Video modes on Gamecube
Rob Reilink <[email protected]> Fri, 03 Mar 2006 21:56:48 +0100
| Newsgroups | gmane.linux.ports.game-cube.devel |
|---|---|
| Message-ID | <[email protected]> |
Hi all,
I'm trying to see if it is possible to hoop up a TFT LCD (from an old
laptop) to the gamecube digital video output. The output seems to be
reasonably compatible with the timing required for the TFT.
What I have found in patent 6609977
(http://freepatentsonline.com/6609977.html, search for Example Video
Interface)
The digital output outputs Y, Cr, Y ,Cb data on a fixed rate of 27 MHz
and the output format is selectable between NTSC, PAL, MPAL(?) and Debug
(CCIR656). The 27MHz makes sense for about 640 pixels horizontally for
interlaced video. TFT displays however require non-interlaced data. To
avoid using a difficult conversion, it is nescessary to use a 54MHz
pixel clock, which should be possible according to the patent:
VI Clock Select Register (R/W)
This register selects whether the VI will receive a 27 Mhz or a 54 Mhz
clock. The 54 Mhz clock is used only with the progressive
display modes.
VICLKSEL 1 0 -27 Mhz video clk 0
1 -54 Mhz video clk
Is it possible with the current gcnfb module to select other modes than
PAL or NTSC? Or is there an other way to
tweak around with the video registers?
This interlaced/non-interlaced issue seems to be the only problem in
interfacing TFT LCD's to the GC, since the timing is quite compatible on
all other cases and interfacing should be a matter of a simple CPLD to
split the data stream, extract sync data and convert it to RGB.
Kind regards,
Rob
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