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Old 19 October 2008, 00:47   #1
xazarus
 
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Amiga CD32 Native Resolution?

This may be a noob question, I guess, but I've looked everywhere, and only gotten very unclear answers varying from 1280x512 (which seems unreasonably high for the console generation and I'm pretty sure is too high for the AGA to support) to 312x200.

So I was hoping for a definitive answer, from people who know what they're talking about: What's the Amiga CD32's native resolution?
(just to be clear, by native resolution i mean the best resolution it can be used in that's not simply enlarging the picture)

Last edited by xazarus; 19 October 2008 at 00:53.
 
Old 19 October 2008, 01:52   #2
alexh
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The Amiga range (including CD32) has a programmable video chip capable of a wide range of video resolutions.

The most common resolution of CD32 games would be 320x256 but it can and does change mid-game, even mid screen on some titles.

Keep in mind that 720x576 is the maximum resolution of an interlaced PAL TV (without overscan).

Last edited by alexh; 19 October 2008 at 01:58.
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Old 19 October 2008, 01:53   #3
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Quote:
Originally Posted by xazarus View Post
This may be a noob question, I guess, but I've looked everywhere, and only gotten very unclear answers varying from 1280x512 (which seems unreasonably high for the console generation and I'm pretty sure is too high for the AGA to support) to 312x200.

So I was hoping for a definitive answer, from people who know what they're talking about: What's the Amiga CD32's native resolution?
(just to be clear, by native resolution i mean the best resolution it can be used in that's not simply enlarging the picture)
Pal non-interlaced:
320x256
640x256
1280x256

Pal interlaced:
320x512
640x512
1280x512

Those are the most wide spread resolutions. Each of these supports 1 to 8 bits per pixel.

Note that the 1280 is not a wrong number. Yep, you better believe it In fact, with overscan it goes as high as 1440x566

Last edited by Thorham; 19 October 2008 at 08:15.
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Old 19 October 2008, 02:00   #4
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1280 modes compatible with TV's?
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Old 19 October 2008, 02:03   #5
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Quote:
Originally Posted by alexh View Post
1280 modes compatible with TV's?
True, but xazarus asked about the cd32's resolution, not the resolution of TV's. Subtle difference
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Old 19 October 2008, 04:27   #6
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Does the CD32 have any native resolutions, like a lookup table stored in the rom?

I thought it all just was programmed screen modes and that it did whatever resolution you told it? As long as the hardware could keep up drawing..
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Old 19 October 2008, 08:14   #7
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Originally Posted by spiff View Post
Does the CD32 have any native resolutions, like a lookup table stored in the rom?
I have no idea, however, the rom is just a kickstart rom (3.1?) as far as I know, and as such is has a function to open screens in different resolutions and color mode combinations.

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I thought it all just was programmed screen modes and that it did whatever resolution you told it? As long as the hardware could keep up drawing..
Yes. All the screenmodes are programmed.
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Old 19 October 2008, 11:54   #8
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Note that "programmable" means programmable display start and end position, PC-style fully programmable pixel clock is not possible. (only choices are 140ns,70ns or 35ns pixel clocks = lores/hires/superhires)
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Old 19 October 2008, 14:21   #9
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If by 'native' you mean 'most common' then the answer is 640x256 (or 640x200, seeing as you're in US and have NTSC TVs)
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Old 19 October 2008, 16:19   #10
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Originally Posted by alphonsus View Post
If by 'native' you mean 'most common' then the answer is 640x256 (or 640x200, seeing as you're in US and have NTSC TVs)
Surely that is not true. Most common is surely lores i.e. 320x256 (320x240) as I said above
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Old 20 October 2008, 10:59   #11
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Quote:
Originally Posted by Toni Wilen View Post
Note that "programmable" means programmable display start and end position, PC-style fully programmable pixel clock is not possible. (only choices are 140ns,70ns or 35ns pixel clocks = lores/hires/superhires)
The only limitation is the dma-collaps
.. black screen .. frozzen system ..

1024x768
1280x720

1280x1024 ?!
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Old 20 October 2008, 12:07   #12
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Originally Posted by Ratte View Post
The only limitation is the dma-collaps
.. black screen .. frozzen system ..
Try to program something like 256 pixel wide screen mode that is TV-compatible. I don't think you can do that without programmable pixel clock

EDIT: 256 pixel wide = 256 pixel wide mode that fills same area as regular 320 pixel lores mode.

Last edited by Toni Wilen; 20 October 2008 at 12:37.
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Old 20 October 2008, 13:44   #13
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Quote:
Originally Posted by Toni Wilen View Post
Try to program something like 256 pixel wide screen mode that is TV-compatible. I don't think you can do that without programmable pixel clock

EDIT: 256 pixel wide = 256 pixel wide mode that fills same area as regular 320 pixel lores mode.
Thats true ...
(HighGFX LowRes DblScan => 256 x 192 , but not TV compatible)


EDIT:
With collaps I mean, broken ChipMem refresh.
This could happen if you programm very long scanlines (wide screens).
The Hardware need some minimum "blanks" for DMA-refresh (paula = audio and disk dma).

Last edited by Ratte; 20 October 2008 at 13:49.
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Old 21 October 2008, 00:54   #14
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1472 x 566 in PAL Super Hi-Res Laced Maximum Overscan would be the highest resolution without additional hardware (SX32 VGA adapter).
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