Re: gEDA-user: Cheaper right angle component video terminal?

[Ben Jackson <ben@xxxxxxx>]

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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