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Re: gEDA-user: Cheaper right angle component video terminal?
On Mon, Nov 16, 2009 at 02:21:16PM -0800, Anthony Shanks wrote:
> Wow, that is a very similar project I am working on myself (although
> our goals are different),
That reminds me that every time I see a "cheat at guitar hero" hack I
consider that my board would be ideal for making such a thing.
> did you do all the work yourself and how long did it take?
I did do everything myself. I had to reverse engineer the original board,
identify and source all of the board-to-panel connectors, choose the parts,
design the board (which involved moving to geda/PCB and making many
improvements to PCB itself!), code the FPGA and the microcontroller. I
even made a remote control for it eventually.
If you don't count the part where I worked on the original embedded PC
(fixing bugs in their board, adding audio support, reverse-engineering
a few kernel drivers so I could port to newer Linux, performance
enhancements to the ATI Mach64 driver...) the part where I worked toward
the hardware solution took about a year and a half.
> What ADC/DAC are you using and what processor are
> you using for the data processing?
The ADC is an Analog ADV7183B. It's a really awesome part. The output
of that goes to a Cyclone II FPGA which does the data processing. It
has two SSRAMs for framebuffering (DRAM would be cheaper but I had the
SSRAMs for free) Both are on an I2C bus and get parameter configuration
from an atmega8.
> What opamps are you using to drive
> the video? Max resolution? Did you consider a HDMI interface instead
> of component?
The output is 24 bit parallel RGB driven directly by the FPGA, so there
are no video output stages. That was the purpose of the board -- without
it you can't display anything at all on the plasma panel. It has no
other inputs. When it was driven by the embedded PC it was connected
to a FPD-link demux (takes a 4-wire high-speed-serial link directly from
the graphics chipset, typically used to cross the hinge of a laptop).
The display's resolution is 852x480 ("EDTV"). That's the size (with
square pixels) that you scale anamorphic squeezed input to for 16:9.
A lonng way into the project I realized I could probably make a very
simple board that would include a DVI demux and a EEPROM and make it look
like a DVI monitor, but that wasn't really my goal and I didn't pursue
it. I might have put HD input on it, but the Analog chips slightly upscale
from the one I picked (which include HD and VGA inputs) don't have docs
online.
--
Ben Jackson AD7GD
<ben@xxxxxxx>
http://www.ben.com/
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