Arfa Daily wrote:


"Franc Zabkar" wrote in message
...
On Sun, 16 Sep 2007 01:52:07 GMT, "Arfa Daily"
put finger to keyboard and composed:

Anybody got any data on a VGT7616-2077 ? Particularly interested in
pinouts.
It's used in a Burle video surveillance camera, so if anyone has any
schematics for any Burle cameras, it may appear on one of them. Can't
give the model unfortunately as, even though there is a model / serial
number plate on it, nothing has ever been printed or stamped on it ...

I have tried all the usual data sheet sources without success. There's a
couple of pages of good hits for it on Google, so it's a readily
recognised
device, but half the sites are Chinese, and unreadable even after
translation, and the rest refer off to other sites for the data sheet,
which
then don't actually have it. Not desperate, as it's for a 'project'
rather than a repair, but it sure would make working up the mods that I
need to do
to the camera, a lot easier with some pinning data for this chip.

Thanks all

Arfa

All I can find are references to VGT7616-nnnn in a 44PLCC package with
date codes around 1988. Usbid.com says it is a Vitelic part, but other
sites suggest it was made by VLSI Technology. My cross reference book
lists VGC prefixes (but no VGT parts) for VLSI Tech, so I would lean
toward the latter. I suspect the part is a field or mask programmable
ASIC of some kind, as that was VLSI Tech's forte. The variable suffix
would tend to support this.

- Franc Zabkar

Hi Franc

That was my first thought as well, as soon as I saw the dash number on it,
but I was encouraged when I found plenty of references to it on the net,
as well as others from the same series but with different dash numbers. I
figured that maybe rather than it being an OEM-specific programmed device,
that perhaps it was just programmed up to be a 'useful' chip. It seems to
do most of the timing for the CCD readout process, as well as V & H sync
generation.

I reckon 1988 would be about right. What I am trying to do with this
camera, is to replace a vidicon camera in a system, whose timebases are
derived directly from pulses supplied by an external part of the system.
If I can figure which pins are ins and which are outs, I may be able to
synchronise the VGT chip to the external system. There are plenty of pins
which have H rate and V rate pulses on them, so I think that it's
potentially promising. Thanks for your interest anyway.

Arfa

If you can find the reference frequency source for the chip (probably a
crystal oscillator I would expect) then you could add some varactors (or
swap it for a VCXO module) and make it tunable and then use a PLL chip like
a 9046 to compare the VSync pulses from the camera with your external Vsync
signal, that should get allow you to get the vertical sync to match.
Unfortunately I think that will not necessarily get the HSync to match
because I seem to remember that there is some difference between the even
and odd fields, and I guess that the camera could be doing even fields when
the external sync is doing odd fields. I suspect that it might be better
to get a camera module with the requisite inputs already fitted, especially
if you are not doing this for fun but expect your hours to be paid for in a
monetary sense. If you feel like posting a photo, I'd be interested in
looking at it, but only if is is no trouble because I'll be no help to you.

Chris