Re: [PARPORT] Reverse engineering for Creative Webcam
Wed, 21 Oct 1998 16:16:06 -0400 (EDT)

> Hello to everybody. I would like to know if there is a program
> that just read all the input lines in the parallel port to record, so one
> can figure out what is the handshaking and data transfer between a PC and
> a devuice attach to its parallel por (in this case a Creative Webcam)
> The idea is to have a PC running under Win95 and the Webcam
> connected to it, but also, record all the data transfer between them
> in other PC runnig under linux (the most obviuos i think).

Somebody actually sells some hardware and software to make a simple
18 channel logic analyser out of a PC, but the sample rate is limited
by the ISA bandwidth. I think you'd find it pretty difficult to
get useful information with such a setup. Even in nybble mode, the Webcam
is going to require you to capture at least one bit change for every
ISA I/O cycle. You would have to keep your sampler in perfect sync
with the PC driving the camera - which is well nigh impossible.
(Considering that you need to be able to _do_ something with the data
you collect !).

Clive Turvey has some code to make a Windows VxD to capture i/o
cycles in a manner similar to what I do with DOSemu, but you'll need
a Windows programming guru to make something useful out of it, I think.
(I found it completely unintelligible, but I know nothing about programming
for Windows.)

If you can make the camera work under Wine, there is some code around
to capture i/o traces through that emulator.

The best solution, of course, is to find somebody with a big hardware
multichannel logic analyser ;-)

Grant R. Guenther

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This archive was generated by hypermail 2.0b3 on Wed 30 Dec 1998 - 10:18:39 EST