try all the inputs in turn). From there you
can start looking at how to reproduce it.
Or, it might be doing something so blindingly obvious that you don't even need
to do that - it could be that you could figure it out just from what it
decodes and what it drives...
Probably someone will point out a fatal flaw in this.
Gordon.
12:02 p.m.
I'd go as far as to melt the epoxy off the thing to
get at the internal configuration. But only if burning
a new PAL is easy and cheap.
--- Gordon JC Pearce <gordonjcp at gjcp.net> wrote:
On Sunday 20 January 2008 21:08:51 Chris M wrote:
____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs
16L8ACN. This is the PAL aboard the Acculogic
sIDE-1/16 XT-IDE controller I mentioned. Someone
asked :)
... and here's a datasheet.
http://noel.feld.cvut.cz/hw/philips/acrobat/6052.pdf
Now, correct me if I'm wrong, but that seems to
suggest that some of the pins
are always inputs, and some may be configured as
inputs or outputs.
I reckon it would be possible to work out what's
configured as input and
what's configured as output, and from that determine
the truth table of the
PAL by brute-force methods (just try all the inputs
in turn). From there you
can start looking at how to reproduce it.
Or, it might be doing something so blindingly
obvious that you don't even need
to do that - it could be that you could figure it
out just from what it
decodes and what it drives...
Probably someone will point out a fatal flaw in
this.
Gordon.
23 Jan
23 Jan
8:32 a.m.
From: chrism3667 at yahoo.com
I'd go as far as to melt the epoxy off the thing
to
get at the internal configuration. But only if burning
a new PAL is easy and cheap.
--- Gordon JC Pearce wrote:
Hi
It is a L device. All can easily be deduced from the pins.
As for cases that the line may be either input or output.
putting the an input signal through a resistor would
be enough. Use a 1 K. If you can pull it low and high
with a 1 K series, it is not driven internally.
Dwight
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On Sunday 20 January 2008 21:08:51 Chris M
wrote:
16L8ACN. This is the PAL aboard the Acculogic
sIDE-1/16 XT-IDE controller I mentioned. Someone
asked :)
22 Jan
22 Jan
2:58 p.m.
On Sunday 20 January 2008 21:08:51 Chris M wrote:
Correct. The 16L8 (IIRC) has 10 pins that are always inputs, 2 pins that
are always outputs amd 6 pins that can be configured as either. And note
that you can take feedback from those 6 (if configured as outputs) into
the logic array, thus meaning you can make sequentioal circuits
(flip-flops, etc).
That last can really complicate things. It means, for example, the
concept of a truth table may not be valid (it's a 'sequence table', and
that just cylcing through all the inputs and seeing what the outputs do
is not enough. However, note there is no 'hidden state'. If the chip is
programemd to make flip-flops, etc, then the output of each flip-flop
appears on a pin (this is not true of more complex programmable logic
chips). So there is some hope in cracking it.
16L8ACN. This is the PAL aboard the Acculogic
sIDE-1/16 XT-IDE controller I mentioned. Someone asked :)
... and here's a datasheet.
http://noel.feld.cvut.cz/hw/philips/acrobat/6052.pdf
Now, correct me if I'm wrong, but that seems to suggest that some of the pins
are always inputs, and some may be configured as inputs or outputs.
I reckon it would be possible to work out what's configured as input and
what's configured as output, and from that determine the truth table of the
PAL by brute-force methods (just try all the inputs in turn). From there you
can start looking at how to reproduce it.
I would start by tracing scheamtics of the board if you;ve not already
done so. That should tell you which pins are inputs and which are outputs
(and which, if any, are bidirectional). It may also indicate if the
device is possibly sequetional (if, for example, it's just an address
decoder, then it's very likely to be purely combinatorial).
-tony
5:54 p.m.
I do have jpegs of this board if anyone is interested.
--- Tony Duell <ard at p850ug1.demon.co.uk> wrote:
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On Sunday 20 January 2008 21:08:51 Chris M wrote:
> 16L8ACN. This is the PAL aboard the Acculogic
> sIDE-1/16 XT-IDE controller I mentioned. Someone
asked :)
... and here's a datasheet.
http://noel.feld.cvut.cz/hw/philips/acrobat/6052.pdf
Now, correct me if I'm wrong, but that seems to
suggest that some of the pins
are always inputs, and some may be configured as
inputs or outputs.
Correct. The 16L8 (IIRC) has 10 pins that are always
inputs, 2 pins that
are always outputs amd 6 pins that can be configured
as either. And note
that you can take feedback from those 6 (if
configured as outputs) into
the logic array, thus meaning you can make
sequentioal circuits
(flip-flops, etc).
That last can really complicate things. It means,
for example, the
concept of a truth table may not be valid (it's a
'sequence table', and
that just cylcing through all the inputs and seeing
what the outputs do
is not enough. However, note there is no 'hidden
state'. If the chip is
programemd to make flip-flops, etc, then the output
of each flip-flop
appears on a pin (this is not true of more complex
programmable logic
chips). So there is some hope in cracking it.
I reckon it would be possible to work out what's
configured as input and
what's configured as output, and from that
determine the truth table of the
PAL by brute-force methods (just try all the
inputs in turn). From there you
can start looking at how to reproduce it.
I would start by tracing scheamtics of the board if
you;ve not already
done so. That should tell you which pins are inputs
and which are outputs
(and which, if any, are bidirectional). It may also
indicate if the
device is possibly sequetional (if, for example,
it's just an address
decoder, then it's very likely to be purely
combinatorial).
-tony
6020
days inactive
6023
days old
5 comments
4 participants
participants (4)
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ard＠p850ug1.demon.co.uk -
chrism3667＠yahoo.com -
dkelvey＠hotmail.com -
gordonjcp＠gjcp.net