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PostPosted: Wed Feb 06, 2019 10:49 am 
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Hello there. There's documents written about voltages for systems like nes (kevtris), megadrive (TmEE), master system (TmEE), SC-3000 (TmEE). I haven't been able to find measurements for other systems like snes (byuu says non-linear ramp with notably darker greys), psx (no$cash mentions a non-linear ramp, largely brighter than normal greys), pc engine, n64. Mostly interested for "purist" sake. Thanks.


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PostPosted: Wed Feb 06, 2019 7:44 pm 
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Location: NE Indiana, USA (NTSC)
I'd like to see voltages for Super NES and GameCube in order to display IRE levels in Super Game Boy and Game Boy Player software.

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PostPosted: Wed Feb 06, 2019 11:31 pm 
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Location: Estonia, Rapla city (50 and 60Hz compatible :P)
If someone can make a test ROM that shows a greyscale ramp I'll be able to take measurements on SNES and PCE/TG16 aswell. The ramp needs to show a solid white bar on left edge, then go to black and progressively higher until it reaches white and then to black again. White on left allows to me to know exactly where the useful image begins.
End result is a bunch of vertical bars of all available shades.

PCE is going to be fun because it has two types of outputs, RGB and Y with modulated chroma components and latter uses a LUT to create a different result. I'm not sure how one will go about measuring the chroma components, one will have to know the phase difference compared to color subcarrier to get anywhere. My equipment is not able to report such info and doing it manually is very error prone.

Hardware with a very fine ramp would need it to be split up into multiple ramps, separated by a button press or such. One quarter on one screen, other quarter on the next etc. Otherwise it will be too difficult to tell individual levels apart.

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PostPosted: Thu Feb 07, 2019 12:54 am 
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Here's something I quickly whipped together for measuring the SNES DACs. Displays grey ramp on every scanline, starting with white on both leftmost and rightmost pixels, black bars to separate things, and then 224 pixels going from <0,0,0> black to <31,31,31> white. Additionally uses HDMA to adjust the reportedly-analog dimming factor, 7 scanlines for each value.


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File comment: screen shot from bsnesplus
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PostPosted: Thu Feb 07, 2019 1:01 am 
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Location: Estonia, Rapla city (50 and 60Hz compatible :P)
That analog dimming should be under a button press or such if I were to measure it. My scope lacks video line triggers (DRM option no less lol) and it has not enough memory to do a full frame capture. I can only work with a stable frame with solid vertical bars per one test, once all bars are measured I can go onto the next.

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PostPosted: Thu Feb 07, 2019 11:21 am 
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.... lulz.

Up (brighter) and down (dimmer) change analog dimming level, wrapping around.


(edit: this was apparently my 8086th post)


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Last edited by lidnariq on Sun Feb 10, 2019 11:46 am, edited 1 time in total.
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PostPosted: Thu Feb 07, 2019 6:52 pm 
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Joined: Sun Mar 19, 2006 9:44 pm
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Location: Japan
Here's a similar simple PCE ROM that I whipped up.

You can cycle through some basic RGB etc palettes by pressing any button or pad direction (except for RUN or I to account for flashcart menu buttons).


[edit] ROM updated to guarantee SPR palette & screen border are black.


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