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Hardware > How does the TV-Tuner/color monitor work on the GBA?

#1441 - runtime - Sat Jan 18, 2003 9:38 pm

Hey all,
long time fan of GBA, first time poster on GABdev,

Now, Im assuming that the reader of this thread has seen the TV-Tuner / color monitor adapter for the GBA, if not click here.


My question(s) is:
How does it work?

futhermore, can you send analog video stream (TV signal or composite video) to the GBA?

Ultimately, I would like to take a video color spy-camera (composite NTSC video) and display it onto the GBA's Display.

Now I understand there will be electronics and software engineering envolved, and Im not afraid to venture both either. So please throw as many ideas as you can.

Here is a typical flow / block diagram that Im researching on:

{ Analog vid signal } --> { xxx } --> { XPort Dev Cartridge, by charmedlabs } --> { VRAM/WRAM } --> { 'video' player code/program } --> { GBA Display }

Were xxx are methods or techniques to translate or sample to a signal that the GBA can utilize:
1) PWM (pulse width modulation)
2) PPM (oulse position modulation)
3) PCM (pulse coded modulation)
4) a combo of PWM, PPM and PCM
5) No translation needed? (I doubt that, but I could be wrong)

and if any is used,

What code type or program needed? will it promote high CPU usage?


Any ideas, comments, questions, flames, or even support are greatly appreciated!

thanx in 'advance'd
ramie

#1442 - ampz - Sat Jan 18, 2003 10:32 pm

The xxx part must include a high speed video ADC, and a large FIFO if the resolution is low enough. If you're going for a high resolution solution, then it need to include a complete framebuffer. A double framebuffer if you want higher framerates.

This is a major piece of hardware. To start with, I'd suggest using a CCD camera with digital outputs, that way you eliminate the ADC.
I suppose it _might_ be possible to utilise the FPGA in the xport for much of the logic needed for a framebuffer, but you still need the double buffer itself (2*SRAM).
You'll need about 100 FPGA pins, (maybe more), is the xport enough? I doubt it...
The xport might have enough pins for a single buffer (1*SRAM). But that will give you a huge framerate penalty (like half the framerate).

EDIT:
From the sound of it (PWM, PPM, etc. have nothing to do with cameras and digital video), you don't have much knowledge of electronics at all. You'll need a few university courses in digital electronics and computer systems before you can pull this off.