Philibert Perusse wrote:
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> Suppose this problem. You have to take an VGA 640x480 RGB signal where on
> each color is mapped an grayscale image so we have
> three differents images comings at 60Hz...What you have to do with this VGA
> signal is to show it at 180Hz on a particular monochrome LCD display. You
> have to show the three monochrome images that composed the VGA signal one
> after the other. So lets look at
> a solution of this problem.
>
> I think that you must digitalize (GRAB) the 3 colors independently and
> store them before to take them to the LCD one color frame at the time. So,
> this problem is almost the same than to make a frame grabber that grab a VGA
> signal and store it into any kind of memory (I do prefer to use FIFOs).
> Moreover, the complete design must take place over a single 5"x4" board.
> It's my solution but is someone has a better idea!!!!
>
> So, here is MY problem. Is-it realistic to do this in 10 weeks (15 hours a
> week) with a total cost (for each unit, not considering the development) of
> maximum 500$ by unit?
>
> I think not! (Considering that Cypress 128k FIFOs cost 150$ each) But I hope
> I'm not wrong because I'll try to explain that to my boss!!!
>
> (You've probably remark my poor english...is't because I'am a french
> canadian!!!!)
It is possible, but there's zero margin for error. I would recommend
that you investigate Philips TDA8752. This puppy is perfect for your
application. It has three 8-bit A/D converters, phase locked loop, and
color control all integrated into one 100pin QFP. It's programmed via an
I2C interface (for which I of course controlled with a PIC in my
application). For the memory I would recommend good old-fashioned EDO
DRAM. It turns out that you can preselect the DRAM row address during
the Horizontal blank time and write a video row's worth of data without
having to change to another RAM address. You will need two banks of DRAM
with this approach (ping-ponging between writing one while reading the
other). A mid-range FPGA such as a Xilinx 3100 or perhaps one of the
Altera 7000 series parts is more than enough to control all of the
logic.
Get to work, you only have 9 weeks and 5 days left!
Scott
